spi:Add Freescale DSPI driver for Vybrid VF610 platform

The serial peripheral interface (SPI) module implemented on Freescale Vybrid
platform provides a synchronous serial bus for communication between Vybrid
and the external peripheral device.
The SPI supports full-duplex, three-wire synchronous transfer, has TX/RX FIFO
with depth of four entries.

This driver is the SPI master mode driver and has been tested on Vybrid
VF610TWR board.

Signed-off-by: Alison Wang <b18965@freescale.com>
Signed-off-by: Chao Fu  <b44548@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

3 files changed, 565 insertions, 0 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 89cbbabaff4..b9da6509c5e 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -248,6 +248,13 @@ config SPI_FSL_SPI
 	  This also enables using the Aeroflex Gaisler GRLIB SPI controller in
 	  master mode.
 
+config SPI_FSL_DSPI
+	tristate "Freescale DSPI controller"
+	select SPI_BITBANG
+	help
+	  This enables support for the Freescale DSPI controller in master
+	  mode. VF610 platform uses the controller.
+
 config SPI_FSL_ESPI
 	bool "Freescale eSPI controller"
 	depends on FSL_SOC
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 33f9c09561e..3441e0da405 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -30,6 +30,7 @@ spi-dw-midpci-objs			:= spi-dw-pci.o spi-dw-mid.o
 obj-$(CONFIG_SPI_EP93XX)		+= spi-ep93xx.o
 obj-$(CONFIG_SPI_FALCON)		+= spi-falcon.o
 obj-$(CONFIG_SPI_FSL_CPM)		+= spi-fsl-cpm.o
+obj-$(CONFIG_SPI_FSL_DSPI)		+= spi-fsl-dspi.o
 obj-$(CONFIG_SPI_FSL_LIB)		+= spi-fsl-lib.o
 obj-$(CONFIG_SPI_FSL_ESPI)		+= spi-fsl-espi.o
 obj-$(CONFIG_SPI_FSL_SPI)		+= spi-fsl-spi.o
diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
new file mode 100644
index 00000000000..6cd07d13eca
--- /dev/null
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -0,0 +1,557 @@
+/*
+ * drivers/spi/spi-fsl-dspi.c
+ *
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * Freescale DSPI driver
+ * This file contains a driver for the Freescale DSPI
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#define DRIVER_NAME "fsl-dspi"
+
+#define TRAN_STATE_RX_VOID		0x01
+#define TRAN_STATE_TX_VOID		0x02
+#define TRAN_STATE_WORD_ODD_NUM	0x04
+
+#define DSPI_FIFO_SIZE			4
+
+#define SPI_MCR		0x00
+#define SPI_MCR_MASTER		(1 << 31)
+#define SPI_MCR_PCSIS		(0x3F << 16)
+#define SPI_MCR_CLR_TXF	(1 << 11)
+#define SPI_MCR_CLR_RXF	(1 << 10)
+
+#define SPI_TCR			0x08
+
+#define SPI_CTAR(x)		(0x0c + (x * 4))
+#define SPI_CTAR_FMSZ(x)	(((x) & 0x0000000f) << 27)
+#define SPI_CTAR_CPOL(x)	((x) << 26)
+#define SPI_CTAR_CPHA(x)	((x) << 25)
+#define SPI_CTAR_LSBFE(x)	((x) << 24)
+#define SPI_CTAR_PCSSCR(x)	(((x) & 0x00000003) << 22)
+#define SPI_CTAR_PASC(x)	(((x) & 0x00000003) << 20)
+#define SPI_CTAR_PDT(x)	(((x) & 0x00000003) << 18)
+#define SPI_CTAR_PBR(x)	(((x) & 0x00000003) << 16)
+#define SPI_CTAR_CSSCK(x)	(((x) & 0x0000000f) << 12)
+#define SPI_CTAR_ASC(x)	(((x) & 0x0000000f) << 8)
+#define SPI_CTAR_DT(x)		(((x) & 0x0000000f) << 4)
