spi: spi-pic32: Add PIC32 SPI master driver
The PIC32 SPI driver is capable of performing SPI transfers using PIO or external DMA engine. GPIO controlled /CS support is made default in the driver for correct operation of the controller. This can be enabled by adding "cs-gpios" property of the SPI node in board dts file. Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com> Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Purna Chandra Mandal
Mark Brown
parent
120e8989eb
commit
1bcb9f8ceb
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@ -436,6 +436,12 @@ config SPI_ORION
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help
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help
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This enables using the SPI master controller on the Orion chips.
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This enables using the SPI master controller on the Orion chips.
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config SPI_PIC32
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tristate "Microchip PIC32 series SPI"
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depends on MACH_PIC32 || COMPILE_TEST
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help
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SPI driver for Microchip PIC32 SPI master controller.
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config SPI_PL022
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config SPI_PL022
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tristate "ARM AMBA PL022 SSP controller"
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tristate "ARM AMBA PL022 SSP controller"
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depends on ARM_AMBA
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depends on ARM_AMBA
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@ -62,6 +62,7 @@ obj-$(CONFIG_SPI_OMAP_100K) += spi-omap-100k.o
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obj-$(CONFIG_SPI_OMAP24XX) += spi-omap2-mcspi.o
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obj-$(CONFIG_SPI_OMAP24XX) += spi-omap2-mcspi.o
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obj-$(CONFIG_SPI_TI_QSPI) += spi-ti-qspi.o
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obj-$(CONFIG_SPI_TI_QSPI) += spi-ti-qspi.o
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obj-$(CONFIG_SPI_ORION) += spi-orion.o
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obj-$(CONFIG_SPI_ORION) += spi-orion.o
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obj-$(CONFIG_SPI_PIC32) += spi-pic32.o
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obj-$(CONFIG_SPI_PL022) += spi-pl022.o
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obj-$(CONFIG_SPI_PL022) += spi-pl022.o
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obj-$(CONFIG_SPI_PPC4xx) += spi-ppc4xx.o
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obj-$(CONFIG_SPI_PPC4xx) += spi-ppc4xx.o
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spi-pxa2xx-platform-objs := spi-pxa2xx.o spi-pxa2xx-dma.o
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spi-pxa2xx-platform-objs := spi-pxa2xx.o spi-pxa2xx-dma.o
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@ -0,0 +1,888 @@
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/*
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* Microchip PIC32 SPI controller driver.
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*
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* Purna Chandra Mandal <purna.mandal@microchip.com>
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* Copyright (c) 2016, Microchip Technology Inc.
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*
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* This program is free software; you can distribute it and/or modify it
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* under the terms of the GNU General Public License (Version 2) as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include <linux/clk.h>
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#include <linux/clkdev.h>
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#include <linux/delay.h>
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#include <linux/dmaengine.h>
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#include <linux/dma-mapping.h>
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#include <linux/highmem.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/interrupt.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/of_gpio.h>
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#include <linux/of_address.h>
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#include <linux/platform_device.h>
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#include <linux/spi/spi.h>
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/* SPI controller registers */
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struct pic32_spi_regs {
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u32 ctrl;
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u32 ctrl_clr;
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u32 ctrl_set;
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u32 ctrl_inv;
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u32 status;
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u32 status_clr;
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u32 status_set;
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u32 status_inv;
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u32 buf;
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u32 dontuse[3];
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u32 baud;
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u32 dontuse2[3];
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u32 ctrl2;
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u32 ctrl2_clr;
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u32 ctrl2_set;
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u32 ctrl2_inv;
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};
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/* Bit fields of SPI Control Register */
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#define CTRL_RX_INT_SHIFT 0 /* Rx interrupt generation */
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#define RX_FIFO_EMTPY 0
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#define RX_FIFO_NOT_EMPTY 1 /* not empty */
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#define RX_FIFO_HALF_FULL 2 /* full by half or more */
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#define RX_FIFO_FULL 3 /* completely full */
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#define CTRL_TX_INT_SHIFT 2 /* TX interrupt generation */
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#define TX_FIFO_ALL_EMPTY 0 /* completely empty */
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#define TX_FIFO_EMTPY 1 /* empty */
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#define TX_FIFO_HALF_EMPTY 2 /* empty by half or more */
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#define TX_FIFO_NOT_FULL 3 /* atleast one empty */
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#define CTRL_MSTEN BIT(5) /* enable master mode */
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#define CTRL_CKP BIT(6) /* active low */
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#define CTRL_CKE BIT(8) /* Tx on falling edge */
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#define CTRL_SMP BIT(9) /* Rx at middle or end of tx */
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#define CTRL_BPW_MASK 0x03 /* bits per word/sample */
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#define CTRL_BPW_SHIFT 10
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#define PIC32_BPW_8 0
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#define PIC32_BPW_16 1
