spi: add SPI driver for most known i.MX SoCs

This driver has been tested on i.MX1/i.MX27/i.MX35 with an AT25 type
EEPROM and on i.MX27/i.MX31 with a Freescale MC13783 PMIC.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: David Brownell <david-b@pacbell.net>
Cc: Andrea Paterniani <a.paterniani@swapp-eng.it>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 721 insertions, 0 deletions

diff --git a/arch/arm/plat-mxc/include/mach/spi.h b/arch/arm/plat-mxc/include/mach/spi.h
new file mode 100644
index 000000000000..08be445e8eb8
--- /dev/null
+++ b/arch/arm/plat-mxc/include/mach/spi.h
@@ -0,0 +1,27 @@
+
+#ifndef __MACH_SPI_H_
+#define __MACH_SPI_H_
+
+/*
+ * struct spi_imx_master - device.platform_data for SPI controller devices.
+ * @chipselect: Array of chipselects for this master. Numbers >= 0 mean gpio
+ *              pins, numbers < 0 mean internal CSPI chipselects according
+ *              to MXC_SPI_CS(). Normally you want to use gpio based chip
+ *              selects as the CSPI module tries to be intelligent about
+ *              when to assert the chipselect: The CSPI module deasserts the
+ *              chipselect once it runs out of input data. The other problem
+ *              is that it is not possible to mix between high active and low
+ *              active chipselects on one single bus using the internal
+ *              chipselects. Unfortunately Freescale decided to put some
+ *              chipselects on dedicated pins which are not usable as gpios,
+ *              so we have to support the internal chipselects.
+ * @num_chipselect: ARRAY_SIZE(chipselect)
+ */
+struct spi_imx_master {
+        int     *chipselect;
+        int     num_chipselect;
+};
+
+#define MXC_SPI_CS(no)  ((no) - 32)
+
+#endif /* __MACH_SPI_H_*/
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 927a8b77e604..cd3acfe9d136 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -116,6 +116,14 @@ config SPI_GPIO
           GPIO operations, you should be able to leverage that for better
           speed with a custom version of this driver; see the source code.
 
