Commit 349ad66c authored by Chao Fu's avatar Chao Fu Committed by Mark Brown
Browse files

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: default avatarAlison Wang <b18965@freescale.com>
Signed-off-by: default avatarChao Fu <b44548@freescale.com>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 9cbd72e5

drivers/spi/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -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

drivers/spi/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/spi/spi-fsl-dspi.c

0 → 100644
+557 −0
Original line number Diff line number Diff line 
/*

 * 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);

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