+#define SPI_CTAR_BR(x)		((x) & 0x0000000f)
+
+#define SPI_CTAR0_SLAVE	0x0c
+
+#define SPI_SR			0x2c
+#define SPI_SR_EOQF		0x10000000
+
+#define SPI_RSER		0x30
+#define SPI_RSER_EOQFE		0x10000000
+
+#define SPI_PUSHR		0x34
+#define SPI_PUSHR_CONT		(1 << 31)
+#define SPI_PUSHR_CTAS(x)	(((x) & 0x00000007) << 28)
+#define SPI_PUSHR_EOQ		(1 << 27)
+#define SPI_PUSHR_CTCNT	(1 << 26)
+#define SPI_PUSHR_PCS(x)	(((1 << x) & 0x0000003f) << 16)
+#define SPI_PUSHR_TXDATA(x)	((x) & 0x0000ffff)
+
+#define SPI_PUSHR_SLAVE	0x34
+
+#define SPI_POPR		0x38
+#define SPI_POPR_RXDATA(x)	((x) & 0x0000ffff)
+
+#define SPI_TXFR0		0x3c
+#define SPI_TXFR1		0x40
+#define SPI_TXFR2		0x44
+#define SPI_TXFR3		0x48
+#define SPI_RXFR0		0x7c
+#define SPI_RXFR1		0x80
+#define SPI_RXFR2		0x84
+#define SPI_RXFR3		0x88
+
+#define SPI_FRAME_BITS(bits)	SPI_CTAR_FMSZ((bits) - 1)
+#define SPI_FRAME_BITS_MASK	SPI_CTAR_FMSZ(0xf)
+#define SPI_FRAME_BITS_16	SPI_CTAR_FMSZ(0xf)
+#define SPI_FRAME_BITS_8	SPI_CTAR_FMSZ(0x7)
+
+#define SPI_CS_INIT		0x01
+#define SPI_CS_ASSERT		0x02
+#define SPI_CS_DROP		0x04
+
+struct chip_data {
+	u32 mcr_val;
+	u32 ctar_val;
+	u16 void_write_data;
+};
+
+struct fsl_dspi {
+	struct spi_bitbang	bitbang;
+	struct platform_device	*pdev;
+
+	void			*base;
+	int			irq;
+	struct clk 		*clk;
+
+	struct spi_transfer 	*cur_transfer;
+	struct chip_data	*cur_chip;
+	size_t			len;
+	void			*tx;
+	void			*tx_end;
+	void			*rx;
+	void			*rx_end;
+	char			dataflags;
+	u8			cs;
+	u16			void_write_data;
+
+	wait_queue_head_t 	waitq;
+	u32 			waitflags;
+};
+
+static inline int is_double_byte_mode(struct fsl_dspi *dspi)
+{
+	return ((readl(dspi->base + SPI_CTAR(dspi->cs)) & SPI_FRAME_BITS_MASK)
+			== SPI_FRAME_BITS(8)) ? 0 : 1;
+}
+
+static void set_bit_mode(struct fsl_dspi *dspi, unsigned char bits)
+{
+	u32 temp;
+
+	temp = readl(dspi->base + SPI_CTAR(dspi->cs));
+	temp &= ~SPI_FRAME_BITS_MASK;
+	temp |= SPI_FRAME_BITS(bits);
+	writel(temp, dspi->base + SPI_CTAR(dspi->cs));
+}
+
+static void hz_to_spi_baud(char *pbr, char *br, int speed_hz,
+		unsigned long clkrate)
+{
+	/* Valid baud rate pre-scaler values */
+	int pbr_tbl[4] = {2, 3, 5, 7};
+	int brs[16] = {	2,	4,	6,	8,
+		16,	32,	64,	128,
+		256,	512,	1024,	2048,
+		4096,	8192,	16384,	32768 };
+	int temp, i = 0, j = 0;
+
+	temp = clkrate / 2 / speed_hz;
+
+	for (i = 0; i < ARRAY_SIZE(pbr_tbl); i++)
+		for (j = 0; j < ARRAY_SIZE(brs); j++) {
+			if (pbr_tbl[i] * brs[j] >= temp) {
+				*pbr = i;
+				*br = j;
+				return;
+			}
+		}
+
+	pr_warn("Can not find valid buad rate,speed_hz is %d,clkrate is %ld\
+		,we use the max prescaler value.\n", speed_hz, clkrate);
+	*pbr = ARRAY_SIZE(pbr_tbl) - 1;
+	*br =  ARRAY_SIZE(brs) - 1;
+}
+
+static int dspi_transfer_write(struct fsl_dspi *dspi)
+{
+	int tx_count = 0;
+	int tx_word;
+	u16 d16;
+	u8  d8;
+	u32 dspi_pushr = 0;
+	int first = 1;
+
+	tx_word = is_double_byte_mode(dspi);
+
+	/* If we are in word mode, but only have a single byte to transfer
+	 * then switch to byte mode temporarily.  Will switch back at the
+	 * end of the transfer.
