/* * Broadcom BCM63xx SPI controller support * * Copyright (C) 2009-2012 Florian Fainelli <florian@openwrt.org> * Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/clk.h> #include <linux/io.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/delay.h> #include <linux/interrupt.h> #include <linux/spi/spi.h> #include <linux/completion.h> #include <linux/err.h> #include <linux/workqueue.h> #include <linux/pm_runtime.h> #include <bcm63xx_dev_spi.h> #define PFX KBUILD_MODNAME #define BCM63XX_SPI_MAX_PREPEND 15 struct bcm63xx_spi { struct completion done; void __iomem *regs; int irq; /* Platform data */ unsigned fifo_size; unsigned int msg_type_shift; unsigned int msg_ctl_width; /* data iomem */ u8 __iomem *tx_io; const u8 __iomem *rx_io; struct clk *clk; struct platform_device *pdev; }; static inline u8 bcm_spi_readb(struct bcm63xx_spi *bs, unsigned int offset) { return bcm_readb(bs->regs + bcm63xx_spireg(offset)); } static inline u16 bcm_spi_readw(struct bcm63xx_spi *bs, unsigned int offset) { return bcm_readw(bs->regs + bcm63xx_spireg(offset)); } static inline void bcm_spi_writeb(struct bcm63xx_spi *bs, u8 value, unsigned int offset) { bcm_writeb(value, bs->regs + bcm63xx_spireg(offset)); } static inline void bcm_spi_writew(struct bcm63xx_spi *bs, u16 value, unsigned int offset) { bcm_writew(value, bs->regs + bcm63xx_spireg(offset)); } static const unsigned bcm63xx_spi_freq_table[SPI_CLK_MASK][2] = { { 20000000, SPI_CLK_20MHZ }, { 12500000, SPI_CLK_12_50MHZ }, { 6250000, SPI_CLK_6_250MHZ }, { 3125000, SPI_CLK_3_125MHZ }, { 1563000, SPI_CLK_1_563MHZ }, { 781000, SPI_CLK_0_781MHZ }, { 391000, SPI_CLK_0_391MHZ } }; static void bcm63xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) { struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master); u8 clk_cfg, reg; int i; /* Find the closest clock configuration */ for (i = 0; i < SPI_CLK_MASK; i++) { if (t->speed_hz >= bcm63xx_spi_freq_table[i][0]) { clk_cfg = bcm63xx_spi_freq_table[i][1]; break; } } /* No matching configuration found, default to lowest */ if (i == SPI_CLK_MASK) clk_cfg = SPI_CLK_0_391MHZ; /* clear existing clock configuration bits of the register */ reg = bcm_spi_readb(bs, SPI_CLK_CFG); reg &= ~SPI_CLK_MASK; reg |= clk_cfg; bcm_spi_writeb(bs, reg, SPI_CLK_CFG); dev_dbg(&spi->dev, "Setting clock register to %02x (hz %d)\n", clk_cfg, t->speed_hz); } /* the spi->mode bits understood by this driver: */ #define MODEBITS (SPI_CPOL | SPI_CPHA) static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *first, unsigned int num_transfers) { struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master); u16 msg_ctl; u16 cmd; u8 rx_tail; unsigned int i, timeout = 0, prepend_len = 0, len = 0; struct spi_transfer *t = first; bool do_rx = false; bool do_tx = false; /* Disable the CMD_DONE interrupt */ bcm_spi_writeb(bs, 0, SPI_INT_MASK); dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n", t->tx_buf, t->rx_buf, t->len); if (num_transfers > 1 && t->tx_buf && t->len <= BCM63XX_SPI_MAX_PREPEND) prepend_len = t->len; /* prepare the buffer */ for (i = 0; i < num_transfers; i++) { if (t->tx_buf) { do_tx = true; memcpy_toio(bs->tx_io + len, t->tx_buf, t->len); /* don't prepend more than one tx */ if (t != first) prepend_len = 0; } if (t->rx_buf) { do_rx = true; /* prepend is half-duplex write only */ if (t == first) prepend_len = 0; } len += t->len; t = list_entry(t->transfer_list.next, struct spi_transfer, transfer_list); } len -= prepend_len; init_completion(&bs->done); /* Fill in the Message control register */ msg_ctl = (len << SPI_BYTE_CNT_SHIFT); if (do_rx && do_tx && prepend_len == 0) msg_ctl |= (SPI_FD_RW << bs->msg_type_shift); else if (do_rx) msg_ctl |= (SPI_HD_R << bs->msg_type_shift); else if (do_tx) msg_ctl |= (SPI_HD_W << bs->msg_type_shift); switch (bs->msg_ctl_width) { case 8: bcm_spi_writeb(bs, msg_ctl, SPI_MSG_CTL); break; case 16: bcm_spi_writew(bs, msg_ctl, SPI_MSG_CTL); break; } /* Issue the transfer */ cmd = SPI_CMD_START_IMMEDIATE; cmd |= (prepend_len << SPI_CMD_PREPEND_BYTE_CNT_SHIFT); cmd |= (spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT); bcm_spi_writew(bs, cmd, SPI_CMD); /* Enable the CMD_DONE interrupt */ bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK); timeout = wait_for_completion_timeout(&bs->done, HZ); if (!timeout) return -ETIMEDOUT; /* read out all data */ rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL); if (do_rx && rx_tail != len) return -EIO; if (!rx_tail) return 0; len = 0; t = first; /* Read out all the data */ for (i = 0; i < num_transfers; i++) { if (t->rx_buf) memcpy_fromio(t->rx_buf, bs->rx_io + len, t->len); if (t != first || prepend_len == 0) len += t->len; t = list_entry(t->transfer_list.next, struct spi_transfer, transfer_list); } return 0; } static int bcm63xx_spi_transfer_one(struct spi_master *master, struct spi_message *m) { struct bcm63xx_spi *bs = spi_master_get_devdata(master); struct spi_transfer *t, *first = NULL; struct spi_device *spi = m->spi; int status = 0; unsigned int n_transfers = 0, total_len = 0; bool can_use_prepend = false; /* * This SPI controller does not support keeping CS active after a * transfer. * Work around this by merging as many transfers we can into one big * full-duplex transfers. */ list_for_each_entry(t, &m->transfers, transfer_list) { if (!first) first = t; n_transfers++; total_len += t->len; if (n_transfers == 2 && !first->rx_buf && !t->tx_buf && first->len <= BCM63XX_SPI_MAX_PREPEND) can_use_prepend = true; else if (can_use_prepend && t->tx_buf) can_use_prepend = false; /* we can only transfer one fifo worth of data */ if ((can_use_prepend && total_len > (bs->fifo_size + BCM63XX_SPI_MAX_PREPEND)) || (!can_use_prepend && total_len > bs->fifo_size)) { dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n", total_len, bs->fifo_size); status = -EINVAL; goto exit; } /* all combined transfers have to have the same speed */ if (t->speed_hz != first->speed_hz) { dev_err(&spi->dev, "unable to change speed between transfers\n"); status = -EINVAL; goto exit; } /* CS will be deasserted directly after transfer */ if (t->delay_usecs) { dev_err(&spi->dev, "unable to keep CS asserted after transfer\n"); status = -EINVAL; goto exit; } if (t->cs_change || list_is_last(&t->transfer_list, &m->transfers)) { /* configure adapter for a new transfer */ bcm63xx_spi_setup_transfer(spi, first); /* send the data */ status = bcm63xx_txrx_bufs(spi, first, n_transfers); if (status) goto exit; m->actual_length += total_len; first = NULL; n_transfers = 0; total_len = 0; can_use_prepend = false; } } exit: m->status = status; spi_finalize_current_message(master); return 0; } /* This driver supports single master mode only. Hence * CMD_DONE is the only interrupt we care about */ static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id) { struct spi_master *master = (struct spi_master *)dev_id; struct bcm63xx_spi *bs = spi_master_get_devdata(master); u8 intr; /* Read interupts and clear them immediately */ intr = bcm_spi_readb(bs, SPI_INT_STATUS); bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS); bcm_spi_writeb(bs, 0, SPI_INT_MASK); /* A transfer completed */ if (intr & SPI_INTR_CMD_DONE) complete(&bs->done); return IRQ_HANDLED; } static