Commit 646781d3 authored by Marek Vasut's avatar Marek Vasut Committed by Mark Brown
Browse files

spi/mxs: Add SPI driver for mx233/mx28 



This is slightly reworked version of the SPI driver.
Support for DT has been added and it's been converted
to queued API.

Based on previous attempt by:
Fabio Estevam <fabio.estevam@freescale.com>

Signed-off-by: default avatarFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: default avatarMarek Vasut <marex@denx.de>
Acked-by: default avatarChris Ball <cjb@laptop.org>
Acked-by: default avatarShawn Guo <shawn.guo@linaro.org>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 13082398

drivers/spi/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -364,6 +364,13 @@ config SPI_STMP3XXX 
	help

	  SPI driver for Freescale STMP37xx/378x SoC SSP interface



config SPI_MXS

	tristate "Freescale MXS SPI controller"

	depends on ARCH_MXS

	select STMP_DEVICE

	help

	  SPI driver for Freescale MXS devices.



config SPI_TEGRA

	tristate "Nvidia Tegra SPI controller"

	depends on ARCH_TEGRA && (TEGRA_SYSTEM_DMA || TEGRA20_APB_DMA)

drivers/spi/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ obj-$(CONFIG_SPI_LM70_LLP) += spi-lm70llp.o 
obj-$(CONFIG_SPI_MPC512x_PSC)		+= spi-mpc512x-psc.o

obj-$(CONFIG_SPI_MPC52xx_PSC)		+= spi-mpc52xx-psc.o

obj-$(CONFIG_SPI_MPC52xx)		+= spi-mpc52xx.o

obj-$(CONFIG_SPI_MXS)			+= spi-mxs.o

obj-$(CONFIG_SPI_NUC900)		+= spi-nuc900.o

obj-$(CONFIG_SPI_OC_TINY)		+= spi-oc-tiny.o

obj-$(CONFIG_SPI_OMAP_UWIRE)		+= spi-omap-uwire.o

drivers/spi/spi-mxs.c

0 → 100644
+431 −0
Original line number Diff line number Diff line 
/*

 * Freescale MXS SPI master driver

 *

 * Copyright 2012 DENX Software Engineering, GmbH.

 * Copyright 2012 Freescale Semiconductor, Inc.

 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.

 *

 * Rework and transition to new API by:

 * Marek Vasut <marex@denx.de>

 *

 * Based on previous attempt by:

 * Fabio Estevam <fabio.estevam@freescale.com>

 *

 * Based on code from U-Boot bootloader by:

 * Marek Vasut <marex@denx.de>

 *

 * Based on spi-stmp.c, which is:

 * Author: Dmitry Pervushin <dimka@embeddedalley.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.

 */



#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/ioport.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/of_gpio.h>

#include <linux/platform_device.h>

#include <linux/delay.h>

#include <linux/interrupt.h>

#include <linux/dma-mapping.h>

#include <linux/dmaengine.h>

#include <linux/highmem.h>

#include <linux/clk.h>

#include <linux/err.h>

#include <linux/completion.h>

#include <linux/gpio.h>

#include <linux/regulator/consumer.h>

#include <linux/module.h>

#include <linux/fsl/mxs-dma.h>

#include <linux/pinctrl/consumer.h>

#include <linux/stmp_device.h>

#include <linux/spi/spi.h>

#include <linux/spi/mxs-spi.h>



#define DRIVER_NAME		"mxs-spi"



#define SSP_TIMEOUT		1000	/* 1000 ms */



struct mxs_spi {

	struct mxs_ssp		ssp;

};



static int mxs_spi_setup_transfer(struct spi_device *dev,

				struct spi_transfer *t)

{

	struct mxs_spi *spi = spi_master_get_devdata(dev->master);

	struct mxs_ssp *ssp = &spi->ssp;

	uint8_t bits_per_word;

	uint32_t hz = 0;



	bits_per_word = dev->bits_per_word;

	if (t && t->bits_per_word)

		bits_per_word = t->bits_per_word;



	if (bits_per_word != 8) {

		dev_err(&dev->dev, "%s, unsupported bits_per_word=%d\n",

					__func__, bits_per_word);

		return -EINVAL;

	}



	hz = dev->max_speed_hz;

	if (t && t->speed_hz)

		hz = min(hz, t->speed_hz);

	if (hz == 0) {

		dev_err(&dev->dev, "Cannot continue with zero clock\n");

		return -EINVAL;

	}



	mxs_ssp_set_clk_rate(ssp, hz);



	writel(BF_SSP_CTRL1_SSP_MODE(BV_SSP_CTRL1_SSP_MODE__SPI) |

		     BF_SSP_CTRL1_WORD_LENGTH

		     (BV_SSP_CTRL1_WORD_LENGTH__EIGHT_BITS) |

		     ((dev->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) |

		     ((dev->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0),

		     ssp->base + HW_SSP_CTRL1(ssp));



	writel(0x0, ssp->base + HW_SSP_CMD0);

	writel(0x0, ssp->base + HW_SSP_CMD1);



	return 0;