+	 */
+	if (tx_word && (dspi->len == 1)) {
+		dspi->dataflags |= TRAN_STATE_WORD_ODD_NUM;
+		set_bit_mode(dspi, 8);
+		tx_word = 0;
+	}
+
+	while (dspi->len && (tx_count < DSPI_FIFO_SIZE)) {
+		if (tx_word) {
+			if (dspi->len == 1)
+				break;
+
+			if (!(dspi->dataflags & TRAN_STATE_TX_VOID)) {
+				d16 = *(u16 *)dspi->tx;
+				dspi->tx += 2;
+			} else {
+				d16 = dspi->void_write_data;
+			}
+
+			dspi_pushr = SPI_PUSHR_TXDATA(d16) |
+				SPI_PUSHR_PCS(dspi->cs) |
+				SPI_PUSHR_CTAS(dspi->cs) |
+				SPI_PUSHR_CONT;
+
+			dspi->len -= 2;
+		} else {
+			if (!(dspi->dataflags & TRAN_STATE_TX_VOID)) {
+
+				d8 = *(u8 *)dspi->tx;
+				dspi->tx++;
+			} else {
+				d8 = (u8)dspi->void_write_data;
+			}
+
+			dspi_pushr = SPI_PUSHR_TXDATA(d8) |
+				SPI_PUSHR_PCS(dspi->cs) |
+				SPI_PUSHR_CTAS(dspi->cs) |
+				SPI_PUSHR_CONT;
+
+			dspi->len--;
+		}
+
+		if (dspi->len == 0 || tx_count == DSPI_FIFO_SIZE - 1) {
+			/* last transfer in the transfer */
+			dspi_pushr |= SPI_PUSHR_EOQ;
+		} else if (tx_word && (dspi->len == 1))
+			dspi_pushr |= SPI_PUSHR_EOQ;
+
+		if (first) {
+			first = 0;
+			dspi_pushr |= SPI_PUSHR_CTCNT; /* clear counter */
+		}
+
+		writel(dspi_pushr, dspi->base + SPI_PUSHR);
+		tx_count++;
+	}
+
+	return tx_count * (tx_word + 1);
+}
+
+static int dspi_transfer_read(struct fsl_dspi *dspi)
+{
+	int rx_count = 0;
+	int rx_word = is_double_byte_mode(dspi);
+	u16 d;
+	while ((dspi->rx < dspi->rx_end)
+			&& (rx_count < DSPI_FIFO_SIZE)) {
+		if (rx_word) {
+			if ((dspi->rx_end - dspi->rx) == 1)
+				break;
+
+			d = SPI_POPR_RXDATA(readl(dspi->base + SPI_POPR));
+
+			if (!(dspi->dataflags & TRAN_STATE_RX_VOID))
+				*(u16 *)dspi->rx = d;
+			dspi->rx += 2;
+
+		} else {
+			d = SPI_POPR_RXDATA(readl(dspi->base + SPI_POPR));
+			if (!(dspi->dataflags & TRAN_STATE_RX_VOID))
+				*(u8 *)dspi->rx = d;
+			dspi->rx++;
+		}
+		rx_count++;
+	}
+
+	return rx_count;
+}
+
+static int dspi_txrx_transfer(struct spi_device *spi, struct spi_transfer *t)
+{
+	struct fsl_dspi *dspi = spi_master_get_devdata(spi->master);
+	dspi->cur_transfer = t;
+	dspi->cur_chip = spi_get_ctldata(spi);
+	dspi->cs = spi->chip_select;
+	dspi->void_write_data = dspi->cur_chip->void_write_data;
+
+	dspi->dataflags = 0;
+	dspi->tx = (void *)t->tx_buf;
+	dspi->tx_end = dspi->tx + t->len;
+	dspi->rx = t->rx_buf;
+	dspi->rx_end = dspi->rx + t->len;
+	dspi->len = t->len;
+
+	if (!dspi->rx)
+		dspi->dataflags |= TRAN_STATE_RX_VOID;
+
+	if (!dspi->tx)
+		dspi->dataflags |= TRAN_STATE_TX_VOID;
+
+	writel(dspi->cur_chip->mcr_val, dspi->base + SPI_MCR);
+	writel(dspi->cur_chip->ctar_val, dspi->base + SPI_CTAR(dspi->cs));
+	writel(SPI_RSER_EOQFE, dspi->base + SPI_RSER);
+
+	if (t->speed_hz)
+		writel(dspi->cur_chip->ctar_val,
+				dspi->base + SPI_CTAR(dspi->cs));
+
+	dspi_transfer_write(dspi);
+
+	if (wait_event_interruptible(dspi->waitq, dspi->waitflags))
+		dev_err(&dspi->pdev->dev, "wait transfer complete fail!\n");
+	dspi->waitflags = 0;
+
+	return t->len - dspi->len;
+}
+
