434 lines
8.9 KiB
C
434 lines
8.9 KiB
C
/*
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* Copyright (c) 2009 Nuvoton technology.
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* Wan ZongShun <mcuos.com@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it 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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*/
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/device.h>
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#include <linux/platform_device.h>
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#include <linux/gpio.h>
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#include <linux/io.h>
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#include <linux/slab.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_bitbang.h>
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#include <linux/platform_data/spi-nuc900.h>
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/* usi registers offset */
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#define USI_CNT 0x00
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#define USI_DIV 0x04
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#define USI_SSR 0x08
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#define USI_RX0 0x10
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#define USI_TX0 0x10
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/* usi register bit */
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#define ENINT (0x01 << 17)
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#define ENFLG (0x01 << 16)
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#define SLEEP (0x0f << 12)
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#define TXNUM (0x03 << 8)
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#define TXBITLEN (0x1f << 3)
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#define TXNEG (0x01 << 2)
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#define RXNEG (0x01 << 1)
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#define LSB (0x01 << 10)
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#define SELECTLEV (0x01 << 2)
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#define SELECTPOL (0x01 << 31)
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#define SELECTSLAVE 0x01
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#define GOBUSY 0x01
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struct nuc900_spi {
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struct spi_bitbang bitbang;
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struct completion done;
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void __iomem *regs;
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int irq;
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int len;
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int count;
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const unsigned char *tx;
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unsigned char *rx;
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struct clk *clk;
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struct spi_master *master;
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struct nuc900_spi_info *pdata;
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spinlock_t lock;
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};
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static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
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{
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return spi_master_get_devdata(sdev->master);
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}
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static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
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{
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struct nuc900_spi *hw = to_hw(spi);
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unsigned int val;
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unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
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unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_SSR);
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if (!cs)
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val &= ~SELECTLEV;
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else
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val |= SELECTLEV;
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if (!ssr)
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val &= ~SELECTSLAVE;
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else
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val |= SELECTSLAVE;
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__raw_writel(val, hw->regs + USI_SSR);
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val = __raw_readl(hw->regs + USI_CNT);
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if (!cpol)
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val &= ~SELECTPOL;
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else
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val |= SELECTPOL;
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static void nuc900_spi_chipsel(struct spi_device *spi, int value)
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{
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switch (value) {
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case BITBANG_CS_INACTIVE:
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nuc900_slave_select(spi, 0);
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break;
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case BITBANG_CS_ACTIVE:
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nuc900_slave_select(spi, 1);
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break;
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}
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}
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static void nuc900_spi_setup_txnum(struct nuc900_spi *hw, unsigned int txnum)
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{
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unsigned int val;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_CNT) & ~TXNUM;
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if (txnum)
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val |= txnum << 0x08;
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
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unsigned int txbitlen)
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{
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unsigned int val;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_CNT) & ~TXBITLEN;
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val |= (txbitlen << 0x03);
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static void nuc900_spi_gobusy(struct nuc900_spi *hw)
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{
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unsigned int val;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_CNT);
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val |= GOBUSY;
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
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{
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return hw->tx ? hw->tx[count] : 0;
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}
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static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
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{
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struct nuc900_spi *hw = to_hw(spi);
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hw->tx = t->tx_buf;
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hw->rx = t->rx_buf;
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hw->len = t->len;
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hw->count = 0;
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__raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
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nuc900_spi_gobusy(hw);
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wait_for_completion(&hw->done);
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return hw->count;
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}
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static irqreturn_t nuc900_spi_irq(int irq, void *dev)
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{
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struct nuc900_spi *hw = dev;
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unsigned int status;
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unsigned int count = hw->count;
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status = __raw_readl(hw->regs + USI_CNT);
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__raw_writel(status, hw->regs + USI_CNT);
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if (status & ENFLG) {
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hw->count++;
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if (hw->rx)
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hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
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count++;
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if (count < hw->len) {
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__raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
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nuc900_spi_gobusy(hw);
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} else {
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complete(&hw->done);
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}
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return IRQ_HANDLED;
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}
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complete(&hw->done);
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return IRQ_HANDLED;
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}
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static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
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{
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unsigned int val;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_CNT);
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if (edge)