}



static int mxs_spi_setup(struct spi_device *dev)

{

	int err = 0;



	if (!dev->bits_per_word)

		dev->bits_per_word = 8;



	if (dev->mode & ~(SPI_CPOL | SPI_CPHA))

		return -EINVAL;



	err = mxs_spi_setup_transfer(dev, NULL);

	if (err) {

		dev_err(&dev->dev,

			"Failed to setup transfer, error = %d\n", err);

	}



	return err;

}



static uint32_t mxs_spi_cs_to_reg(unsigned cs)

{

	uint32_t select = 0;



	/*

	 * i.MX28 Datasheet: 17.10.1: HW_SSP_CTRL0

	 *

	 * The bits BM_SSP_CTRL0_WAIT_FOR_CMD and BM_SSP_CTRL0_WAIT_FOR_IRQ

	 * in HW_SSP_CTRL0 register do have multiple usage, please refer to

	 * the datasheet for further details. In SPI mode, they are used to

	 * toggle the chip-select lines (nCS pins).

	 */

	if (cs & 1)

		select |= BM_SSP_CTRL0_WAIT_FOR_CMD;

	if (cs & 2)

		select |= BM_SSP_CTRL0_WAIT_FOR_IRQ;



	return select;

}



static void mxs_spi_set_cs(struct mxs_spi *spi, unsigned cs)

{

	const uint32_t mask =

		BM_SSP_CTRL0_WAIT_FOR_CMD | BM_SSP_CTRL0_WAIT_FOR_IRQ;

	uint32_t select;

	struct mxs_ssp *ssp = &spi->ssp;



	writel(mask, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);

	select = mxs_spi_cs_to_reg(cs);

	writel(select, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);

}



static inline void mxs_spi_enable(struct mxs_spi *spi)

{

	struct mxs_ssp *ssp = &spi->ssp;



	writel(BM_SSP_CTRL0_LOCK_CS,

		ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);

	writel(BM_SSP_CTRL0_IGNORE_CRC,

		ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);

}



static inline void mxs_spi_disable(struct mxs_spi *spi)

{

	struct mxs_ssp *ssp = &spi->ssp;



	writel(BM_SSP_CTRL0_LOCK_CS,

		ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);

	writel(BM_SSP_CTRL0_IGNORE_CRC,

		ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);

}



static int mxs_ssp_wait(struct mxs_spi *spi, int offset, int mask, bool set)

{

	unsigned long timeout = jiffies + msecs_to_jiffies(SSP_TIMEOUT);

	struct mxs_ssp *ssp = &spi->ssp;

	uint32_t reg;



	while (1) {

		reg = readl_relaxed(ssp->base + offset);



		if (set && ((reg & mask) == mask))

			break;



		if (!set && ((~reg & mask) == mask))

			break;



		udelay(1);



		if (time_after(jiffies, timeout))

			return -ETIMEDOUT;

	}

	return 0;

}



static int mxs_spi_txrx_pio(struct mxs_spi *spi, int cs,

			    unsigned char *buf, int len,

			    int *first, int *last, int write)

{

	struct mxs_ssp *ssp = &spi->ssp;



	if (*first)

		mxs_spi_enable(spi);



	mxs_spi_set_cs(spi, cs);



	while (len--) {

		if (*last && len == 0)

			mxs_spi_disable(spi);



		if (ssp->devid == IMX23_SSP) {

			writel(BM_SSP_CTRL0_XFER_COUNT,

				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);

			writel(1,

				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);

		} else {

			writel(1, ssp->base + HW_SSP_XFER_SIZE);

		}



		if (write)

			writel(BM_SSP_CTRL0_READ,

				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);

		else

			writel(BM_SSP_CTRL0_READ,

				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);



		writel(BM_SSP_CTRL0_RUN,

				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);



		if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 1))

			return -ETIMEDOUT;



		if (write)

			writel(*buf, ssp->base + HW_SSP_DATA(ssp));



		writel(BM_SSP_CTRL0_DATA_XFER,

			     ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);



		if (!write) {

			if (mxs_ssp_wait(spi, HW_SSP_STATUS(ssp),

						BM_SSP_STATUS_FIFO_EMPTY, 0))

				return -ETIMEDOUT;



			*buf = (readl(ssp->base + HW_SSP_DATA(ssp)) & 0xff);

		}



		if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 0))

			return -ETIMEDOUT;



		buf++;

	}



	if (len <= 0)

		return 0;



	return -ETIMEDOUT;

}



static int mxs_spi_transfer_one(struct spi_master *master,

				struct spi_message *m)

