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: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Chris Ball <cjb@laptop.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

3 files changed, 439 insertions, 0 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 5f84b5563c2d..6992b30b4e42 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -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)
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 3920dcf4c740..3b72d87b3309 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -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
diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c
new file mode 100644
index 000000000000..7bf826f5af59
--- /dev/null
+++ b/drivers/spi/spi-mxs.c
@@ -0,0 +1,431 @@
+/*
+ * 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");