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val |= TXNEG;
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else
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val &= ~TXNEG;
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
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{
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unsigned int val;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_CNT);
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if (edge)
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val |= RXNEG;
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else
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val &= ~RXNEG;
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
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{
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unsigned int val;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_CNT);
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if (lsb)
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val |= LSB;
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else
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val &= ~LSB;
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
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{
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unsigned int val;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_CNT) & ~SLEEP;
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if (sleep)
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val |= (sleep << 12);
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static void nuc900_enable_int(struct nuc900_spi *hw)
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{
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unsigned int val;
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unsigned long flags;
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spin_lock_irqsave(&hw->lock, flags);
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val = __raw_readl(hw->regs + USI_CNT);
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val |= ENINT;
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__raw_writel(val, hw->regs + USI_CNT);
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spin_unlock_irqrestore(&hw->lock, flags);
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}
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static void nuc900_set_divider(struct nuc900_spi *hw)
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{
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__raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
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}
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static void nuc900_init_spi(struct nuc900_spi *hw)
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{
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clk_enable(hw->clk);
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spin_lock_init(&hw->lock);
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nuc900_tx_edge(hw, hw->pdata->txneg);
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nuc900_rx_edge(hw, hw->pdata->rxneg);
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nuc900_send_first(hw, hw->pdata->lsb);
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nuc900_set_sleep(hw, hw->pdata->sleep);
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nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
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nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
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nuc900_set_divider(hw);
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nuc900_enable_int(hw);
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}
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static int nuc900_spi_probe(struct platform_device *pdev)
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{
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struct nuc900_spi *hw;
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struct spi_master *master;
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struct resource *res;
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int err = 0;
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master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
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if (master == NULL) {
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dev_err(&pdev->dev, "No memory for spi_master\n");
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return -ENOMEM;
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}
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hw = spi_master_get_devdata(master);
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hw->master = master;
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hw->pdata = dev_get_platdata(&pdev->dev);
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if (hw->pdata == NULL) {
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dev_err(&pdev->dev, "No platform data supplied\n");
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err = -ENOENT;
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goto err_pdata;
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}
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platform_set_drvdata(pdev, hw);
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init_completion(&hw->done);
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master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
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if (hw->pdata->lsb)
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master->mode_bits |= SPI_LSB_FIRST;
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master->num_chipselect = hw->pdata->num_cs;
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master->bus_num = hw->pdata->bus_num;
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hw->bitbang.master = hw->master;
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hw->bitbang.chipselect = nuc900_spi_chipsel;
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hw->bitbang.txrx_bufs = nuc900_spi_txrx;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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hw->regs = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(hw->regs)) {
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err = PTR_ERR(hw->regs);
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goto err_pdata;
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}
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hw->irq = platform_get_irq(pdev, 0);
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if (hw->irq < 0) {
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dev_err(&pdev->dev, "No IRQ specified\n");
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err = -ENOENT;
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goto err_pdata;
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}
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err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
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pdev->name, hw);
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if (err) {
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dev_err(&pdev->dev, "Cannot claim IRQ\n");
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goto err_pdata;
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}
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hw->clk = devm_clk_get(&pdev->dev, "spi");
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if (IS_ERR(hw->clk)) {
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dev_err(&pdev->dev, "No clock for device\n");
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err = PTR_ERR(hw->clk);
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goto err_pdata;
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}
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mfp_set_groupg(&pdev->dev, NULL);
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nuc900_init_spi(hw);
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err = spi_bitbang_start(&hw->bitbang);
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if (err) {
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dev_err(&pdev->dev, "Failed to register SPI master\n");
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goto err_register;
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}
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return 0;
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err_register:
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clk_disable(hw->clk);
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err_pdata:
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spi_master_put(hw->master);
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return err;
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}
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static int nuc900_spi_remove(struct platform_device *dev)
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{
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struct nuc900_spi *hw = platform_get_drvdata(dev);
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spi_bitbang_stop(&hw->bitbang);
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clk_disable(hw->clk);
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spi_master_put(hw->master);
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return 0;
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}
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static struct platform_driver nuc900_spi_driver = {
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.probe = nuc900_spi_probe,
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.remove = nuc900_spi_remove,
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.driver = {
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.name = "nuc900-spi",
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},
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};
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module_platform_driver(nuc900_spi_driver);
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MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
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MODULE_DESCRIPTION("nuc900 spi driver!");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:nuc900-spi");
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