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#define PIC32_BPW_32 2
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#define CTRL_SIDL BIT(13) /* sleep when idle */
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#define CTRL_ON BIT(15) /* enable macro */
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#define CTRL_ENHBUF BIT(16) /* enable enhanced buffering */
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#define CTRL_MCLKSEL BIT(23) /* select clock source */
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#define CTRL_MSSEN BIT(28) /* macro driven /SS */
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#define CTRL_FRMEN BIT(31) /* enable framing mode */
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/* Bit fields of SPI Status Register */
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#define STAT_RF_EMPTY BIT(5) /* RX Fifo empty */
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#define STAT_RX_OV BIT(6) /* err, s/w needs to clear */
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#define STAT_TX_UR BIT(8) /* UR in Framed SPI modes */
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#define STAT_FRM_ERR BIT(12) /* Multiple Frame Sync pulse */
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#define STAT_TF_LVL_MASK 0x1F
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#define STAT_TF_LVL_SHIFT 16
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#define STAT_RF_LVL_MASK 0x1F
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#define STAT_RF_LVL_SHIFT 24
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/* Bit fields of SPI Baud Register */
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#define BAUD_MASK 0x1ff
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/* Bit fields of SPI Control2 Register */
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#define CTRL2_TX_UR_EN BIT(10) /* Enable int on Tx under-run */
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#define CTRL2_RX_OV_EN BIT(11) /* Enable int on Rx over-run */
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#define CTRL2_FRM_ERR_EN BIT(12) /* Enable frame err int */
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/* Minimum DMA transfer size */
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#define PIC32_DMA_LEN_MIN 64
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struct pic32_spi {
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dma_addr_t dma_base;
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struct pic32_spi_regs __iomem *regs;
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int fault_irq;
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int rx_irq;
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int tx_irq;
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u32 fifo_n_byte; /* FIFO depth in bytes */
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struct clk *clk;
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struct spi_master *master;
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/* Current controller setting */
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u32 speed_hz; /* spi-clk rate */
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u32 mode;
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u32 bits_per_word;
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u32 fifo_n_elm; /* FIFO depth in words */
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#define PIC32F_DMA_PREP 0 /* DMA chnls configured */
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unsigned long flags;
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/* Current transfer state */
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struct completion xfer_done;
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/* PIO transfer specific */
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const void *tx;
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const void *tx_end;
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const void *rx;
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const void *rx_end;
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int len;
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void (*rx_fifo)(struct pic32_spi *);
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void (*tx_fifo)(struct pic32_spi *);
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};
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static inline void pic32_spi_enable(struct pic32_spi *pic32s)
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{
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writel(CTRL_ON | CTRL_SIDL, &pic32s->regs->ctrl_set);
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}
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static inline void pic32_spi_disable(struct pic32_spi *pic32s)
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{
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writel(CTRL_ON | CTRL_SIDL, &pic32s->regs->ctrl_clr);
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/* avoid SPI registers read/write at immediate next CPU clock */
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ndelay(20);
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}
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static void pic32_spi_set_clk_rate(struct pic32_spi *pic32s, u32 spi_ck)
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{
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u32 div;
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/* div = (clk_in / 2 * spi_ck) - 1 */
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div = DIV_ROUND_CLOSEST(clk_get_rate(pic32s->clk), 2 * spi_ck) - 1;
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writel(div & BAUD_MASK, &pic32s->regs->baud);
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}
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static inline u32 pic32_rx_fifo_level(struct pic32_spi *pic32s)
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{
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u32 sr = readl(&pic32s->regs->status);
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return (sr >> STAT_RF_LVL_SHIFT) & STAT_RF_LVL_MASK;
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}
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static inline u32 pic32_tx_fifo_level(struct pic32_spi *pic32s)
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{
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u32 sr = readl(&pic32s->regs->status);
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return (sr >> STAT_TF_LVL_SHIFT) & STAT_TF_LVL_MASK;
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}
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/* Return the max entries we can fill into tx fifo */
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static u32 pic32_tx_max(struct pic32_spi *pic32s, int n_bytes)
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{
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u32 tx_left, tx_room, rxtx_gap;
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tx_left = (pic32s->tx_end - pic32s->tx) / n_bytes;
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tx_room = pic32s->fifo_n_elm - pic32_tx_fifo_level(pic32s);
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/*
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* Another concern is about the tx/rx mismatch, we
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* though to use (pic32s->fifo_n_byte - rxfl - txfl) as
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* one maximum value for tx, but it doesn't cover the
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* data which is out of tx/rx fifo and inside the
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* shift registers. So a ctrl from sw point of
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* view is taken.