+static void dspi_chipselect(struct spi_device *spi, int value)
+{
+	struct fsl_dspi *dspi = spi_master_get_devdata(spi->master);
+	u32 pushr = readl(dspi->base + SPI_PUSHR);
+
+	switch (value) {
+	case BITBANG_CS_ACTIVE:
+		pushr |= SPI_PUSHR_CONT;
+	case BITBANG_CS_INACTIVE:
+		pushr &= ~SPI_PUSHR_CONT;
+	}
+
+	writel(pushr, dspi->base + SPI_PUSHR);
+}
+
+static int dspi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
+{
+	struct chip_data *chip;
+	struct fsl_dspi *dspi = spi_master_get_devdata(spi->master);
+	unsigned char br = 0, pbr = 0, fmsz = 0;
+
+	/* Only alloc on first setup */
+	chip = spi_get_ctldata(spi);
+	if (chip == NULL) {
+		chip = kcalloc(1, sizeof(struct chip_data), GFP_KERNEL);
+		if (!chip)
+			return -ENOMEM;
+	}
+
+	chip->mcr_val = SPI_MCR_MASTER | SPI_MCR_PCSIS |
+		SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF;
+	if ((spi->bits_per_word >= 4) && (spi->bits_per_word <= 16)) {
+		fmsz = spi->bits_per_word - 1;
+	} else {
+		pr_err("Invalid wordsize\n");
+		kfree(chip);
+		return -ENODEV;
+	}
+
+	chip->void_write_data = 0;
+
+	hz_to_spi_baud(&pbr, &br,
+			spi->max_speed_hz, clk_get_rate(dspi->clk));
+
+	chip->ctar_val =  SPI_CTAR_FMSZ(fmsz)
+		| SPI_CTAR_CPOL(spi->mode & SPI_CPOL ? 1 : 0)
+		| SPI_CTAR_CPHA(spi->mode & SPI_CPHA ? 1 : 0)
+		| SPI_CTAR_LSBFE(spi->mode & SPI_LSB_FIRST ? 1 : 0)
+		| SPI_CTAR_PBR(pbr)
+		| SPI_CTAR_BR(br);
+
+	spi_set_ctldata(spi, chip);
+
+	return 0;
+}
+
+static int dspi_setup(struct spi_device *spi)
+{
+	if (!spi->max_speed_hz)
+		return -EINVAL;
+
+	if (!spi->bits_per_word)
+		spi->bits_per_word = 8;
+
+	return dspi_setup_transfer(spi, NULL);
+}
+
+static irqreturn_t dspi_interrupt(int irq, void *dev_id)
+{
+	struct fsl_dspi *dspi = (struct fsl_dspi *)dev_id;
+
+	writel(SPI_SR_EOQF, dspi->base + SPI_SR);
+
+	dspi_transfer_read(dspi);
+
+	if (!dspi->len) {
+		if (dspi->dataflags & TRAN_STATE_WORD_ODD_NUM)
+			set_bit_mode(dspi, 16);
+		dspi->waitflags = 1;
+		wake_up_interruptible(&dspi->waitq);
+	} else {
+		dspi_transfer_write(dspi);
+
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static struct of_device_id fsl_dspi_dt_ids[] = {
+	{ .compatible = "fsl,vf610-dspi", .data = NULL, },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, fsl_dspi_dt_ids);
+
+#ifdef CONFIG_PM_SLEEP
+static int dspi_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct fsl_dspi *dspi = spi_master_get_devdata(master);
+
+	spi_master_suspend(master);
+	clk_disable_unprepare(dspi->clk);
+
+	return 0;
+}
+
+static int dspi_resume(struct device *dev)
+{
+
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct fsl_dspi *dspi = spi_master_get_devdata(master);
+
+	clk_prepare_enable(dspi->clk);
+	spi_master_resume(master);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops dspi_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(dspi_suspend, dspi_resume)
+};
+
+static int dspi_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct spi_master *master;
+	struct fsl_dspi *dspi;
+	struct resource *res;