{

	struct mxs_spi *spi = spi_master_get_devdata(master);

	struct mxs_ssp *ssp = &spi->ssp;

	int first, last;

	struct spi_transfer *t, *tmp_t;

	int status = 0;

	int cs;



	first = last = 0;



	cs = m->spi->chip_select;



	list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) {



		status = mxs_spi_setup_transfer(m->spi, t);

		if (status)

			break;



		if (&t->transfer_list == m->transfers.next)

			first = 1;

		if (&t->transfer_list == m->transfers.prev)

			last = 1;

		if (t->rx_buf && t->tx_buf) {

			dev_err(ssp->dev,

				"Cannot send and receive simultaneously\n");

			status = -EINVAL;

			break;

		}



		if (t->tx_buf)

			status = mxs_spi_txrx_pio(spi, cs, (void *)t->tx_buf,

					     t->len, &first, &last, 1);

		if (t->rx_buf)

			status = mxs_spi_txrx_pio(spi, cs, t->rx_buf,

					     t->len, &first, &last, 0);



		m->actual_length += t->len;

		if (status)

			break;



		first = last = 0;

	}



	m->status = 0;

	spi_finalize_current_message(master);



	return status;

}



static const struct of_device_id mxs_spi_dt_ids[] = {

	{ .compatible = "fsl,imx23-spi", .data = (void *) IMX23_SSP, },

	{ .compatible = "fsl,imx28-spi", .data = (void *) IMX28_SSP, },

	{ /* sentinel */ }

};

MODULE_DEVICE_TABLE(of, mxs_spi_dt_ids);



static int __devinit mxs_spi_probe(struct platform_device *pdev)

{

	const struct of_device_id *of_id =

			of_match_device(mxs_spi_dt_ids, &pdev->dev);

	struct device_node *np = pdev->dev.of_node;

	struct spi_master *master;

	struct mxs_spi *spi;

	struct mxs_ssp *ssp;

	struct resource *iores;

	struct pinctrl *pinctrl;

	struct clk *clk;

	void __iomem *base;

	int devid;

	int ret = 0;



	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!iores)

		return -EINVAL;



	base = devm_request_and_ioremap(&pdev->dev, iores);

	if (!base)

		return -EADDRNOTAVAIL;



	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);

	if (IS_ERR(pinctrl))

		return PTR_ERR(pinctrl);



	clk = devm_clk_get(&pdev->dev, NULL);

	if (IS_ERR(clk))

		return PTR_ERR(clk);



	if (np)

		devid = (enum mxs_ssp_id) of_id->data;

	else

		devid = pdev->id_entry->driver_data;



	master = spi_alloc_master(&pdev->dev, sizeof(*spi));

	if (!master)

		return -ENOMEM;



	master->transfer_one_message = mxs_spi_transfer_one;

	master->setup = mxs_spi_setup;

	master->mode_bits = SPI_CPOL | SPI_CPHA;

	master->num_chipselect = 3;

	master->dev.of_node = np;

	master->flags = SPI_MASTER_HALF_DUPLEX;



	spi = spi_master_get_devdata(master);

	ssp = &spi->ssp;

	ssp->dev = &pdev->dev;

	ssp->clk = clk;

	ssp->base = base;

	ssp->devid = devid;



	clk_prepare_enable(ssp->clk);

	ssp->clk_rate = clk_get_rate(ssp->clk) / 1000;



	stmp_reset_block(ssp->base);



	platform_set_drvdata(pdev, master);



	ret = spi_register_master(master);

	if (ret) {

		dev_err(&pdev->dev, "Cannot register SPI master, %d\n", ret);

		goto out_master_free;

	}



	return 0;



out_master_free:

	platform_set_drvdata(pdev, NULL);

	clk_disable_unprepare(ssp->clk);

	spi_master_put(master);

	return ret;

}



static int __devexit mxs_spi_remove(struct platform_device *pdev)

{

	struct spi_master *master;

	struct mxs_spi *spi;

	struct mxs_ssp *ssp;



	master = platform_get_drvdata(pdev);

	spi = spi_master_get_devdata(master);

	ssp = &spi->ssp;



	spi_unregister_master(master);



	platform_set_drvdata(pdev, NULL);



	clk_disable_unprepare(ssp->clk);



	spi_master_put(master);



	return 0;

}



static struct platform_driver mxs_spi_driver = {

	.probe	= mxs_spi_probe,

	.remove	= __devexit_p(mxs_spi_remove),

	.driver	= {

		.name	= DRIVER_NAME,

		.owner	= THIS_MODULE,

		.of_match_table = mxs_spi_dt_ids,

	},

};



module_platform_driver(mxs_spi_driver);



MODULE_AUTHOR("Marek Vasut <marex@denx.de>");

MODULE_DESCRIPTION("MXS SPI master driver");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:mxs-spi");