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*/
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rxtx_gap = ((pic32s->rx_end - pic32s->rx) -
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(pic32s->tx_end - pic32s->tx)) / n_bytes;
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return min3(tx_left, tx_room, (u32)(pic32s->fifo_n_elm - rxtx_gap));
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}
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/* Return the max entries we should read out of rx fifo */
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static u32 pic32_rx_max(struct pic32_spi *pic32s, int n_bytes)
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{
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u32 rx_left = (pic32s->rx_end - pic32s->rx) / n_bytes;
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return min_t(u32, rx_left, pic32_rx_fifo_level(pic32s));
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}
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#define BUILD_SPI_FIFO_RW(__name, __type, __bwl) \
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static void pic32_spi_rx_##__name(struct pic32_spi *pic32s) \
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{ \
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__type v; \
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u32 mx = pic32_rx_max(pic32s, sizeof(__type)); \
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for (; mx; mx--) { \
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v = read##__bwl(&pic32s->regs->buf); \
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if (pic32s->rx_end - pic32s->len) \
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*(__type *)(pic32s->rx) = v; \
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pic32s->rx += sizeof(__type); \
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} \
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} \
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\
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static void pic32_spi_tx_##__name(struct pic32_spi *pic32s) \
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{ \
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__type v; \
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u32 mx = pic32_tx_max(pic32s, sizeof(__type)); \
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for (; mx ; mx--) { \
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v = (__type)~0U; \
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if (pic32s->tx_end - pic32s->len) \
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v = *(__type *)(pic32s->tx); \
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write##__bwl(v, &pic32s->regs->buf); \
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pic32s->tx += sizeof(__type); \
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} \
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}
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BUILD_SPI_FIFO_RW(byte, u8, b);
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BUILD_SPI_FIFO_RW(word, u16, w);
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BUILD_SPI_FIFO_RW(dword, u32, l);
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static void pic32_err_stop(struct pic32_spi *pic32s, const char *msg)
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{
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/* disable all interrupts */
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disable_irq_nosync(pic32s->fault_irq);
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disable_irq_nosync(pic32s->rx_irq);
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disable_irq_nosync(pic32s->tx_irq);
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/* Show err message and abort xfer with err */
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dev_err(&pic32s->master->dev, "%s\n", msg);
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if (pic32s->master->cur_msg)
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pic32s->master->cur_msg->status = -EIO;
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complete(&pic32s->xfer_done);
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}
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static irqreturn_t pic32_spi_fault_irq(int irq, void *dev_id)
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{
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struct pic32_spi *pic32s = dev_id;
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u32 status;
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status = readl(&pic32s->regs->status);
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/* Error handling */
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if (status & (STAT_RX_OV | STAT_TX_UR)) {