+	int ret = 0, cs_num, bus_num;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(struct fsl_dspi));
+	if (!master)
+		return -ENOMEM;
+
+	dspi = spi_master_get_devdata(master);
+	dspi->pdev = pdev;
+	dspi->bitbang.master = spi_master_get(master);
+	dspi->bitbang.chipselect = dspi_chipselect;
+	dspi->bitbang.setup_transfer = dspi_setup_transfer;
+	dspi->bitbang.txrx_bufs = dspi_txrx_transfer;
+	dspi->bitbang.master->setup = dspi_setup;
+	dspi->bitbang.master->dev.of_node = pdev->dev.of_node;
+
+	master->mode_bits = SPI_CPOL | SPI_CPHA;
+	master->bits_per_word_mask = SPI_BPW_MASK(4) | SPI_BPW_MASK(8) |
+					SPI_BPW_MASK(16);
+
+	ret = of_property_read_u32(np, "spi-num-chipselects", &cs_num);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "can't get spi-num-chipselects\n");
+		goto out_master_put;
+	}
+	master->num_chipselect = cs_num;
+
+	ret = of_property_read_u32(np, "bus-num", &bus_num);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "can't get bus-num\n");
+		goto out_master_put;
+	}
+	master->bus_num = bus_num;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "can't get platform resource\n");
+		ret = -EINVAL;
+		goto out_master_put;
+	}
+
+	dspi->base = devm_ioremap_resource(&pdev->dev, res);
+	if (!dspi->base) {
+		ret = -EINVAL;
+		goto out_master_put;
+	}
+
+	dspi->irq = platform_get_irq(pdev, 0);
+	if (dspi->irq < 0) {
+		dev_err(&pdev->dev, "can't get platform irq\n");
+		ret = dspi->irq;
+		goto out_master_put;
+	}
+
+	ret = devm_request_irq(&pdev->dev, dspi->irq, dspi_interrupt, 0,
+			pdev->name, dspi);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Unable to attach DSPI interrupt\n");
+		goto out_master_put;
+	}
+
+	dspi->clk = devm_clk_get(&pdev->dev, "dspi");
+	if (IS_ERR(dspi->clk)) {
+		ret = PTR_ERR(dspi->clk);
+		dev_err(&pdev->dev, "unable to get clock\n");
+		goto out_master_put;
+	}
+	clk_prepare_enable(dspi->clk);
+
+	init_waitqueue_head(&dspi->waitq);
+	platform_set_drvdata(pdev, dspi);
+
+	ret = spi_bitbang_start(&dspi->bitbang);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "Problem registering DSPI master\n");
+		goto out_clk_put;
+	}
+
+	pr_info(KERN_INFO "Freescale DSPI master initialized\n");
+	return ret;
+
+out_clk_put:
+	clk_disable_unprepare(dspi->clk);
+out_master_put:
+	spi_master_put(master);
+	platform_set_drvdata(pdev, NULL);
+
+	return ret;
+}
+
+static int dspi_remove(struct platform_device *pdev)
+{
+	struct fsl_dspi *dspi = platform_get_drvdata(pdev);
+
+	/* Disconnect from the SPI framework */
+	spi_bitbang_stop(&dspi->bitbang);
+	spi_master_put(dspi->bitbang.master);
+
+	return 0;
+}
+
+static struct platform_driver fsl_dspi_driver = {
+	.driver.name    = DRIVER_NAME,
+	.driver.of_match_table = fsl_dspi_dt_ids,
+	.driver.owner   = THIS_MODULE,
+	.driver.pm = &dspi_pm,
+	.probe          = dspi_probe,
+	.remove		= dspi_remove,
+};
+module_platform_driver(fsl_dspi_driver);
+
+MODULE_DESCRIPTION("Freescale DSPI Controller Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);