int bcm63xx_spi_probe(struct platform_device *pdev) { struct resource *r; struct device *dev = &pdev->dev; struct bcm63xx_spi_pdata *pdata = dev_get_platdata(&pdev->dev); int irq; struct spi_master *master; struct clk *clk; struct bcm63xx_spi *bs; int ret; irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(dev, "no irq\n"); ret = -ENXIO; goto out; } clk = clk_get(dev, "spi"); if (IS_ERR(clk)) { dev_err(dev, "no clock for device\n"); ret = PTR_ERR(clk); goto out; } master = spi_alloc_master(dev, sizeof(*bs)); if (!master) { dev_err(dev, "out of memory\n"); ret = -ENOMEM; goto out_clk; } bs = spi_master_get_devdata(master); platform_set_drvdata(pdev, master); bs->pdev = pdev; r = platform_get_resource(pdev, IORESOURCE_MEM, 0); bs->regs = devm_ioremap_resource(&pdev->dev, r); if (IS_ERR(bs->regs)) { ret = PTR_ERR(bs->regs); goto out_err; } bs->irq = irq; bs->clk = clk; bs->fifo_size = pdata->fifo_size; ret = devm_request_irq(&pdev->dev, irq, bcm63xx_spi_interrupt, 0, pdev->name, master); if (ret) { dev_err(dev, "unable to request irq\n"); goto out_err; } master->bus_num = pdata->bus_num; master->num_chipselect = pdata->num_chipselect; master->transfer_one_message = bcm63xx_spi_transfer_one; master->mode_bits = MODEBITS; master->bits_per_word_mask = SPI_BPW_MASK(8); master->auto_runtime_pm = true; bs->msg_type_shift = pdata->msg_type_shift; bs->msg_ctl_width = pdata->msg_ctl_width; bs->tx_io = (u8 *)(bs->regs + bcm63xx_spireg(SPI_MSG_DATA)); bs->rx_io = (const u8 *)(bs->regs + bcm63xx_spireg(SPI_RX_DATA)); switch (bs->msg_ctl_width) { case 8: case 16: break; default: dev_err(dev, "unsupported MSG_CTL width: %d\n", bs->msg_ctl_width); goto out_err; } /* Initialize hardware */ clk_prepare_enable(bs->clk); bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS); /* register and we are done */ ret = devm_spi_register_master(dev, master); if (ret) { dev_err(dev, "spi register failed\n"); goto out_clk_disable; } dev_info(dev, "at 0x%08x (irq %d, FIFOs size %d)\n", r->start, irq, bs->fifo_size); return 0; out_clk_disable: clk_disable_unprepare(clk); out_err: spi_master_put(master); out_clk: clk_put(clk); out: return ret; } static int bcm63xx_spi_remove(struct platform_device *pdev) { struct spi_master *master = platform_get_drvdata(pdev); struct bcm63xx_spi *bs = spi_master_get_devdata(master); /* reset spi block */ bcm_spi_writeb(bs, 0, SPI_INT_MASK); /* HW shutdown */ clk_disable_unprepare(bs->clk); clk_put(bs->clk); return 0; } #ifdef CONFIG_PM static int bcm63xx_spi_suspend(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct bcm63xx_spi *bs = spi_master_get_devdata(master); spi_master_suspend(master); clk_disable_unprepare(bs->clk); return 0; } static int bcm63xx_spi_resume(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct bcm63xx_spi *bs = spi_master_get_devdata(master); clk_prepare_enable(bs->clk); spi_master_resume(master); return 0; } static const struct dev_pm_ops bcm63xx_spi_pm_ops = { .suspend = bcm63xx_spi_suspend, .resume = bcm63xx_spi_resume, }; #define BCM63XX_SPI_PM_OPS (&bcm63xx_spi_pm_ops) #else #define BCM63XX_SPI_PM_OPS NULL #endif static struct platform_driver bcm63xx_spi_driver = { .driver = { .name = "bcm63xx-spi", .owner = THIS_MODULE, .pm = BCM63XX_SPI_PM_OPS, }, .probe = bcm63xx_spi_probe, .remove = bcm63xx_spi_remove, }; module_platform_driver(bcm63xx_spi_driver); MODULE_ALIAS("platform:bcm63xx_spi"); MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>"); MODULE_AUTHOR("Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>"); MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver"); MODULE_LICENSE("GPL");