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writel(STAT_RX_OV, &pic32s->regs->status_clr);
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writel(STAT_TX_UR, &pic32s->regs->status_clr);
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pic32_err_stop(pic32s, "err_irq: fifo ov/ur-run\n");
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return IRQ_HANDLED;
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}
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if (status & STAT_FRM_ERR) {
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pic32_err_stop(pic32s, "err_irq: frame error");
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return IRQ_HANDLED;
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}
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if (!pic32s->master->cur_msg) {
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pic32_err_stop(pic32s, "err_irq: no mesg");
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return IRQ_NONE;
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}
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return IRQ_NONE;
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}
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static irqreturn_t pic32_spi_rx_irq(int irq, void *dev_id)
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{
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struct pic32_spi *pic32s = dev_id;
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pic32s->rx_fifo(pic32s);
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/* rx complete ? */
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if (pic32s->rx_end == pic32s->rx) {
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/* disable all interrupts */
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disable_irq_nosync(pic32s->fault_irq);
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disable_irq_nosync(pic32s->rx_irq);
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/* complete current xfer */
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complete(&pic32s->xfer_done);
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}
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return IRQ_HANDLED;
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}
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static irqreturn_t pic32_spi_tx_irq(int irq, void *dev_id)
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{
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struct pic32_spi *pic32s = dev_id;
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pic32s->tx_fifo(pic32s);
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/* tx complete? disable tx interrupt */
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if (pic32s->tx_end == pic32s->tx)
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disable_irq_nosync(pic32s->tx_irq);
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return IRQ_HANDLED;
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}
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static void pic32_spi_dma_rx_notify(void *data)
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{
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struct pic32_spi *pic32s = data;
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complete(&pic32s->xfer_done);
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}
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static int pic32_spi_dma_transfer(struct pic32_spi *pic32s,
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struct spi_transfer *xfer)
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{
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struct spi_master *master = pic32s->master;
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struct dma_async_tx_descriptor *desc_rx;
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struct dma_async_tx_descriptor *desc_tx;
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dma_cookie_t cookie;
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int ret;
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if (!master->dma_rx || !master->dma_tx)
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return -ENODEV;
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desc_rx = dmaengine_prep_slave_sg(master->dma_rx,
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xfer->rx_sg.sgl,
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xfer->rx_sg.nents,
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|
DMA_FROM_DEVICE,
|
||||||
|
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
|
||||||
|
if (!desc_rx) {
|
||||||
|
ret = -EINVAL;
|
||||||
|
goto err_dma;
|
||||||
|
}
|
||||||
|
|
||||||
|
desc_tx = dmaengine_prep_slave_sg(master->dma_tx,
|
||||||
|
xfer->tx_sg.sgl,
|
||||||
|
xfer->tx_sg.nents,
|
||||||
|
DMA_TO_DEVICE,
|
||||||
|
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
|
||||||
|
if (!desc_tx) {
|
||||||
|
ret = -EINVAL;
|
||||||
|
goto err_dma;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Put callback on the RX transfer, that should finish last */
|
||||||
|
desc_rx->callback = pic32_spi_dma_rx_notify;
|
||||||
|
desc_rx->callback_param = pic32s;
|
||||||
|
|
||||||
|
cookie = dmaengine_submit(desc_rx);
|
||||||
|
ret = dma_submit_error(cookie);
|
||||||
|
if (ret)
|
||||||
|
goto err_dma;
|
||||||
|
|
||||||
|
cookie = dmaengine_submit(desc_tx);
|
||||||
|
ret = dma_submit_error(cookie);
|
||||||
|
if (ret)
|
||||||
|
goto err_dma_tx;
|
||||||
|
|
||||||
|
dma_async_issue_pending(master->dma_rx);
|
||||||
|
dma_async_issue_pending(master->dma_tx);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
|
||||||
|
err_dma_tx:
|
||||||
|
dmaengine_terminate_all(master->dma_rx);
|
||||||
|
err_dma:
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_dma_config(struct pic32_spi *pic32s, u32 dma_width)
|
||||||
|
{
|
||||||
|
int buf_offset = offsetof(struct pic32_spi_regs, buf);
|
||||||
|
struct spi_master *master = pic32s->master;
|
||||||
|
struct dma_slave_config cfg;
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
cfg.device_fc = true;
|
||||||
|
cfg.src_addr = pic32s->dma_base + buf_offset;
|
||||||
|
cfg.dst_addr = pic32s->dma_base + buf_offset;
|
||||||
|
cfg.src_maxburst = pic32s->fifo_n_elm / 2; /* fill one-half */
|
||||||
|
cfg.dst_maxburst = pic32s->fifo_n_elm / 2; /* drain one-half */
|
||||||
|
cfg.src_addr_width = dma_width;
|
||||||
|
cfg.dst_addr_width = dma_width;
|
||||||
|
/* tx channel */
|
||||||
|
cfg.slave_id = pic32s->tx_irq;
|
||||||
|
cfg.direction = DMA_MEM_TO_DEV;
|
||||||
|
ret = dmaengine_slave_config(master->dma_tx, &cfg);
|
||||||
|
if (ret) {
|
||||||
|
dev_err(&master->dev, "tx channel setup failed\n");
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
/* rx channel */
|
||||||
|
cfg.slave_id = pic32s->rx_irq;
|
||||||
|
cfg.direction = DMA_DEV_TO_MEM;
|
||||||
|
ret = dmaengine_slave_config(master->dma_rx, &cfg);
|
||||||
|
if (ret)
|
||||||
|
dev_err(&master->dev, "rx channel setup failed\n");
|
||||||
|
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_set_word_size(struct pic32_spi *pic32s, u8 bits_per_word)
|
||||||
|
{
|
||||||
|
enum dma_slave_buswidth dmawidth;
|
||||||
|
u32 buswidth, v;
|
||||||
|
|
||||||
|
switch (bits_per_word) {
|
||||||
|
case 8:
|
||||||
|
pic32s->rx_fifo = pic32_spi_rx_byte;
|
||||||
|
pic32s->tx_fifo = pic32_spi_tx_byte;
|
||||||
|
buswidth = PIC32_BPW_8;
|
||||||
|
dmawidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
|
||||||
|
break;
|
||||||
|
case 16:
|
||||||
|
pic32s->rx_fifo = pic32_spi_rx_word;
|
||||||
|
pic32s->tx_fifo = pic32_spi_tx_word;
|
||||||
|
buswidth = PIC32_BPW_16;
|
||||||
|
dmawidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
|
||||||
|
break;
|
||||||
|
case 32:
|
||||||
|
pic32s->rx_fifo = pic32_spi_rx_dword;
|
||||||
|
pic32s->tx_fifo = pic32_spi_tx_dword;
|
||||||
|
buswidth = PIC32_BPW_32;
|
||||||
|
dmawidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
|
||||||
|
break;
|
||||||
|
default:
|
||||||
|
/* not supported */
|
||||||
|
return -EINVAL;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* calculate maximum number of words fifos can hold */
|
||||||
|
pic32s->fifo_n_elm = DIV_ROUND_UP(pic32s->fifo_n_byte,
|
||||||
|
bits_per_word / 8);
|
||||||
|
/* set word size */
|
||||||
|
v = readl(&pic32s->regs->ctrl);
|
||||||
|
v &= ~(CTRL_BPW_MASK << CTRL_BPW_SHIFT);
|
||||||
|
v |= buswidth << CTRL_BPW_SHIFT;
|
||||||
|
writel(v, &pic32s->regs->ctrl);
|
||||||
|
|
||||||
|
/* re-configure dma width, if required */
|
||||||
|
if (test_bit(PIC32F_DMA_PREP, &pic32s->flags))
|
||||||
|
pic32_spi_dma_config(pic32s, dmawidth);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_prepare_hardware(struct spi_master *master)
|
||||||
|
{
|
||||||
|
struct pic32_spi *pic32s = spi_master_get_devdata(master);
|
||||||
|
|
||||||
|
pic32_spi_enable(pic32s);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_prepare_message(struct spi_master *master,
|
||||||
|
struct spi_message *msg)
|
||||||
|
{
|
||||||
|
struct pic32_spi *pic32s = spi_master_get_devdata(master);
|
||||||
|
struct spi_device *spi = msg->spi;
|
||||||
|
u32 val;
|
||||||
|
|
||||||
|
/* set device specific bits_per_word */
|
||||||
|
if (pic32s->bits_per_word != spi->bits_per_word) {
|
||||||
|
pic32_spi_set_word_size(pic32s, spi->bits_per_word);
|
||||||
|
pic32s->bits_per_word = spi->bits_per_word;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* device specific speed change */
|
||||||
|
if (pic32s->speed_hz != spi->max_speed_hz) {
|
||||||
|
pic32_spi_set_clk_rate(pic32s, spi->max_speed_hz);
|
||||||
|
pic32s->speed_hz = spi->max_speed_hz;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* device specific mode change */
|
||||||
|
if (pic32s->mode != spi->mode) {
|
||||||
|
val = readl(&pic32s->regs->ctrl);
|
||||||
|
/* active low */
|
||||||
|
if (spi->mode & SPI_CPOL)
|
||||||
|
val |= CTRL_CKP;
|
||||||
|
else
|
||||||
|
val &= ~CTRL_CKP;
|
||||||
|
/* tx on rising edge */
|
||||||
|
if (spi->mode & SPI_CPHA)
|
||||||
|
val &= ~CTRL_CKE;
|
||||||
|
else
|
||||||
|
val |= CTRL_CKE;
|
||||||
|
|
||||||
|
/* rx at end of tx */
|
||||||
|
val |= CTRL_SMP;
|
||||||
|
writel(val, &pic32s->regs->ctrl);
|
||||||
|
pic32s->mode = spi->mode;
|
||||||
|
}
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static bool pic32_spi_can_dma(struct spi_master *master,
|
||||||
|
struct spi_device *spi,
|
||||||
|
struct spi_transfer *xfer)
|
||||||
|
{
|
||||||
|
struct pic32_spi *pic32s = spi_master_get_devdata(master);
|
||||||
|
|
||||||
|
/* skip using DMA on small size transfer to avoid overhead.*/
|
||||||
|
return (xfer->len >= PIC32_DMA_LEN_MIN) &&
|
||||||
|
test_bit(PIC32F_DMA_PREP, &pic32s->flags);
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_one_transfer(struct spi_master *master,
|
||||||
|
struct spi_device *spi,
|
||||||
|
struct spi_transfer *transfer)
|
||||||
|
{
|
||||||
|
struct pic32_spi *pic32s;
|
||||||
|
bool dma_issued = false;
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
pic32s = spi_master_get_devdata(master);
|
||||||
|
|
||||||
|
/* handle transfer specific word size change */
|
||||||
|
if (transfer->bits_per_word &&
|
||||||
|
(transfer->bits_per_word != pic32s->bits_per_word)) {
|
||||||
|
ret = pic32_spi_set_word_size(pic32s, transfer->bits_per_word);
|
||||||
|
if (ret)
|
||||||
|
return ret;
|
||||||
|
pic32s->bits_per_word = transfer->bits_per_word;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* handle transfer specific speed change */
|
||||||
|
if (transfer->speed_hz && (transfer->speed_hz != pic32s->speed_hz)) {
|
||||||
|
pic32_spi_set_clk_rate(pic32s, transfer->speed_hz);
|
||||||
|
pic32s->speed_hz = transfer->speed_hz;
|
||||||
|
}
|
||||||
|
|
||||||
|
reinit_completion(&pic32s->xfer_done);
|
||||||
|
|
||||||
|
/* transact by DMA mode */
|
||||||
|
if (transfer->rx_sg.nents && transfer->tx_sg.nents) {
|
||||||
|
ret = pic32_spi_dma_transfer(pic32s, transfer);
|
||||||
|
if (ret) {
|
||||||
|
dev_err(&spi->dev, "dma submit error\n");
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* DMA issued */
|
||||||
|
dma_issued = true;
|
||||||
|
} else {
|
||||||
|
/* set current transfer information */
|
||||||
|
pic32s->tx = (const void *)transfer->tx_buf;
|
||||||
|
pic32s->rx = (const void *)transfer->rx_buf;
|
||||||
|
pic32s->tx_end = pic32s->tx + transfer->len;
|
||||||
|
pic32s->rx_end = pic32s->rx + transfer->len;
|
||||||
|
pic32s->len = transfer->len;
|
||||||
|
|
||||||
|
/* transact by interrupt driven PIO */
|
||||||
|
enable_irq(pic32s->fault_irq);
|
||||||
|
enable_irq(pic32s->rx_irq);
|
||||||
|
enable_irq(pic32s->tx_irq);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* wait for completion */
|
||||||
|
ret = wait_for_completion_timeout(&pic32s->xfer_done, 2 * HZ);
|
||||||
|
if (ret <= 0) {
|
||||||
|
dev_err(&spi->dev, "wait error/timedout\n");
|
||||||
|
if (dma_issued) {
|
||||||
|
dmaengine_terminate_all(master->dma_rx);
|
||||||
|
dmaengine_terminate_all(master->dma_rx);
|
||||||
|
}
|
||||||
|
ret = -ETIMEDOUT;
|
||||||
|
} else {
|
||||||
|
ret = 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_unprepare_message(struct spi_master *master,
|
||||||
|
struct spi_message *msg)
|
||||||
|
{
|
||||||
|
/* nothing to do */
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_unprepare_hardware(struct spi_master *master)
|
||||||
|
{
|
||||||
|
struct pic32_spi *pic32s = spi_master_get_devdata(master);
|
||||||
|
|
||||||
|
pic32_spi_disable(pic32s);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* This may be called multiple times by same spi dev */
|
||||||
|
static int pic32_spi_setup(struct spi_device *spi)
|
||||||
|
{
|
||||||
|
if (!spi->max_speed_hz) {
|
||||||
|
dev_err(&spi->dev, "No max speed HZ parameter\n");
|
||||||
|
return -EINVAL;
|
||||||
|
}
|
||||||
|
|
||||||
|
switch (spi->bits_per_word) {
|
||||||
|
case 8:
|
||||||
|
case 16:
|
||||||
|
case 32:
|
||||||
|
break;
|
||||||
|
default:
|
||||||
|
dev_err(&spi->dev, "Invalid bits_per_word defined\n");
|
||||||
|
return -EINVAL;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* PIC32 spi controller can drive /CS during transfer depending
|
||||||
|
* on tx fifo fill-level. /CS will stay asserted as long as TX
|
||||||
|
* fifo is non-empty, else will be deasserted indicating
|
||||||
|
* completion of the ongoing transfer. This might result into
|
||||||
|
* unreliable/erroneous SPI transactions.
|
||||||
|
* To avoid that we will always handle /CS by toggling GPIO.
|
||||||
|
*/
|
||||||
|
if (!gpio_is_valid(spi->cs_gpio))
|
||||||
|
return -EINVAL;
|
||||||
|
|
||||||
|
gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static void pic32_spi_cleanup(struct spi_device *spi)
|
||||||
|
{
|
||||||
|
/* de-activate cs-gpio */
|
||||||
|
gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
|
||||||
|
}
|
||||||
|
|
||||||
|
static void pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
|
||||||
|
{
|
||||||
|
struct spi_master *master = pic32s->master;
|
||||||
|
dma_cap_mask_t mask;
|
||||||
|
|
||||||
|
dma_cap_zero(mask);
|
||||||
|
dma_cap_set(DMA_SLAVE, mask);
|
||||||
|
|
||||||
|
master->dma_rx = dma_request_slave_channel_compat(mask, NULL, NULL,
|
||||||
|
dev, "spi-rx");
|
||||||
|
if (!master->dma_rx) {
|
||||||
|
dev_warn(dev, "RX channel not found.\n");
|
||||||
|
goto out_err;
|
||||||
|
}
|
||||||
|
|
||||||
|
master->dma_tx = dma_request_slave_channel_compat(mask, NULL, NULL,
|
||||||
|
dev, "spi-tx");
|
||||||
|
if (!master->dma_tx) {
|
||||||
|
dev_warn(dev, "TX channel not found.\n");
|
||||||
|
goto out_err;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (pic32_spi_dma_config(pic32s, DMA_SLAVE_BUSWIDTH_1_BYTE))
|
||||||
|
goto out_err;
|
||||||
|
|
||||||
|
/* DMA chnls allocated and prepared */
|
||||||
|
set_bit(PIC32F_DMA_PREP, &pic32s->flags);
|
||||||
|
|
||||||
|
return;
|
||||||
|
|
||||||
|
out_err:
|
||||||
|
if (master->dma_rx)
|
||||||
|
dma_release_channel(master->dma_rx);
|
||||||
|
|
||||||
|
if (master->dma_tx)
|
||||||
|
dma_release_channel(master->dma_tx);
|
||||||
|
}
|
||||||
|
|
||||||
|
static void pic32_spi_dma_unprep(struct pic32_spi *pic32s)
|
||||||
|
{
|
||||||
|
if (!test_bit(PIC32F_DMA_PREP, &pic32s->flags))
|
||||||
|
return;
|
||||||
|
|
||||||
|
clear_bit(PIC32F_DMA_PREP, &pic32s->flags);
|
||||||
|
if (pic32s->master->dma_rx)
|
||||||
|
dma_release_channel(pic32s->master->dma_rx);
|
||||||
|
|
||||||
|
if (pic32s->master->dma_tx)
|
||||||
|
dma_release_channel(pic32s->master->dma_tx);
|
||||||
|
}
|
||||||
|
|
||||||
|
static void pic32_spi_hw_init(struct pic32_spi *pic32s)
|
||||||
|
{
|
||||||
|
u32 ctrl;
|
||||||
|
|
||||||
|
/* disable hardware */
|
||||||
|
pic32_spi_disable(pic32s);
|
||||||
|
|
||||||
|
ctrl = readl(&pic32s->regs->ctrl);
|
||||||
|
/* enable enhanced fifo of 128bit deep */
|
||||||
|
ctrl |= CTRL_ENHBUF;
|
||||||
|
pic32s->fifo_n_byte = 16;
|
||||||
|
|
||||||
|
/* disable framing mode */
|
||||||
|
ctrl &= ~CTRL_FRMEN;
|
||||||
|
|
||||||
|
/* enable master mode while disabled */
|
||||||
|
ctrl |= CTRL_MSTEN;
|
||||||
|
|
||||||
|
/* set tx fifo threshold interrupt */
|
||||||
|
ctrl &= ~(0x3 << CTRL_TX_INT_SHIFT);
|
||||||
|
ctrl |= (TX_FIFO_HALF_EMPTY << CTRL_TX_INT_SHIFT);
|
||||||
|
|
||||||
|
/* set rx fifo threshold interrupt */
|
||||||
|
ctrl &= ~(0x3 << CTRL_RX_INT_SHIFT);
|
||||||
|
ctrl |= (RX_FIFO_NOT_EMPTY << CTRL_RX_INT_SHIFT);
|
||||||
|
|
||||||
|
/* select clk source */
|
||||||
|
ctrl &= ~CTRL_MCLKSEL;
|
||||||
|
|
||||||
|
/* set manual /CS mode */
|
||||||
|
ctrl &= ~CTRL_MSSEN;
|
||||||
|
|
||||||
|
writel(ctrl, &pic32s->regs->ctrl);
|
||||||
|
|
||||||
|
/* enable error reporting */
|
||||||
|
ctrl = CTRL2_TX_UR_EN | CTRL2_RX_OV_EN | CTRL2_FRM_ERR_EN;
|
||||||
|
writel(ctrl, &pic32s->regs->ctrl2_set);
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_hw_probe(struct platform_device *pdev,
|
||||||
|
struct pic32_spi *pic32s)
|
||||||
|
{
|
||||||
|
struct resource *mem;
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||||
|
pic32s->regs = devm_ioremap_resource(&pdev->dev, mem);
|
||||||
|
if (!pic32s->regs) {
|
||||||
|
dev_err(&pdev->dev, "ioremap() failed\n");
|
||||||
|
return -ENOMEM;
|
||||||
|
}
|
||||||
|
pic32s->dma_base = mem->start;
|
||||||
|
|
||||||
|
/* get irq resources: err-irq, rx-irq, tx-irq */
|
||||||
|
pic32s->fault_irq = platform_get_irq_byname(pdev, "fault");
|
||||||
|
if (pic32s->fault_irq < 0) {
|
||||||
|
dev_err(&pdev->dev, "fault-irq not found\n");
|
||||||
|
return pic32s->fault_irq;
|
||||||
|
}
|
||||||
|
|
||||||
|
pic32s->rx_irq = platform_get_irq_byname(pdev, "rx");
|
||||||
|
if (pic32s->rx_irq < 0) {
|
||||||
|
dev_err(&pdev->dev, "rx-irq not found\n");
|
||||||
|
return pic32s->rx_irq;
|
||||||
|
}
|
||||||
|
|
||||||
|
pic32s->tx_irq = platform_get_irq_byname(pdev, "tx");
|
||||||
|
if (pic32s->tx_irq < 0) {
|
||||||
|
dev_err(&pdev->dev, "tx-irq not found\n");
|
||||||
|
return pic32s->tx_irq;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* get clock */
|
||||||
|
pic32s->clk = devm_clk_get(&pdev->dev, "mck0");
|
||||||
|
if (IS_ERR(pic32s->clk)) {
|
||||||
|
dev_err(&pdev->dev, "clk not found\n");
|
||||||
|
ret = PTR_ERR(pic32s->clk);
|
||||||
|
goto err_unmap_mem;
|
||||||
|
}
|
||||||
|
|
||||||
|
ret = clk_prepare_enable(pic32s->clk);
|
||||||
|
if (ret)
|
||||||
|
goto err_unmap_mem;
|
||||||
|
|
||||||
|
pic32_spi_hw_init(pic32s);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
|
||||||
|
err_unmap_mem:
|
||||||
|
dev_err(&pdev->dev, "%s failed, err %d\n", __func__, ret);
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_probe(struct platform_device *pdev)
|
||||||
|
{
|
||||||
|
struct spi_master *master;
|
||||||
|
struct pic32_spi *pic32s;
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
master = spi_alloc_master(&pdev->dev, sizeof(*pic32s));
|
||||||
|
if (!master)
|
||||||
|
return -ENOMEM;
|
||||||
|
|
||||||
|
pic32s = spi_master_get_devdata(master);
|
||||||
|
pic32s->master = master;
|
||||||
|
|
||||||
|
ret = pic32_spi_hw_probe(pdev, pic32s);
|
||||||
|
if (ret)
|
||||||
|
goto err_master;
|
||||||
|
|
||||||
|
master->dev.of_node = of_node_get(pdev->dev.of_node);
|
||||||
|
master->mode_bits = SPI_MODE_3 | SPI_MODE_0 | SPI_CS_HIGH;
|
||||||
|
master->num_chipselect = 1; /* single chip-select */
|
||||||
|
master->max_speed_hz = clk_get_rate(pic32s->clk);
|
||||||
|
master->setup = pic32_spi_setup;
|
||||||
|
master->cleanup = pic32_spi_cleanup;
|
||||||
|
master->flags = SPI_MASTER_MUST_TX | SPI_MASTER_MUST_RX;
|
||||||
|
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
|
||||||
|
master->transfer_one = pic32_spi_one_transfer;
|
||||||
|
master->prepare_message = pic32_spi_prepare_message;
|
||||||
|
master->unprepare_message = pic32_spi_unprepare_message;
|
||||||
|
master->prepare_transfer_hardware = pic32_spi_prepare_hardware;
|
||||||
|
master->unprepare_transfer_hardware = pic32_spi_unprepare_hardware;
|
||||||
|
|
||||||
|
/* optional DMA support */
|
||||||
|
pic32_spi_dma_prep(pic32s, &pdev->dev);
|
||||||
|
if (test_bit(PIC32F_DMA_PREP, &pic32s->flags))
|
||||||
|
master->can_dma = pic32_spi_can_dma;
|
||||||
|
|
||||||
|
init_completion(&pic32s->xfer_done);
|
||||||
|
pic32s->mode = -1;
|
||||||
|
|
||||||
|
/* install irq handlers (with irq-disabled) */
|
||||||
|
irq_set_status_flags(pic32s->fault_irq, IRQ_NOAUTOEN);
|
||||||
|
ret = devm_request_irq(&pdev->dev, pic32s->fault_irq,
|
||||||
|
pic32_spi_fault_irq, IRQF_NO_THREAD,
|
||||||
|
dev_name(&pdev->dev), pic32s);
|
||||||
|
if (ret < 0) {
|
||||||
|
dev_err(&pdev->dev, "request fault-irq %d\n", pic32s->rx_irq);
|
||||||
|
goto err_bailout;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* receive interrupt handler */
|
||||||
|
irq_set_status_flags(pic32s->rx_irq, IRQ_NOAUTOEN);
|
||||||
|
ret = devm_request_irq(&pdev->dev, pic32s->rx_irq,
|
||||||
|
pic32_spi_rx_irq, IRQF_NO_THREAD,
|
||||||
|
dev_name(&pdev->dev), pic32s);
|
||||||
|
if (ret < 0) {
|
||||||
|
dev_err(&pdev->dev, "request rx-irq %d\n", pic32s->rx_irq);
|
||||||
|
goto err_bailout;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* transmit interrupt handler */
|
||||||
|
irq_set_status_flags(pic32s->tx_irq, IRQ_NOAUTOEN);
|
||||||
|
ret = devm_request_irq(&pdev->dev, pic32s->tx_irq,
|
||||||
|
pic32_spi_tx_irq, IRQF_NO_THREAD,
|
||||||
|
dev_name(&pdev->dev), pic32s);
|
||||||
|
if (ret < 0) {
|
||||||
|
dev_err(&pdev->dev, "request tx-irq %d\n", pic32s->tx_irq);
|
||||||
|
goto err_bailout;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* register master */
|
||||||
|
ret = devm_spi_register_master(&pdev->dev, master);
|
||||||
|
if (ret) {
|
||||||
|
dev_err(&master->dev, "failed registering spi master\n");
|
||||||
|
goto err_bailout;
|
||||||
|
}
|
||||||
|
|
||||||
|
platform_set_drvdata(pdev, pic32s);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
|
||||||
|
err_bailout:
|
||||||
|
clk_disable_unprepare(pic32s->clk);
|
||||||
|
err_master:
|
||||||
|
spi_master_put(master);
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int pic32_spi_remove(struct platform_device *pdev)
|
||||||
|
{
|
||||||
|
struct pic32_spi *pic32s;
|
||||||
|
|
||||||
|
pic32s = platform_get_drvdata(pdev);
|
||||||
|
pic32_spi_disable(pic32s);
|
||||||
|
clk_disable_unprepare(pic32s->clk);
|
||||||
|
pic32_spi_dma_unprep(pic32s);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static const struct of_device_id pic32_spi_of_match[] = {
|
||||||
|
{.compatible = "microchip,pic32mzda-spi",},
|
||||||
|
{},
|
||||||
|
};
|
||||||
|
MODULE_DEVICE_TABLE(of, pic32_spi_of_match);
|
||||||
|
|
||||||
|
static struct platform_driver pic32_spi_driver = {
|
||||||
|
.driver = {
|
||||||
|
.name = "spi-pic32",
|
||||||
|
.of_match_table = of_match_ptr(pic32_spi_of_match),
|
||||||
|
},
|
||||||
|
.probe = pic32_spi_probe,
|
||||||
|
.remove = pic32_spi_remove,
|
||||||
|
};
|
||||||
|
|
||||||
|
module_platform_driver(pic32_spi_driver);
|
||||||
|
|
||||||
|
MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@microchip.com>");
|
||||||
|
MODULE_DESCRIPTION("Microchip SPI driver for PIC32 SPI controller.");
|
||||||
|
MODULE_LICENSE("GPL v2");
|
||||||
Loading…
Reference in New Issue