+config SPI_IMX
+        tristate "Freescale i.MX SPI controllers"
+        depends on ARCH_MXC
+        select SPI_BITBANG
+        help
+          This enables using the Freescale i.MX SPI controllers in master
+          mode.
+
 config SPI_LM70_LLP
         tristate "Parallel port adapter for LM70 eval board (DEVELOPMENT)"
         depends on PARPORT && EXPERIMENTAL
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index bdd1f3a1e542..fbfc5f22f4fa 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_SPI_BITBANG)		+= spi_bitbang.o
 obj-$(CONFIG_SPI_AU1550)                += au1550_spi.o
 obj-$(CONFIG_SPI_BUTTERFLY)             += spi_butterfly.o
 obj-$(CONFIG_SPI_GPIO)                  += spi_gpio.o
+obj-$(CONFIG_SPI_IMX)                   += mxc_spi.o
 obj-$(CONFIG_SPI_LM70_LLP)              += spi_lm70llp.o
 obj-$(CONFIG_SPI_PXA2XX)                += pxa2xx_spi.o
 obj-$(CONFIG_SPI_OMAP_UWIRE)            += omap_uwire.o
diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
new file mode 100644
index 000000000000..b1447236ae81
--- /dev/null
+++ b/drivers/spi/mxc_spi.c
@@ -0,0 +1,685 @@
+/*
+ * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright (C) 2008 Juergen Beisert
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301, USA.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/types.h>
+
+#include <mach/spi.h>
+
+#define DRIVER_NAME "spi_imx"
+
+#define MXC_CSPIRXDATA          0x00
+#define MXC_CSPITXDATA          0x04
+#define MXC_CSPICTRL            0x08
+#define MXC_CSPIINT             0x0c
+#define MXC_RESET               0x1c
+
+/* generic defines to abstract from the different register layouts */
+#define MXC_INT_RR      (1 << 0) /* Receive data ready interrupt */
+#define MXC_INT_TE      (1 << 1) /* Transmit FIFO empty interrupt */
+
+struct mxc_spi_config {
+        unsigned int speed_hz;
+        unsigned int bpw;
+        unsigned int mode;
+        int cs;
+};
+
+struct mxc_spi_data {
+        struct spi_bitbang bitbang;
+
+        struct completion xfer_done;
+        void *base;
+        int irq;
+        struct clk *clk;
+        unsigned long spi_clk;
+        int *chipselect;
+
+        unsigned int count;
+        void (*tx)(struct mxc_spi_data *);
+        void (*rx)(struct mxc_spi_data *);
+        void *rx_buf;
+        const void *tx_buf;
+        unsigned int txfifo; /* number of words pushed in tx FIFO */
+
+        /* SoC specific functions */
+        void (*intctrl)(struct mxc_spi_data *, int);
+        int (*config)(struct mxc_spi_data *, struct mxc_spi_config *);
+        void (*trigger)(struct mxc_spi_data *);
+        int (*rx_available)(struct mxc_spi_data *);
+};
+
+#define MXC_SPI_BUF_RX(type)                                            \
+static void mxc_spi_buf_rx_##type(struct mxc_spi_data *mxc_spi)         \
+{                                                                       \
+        unsigned int val = readl(mxc_spi->base + MXC_CSPIRXDATA);       \
+                                                                        \
+        if (mxc_spi->rx_buf) {                                          \
+                *(type *)mxc_spi->rx_buf = val;                         \
+                mxc_spi->rx_buf += sizeof(type);                        \
+        }                                                               \
+}
+
+#define MXC_SPI_BUF_TX(type)                                            \
+static void mxc_spi_buf_tx_##type(struct mxc_spi_data *mxc_spi)         \
+{                                                                       \
+        type val = 0;                                                   \
+                                                                        \
+        if (mxc_spi->tx_buf) {                                          \
+                val = *(type *)mxc_spi->tx_buf;                         \
+                mxc_spi->tx_buf += sizeof(type);                        \
+        }                                                               \
+                                                                        \
+        mxc_spi->count -= sizeof(type);                                 \
+                                                                        \
+        writel(val, mxc_spi->base + MXC_CSPITXDATA);                    \
+}
+
+MXC_SPI_BUF_RX(u8)
+MXC_SPI_BUF_TX(u8)
+MXC_SPI_BUF_RX(u16)
+MXC_SPI_BUF_TX(u16)
+MXC_SPI_BUF_RX(u32)
+MXC_SPI_BUF_TX(u32)
+
+/* First entry is reserved, second entry is valid only if SDHC_SPIEN is set
+ * (which is currently not the case in this driver)
+ */
+static int mxc_clkdivs[] = {0, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96, 128, 192,
+        256, 384, 512, 768, 1024};
+
+/* MX21, MX27 */
+static unsigned int mxc_spi_clkdiv_1(unsigned int fin,
+                unsigned int fspi)
+{
+        int i, max;
+
+        if (cpu_is_mx21())
+                max = 18;
+        else
+                max = 16;
+
+        for (i = 2; i < max; i++)
+                if (fspi * mxc_clkdivs[i] >= fin)
+                        return i;
+
+        return max;
+}
+
+/* MX1, MX31, MX35 */
+static unsigned int mxc_spi_clkdiv_2(unsigned int fin,
+                unsigned int fspi)
+{
+        int i, div = 4;
+
+        for (i = 0; i < 7; i++) {
+                if (fspi * div >= fin)
+                        return i;
+                div <<= 1;
+        }
+
+        return 7;
+}
+
+#define MX31_INTREG_TEEN        (1 << 0)
+#define MX31_INTREG_RREN        (1 << 3)
+
+#define MX31_CSPICTRL_ENABLE    (1 << 0)
+#define MX31_CSPICTRL_MASTER    (1 << 1)
+#define MX31_CSPICTRL_XCH       (1 << 2)
+#define MX31_CSPICTRL_POL       (1 << 4)
+#define MX31_CSPICTRL_PHA       (1 << 5)
+#define MX31_CSPICTRL_SSCTL     (1 << 6)
+#define MX31_CSPICTRL_SSPOL     (1 << 7)
+#define MX31_CSPICTRL_BC_SHIFT  8
+#define MX35_CSPICTRL_BL_SHIFT  20
+#define MX31_CSPICTRL_CS_SHIFT  24
+#define MX35_CSPICTRL_CS_SHIFT  12
+#define MX31_CSPICTRL_DR_SHIFT  16
+
+#define MX31_CSPISTATUS         0x14
+#define MX31_STATUS_RR          (1 << 3)
+
+/* These functions also work for the i.MX35, but be aware that
+ * the i.MX35 has a slightly different register layout for bits
+ * we do not use here.
+ */
+static void mx31_intctrl(struct mxc_spi_data *mxc_spi, int enable)
+{
+        unsigned int val = 0;
+
+        if (enable & MXC_INT_TE)
+                val |= MX31_INTREG_TEEN;
+        if (enable & MXC_INT_RR)
+                val |= MX31_INTREG_RREN;
+
+        writel(val, mxc_spi->base + MXC_CSPIINT);
+}
+
+static void mx31_trigger(struct mxc_spi_data *mxc_spi)
+{
+        unsigned int reg;
+
+        reg = readl(mxc_spi->base + MXC_CSPICTRL);
+        reg |= MX31_CSPICTRL_XCH;
+        writel(reg, mxc_spi->base + MXC_CSPICTRL);
+}
+
+static int mx31_config(struct mxc_spi_data *mxc_spi,
+                struct mxc_spi_config *config)
+{
+        unsigned int reg = MX31_CSPICTRL_ENABLE | MX31_CSPICTRL_MASTER;
+
+        reg |= mxc_spi_clkdiv_2(mxc_spi->spi_clk, config->speed_hz) <<
+                MX31_CSPICTRL_DR_SHIFT;
+
+        if (cpu_is_mx31())
+                reg |= (config->bpw - 1) << MX31_CSPICTRL_BC_SHIFT;
+        else if (cpu_is_mx35()) {
+                reg |= (config->bpw - 1) << MX35_CSPICTRL_BL_SHIFT;
+                reg |= MX31_CSPICTRL_SSCTL;
+        }
+
+        if (config->mode & SPI_CPHA)
+                reg |= MX31_CSPICTRL_PHA;
+        if (config->mode & SPI_CPOL)
+                reg |= MX31_CSPICTRL_POL;
+        if (config->mode & SPI_CS_HIGH)
+                reg |= MX31_CSPICTRL_SSPOL;
+        if (config->cs < 0) {
+                if (cpu_is_mx31())
+                        reg |= (config->cs + 32) << MX31_CSPICTRL_CS_SHIFT;
+                else if (cpu_is_mx35())
+                        reg |= (config->cs + 32) << MX35_CSPICTRL_CS_SHIFT;
+        }
+
+        writel(reg, mxc_spi->base + MXC_CSPICTRL);
+
+        return 0;
+}
+
+static int mx31_rx_available(struct mxc_spi_data *mxc_spi)
+{
+        return readl(mxc_spi->base + MX31_CSPISTATUS) & MX31_STATUS_RR;
+}
+
+#define MX27_INTREG_RR          (1 << 4)
+#define MX27_INTREG_TEEN        (1 << 9)
+#define MX27_INTREG_RREN        (1 << 13)
+
+#define MX27_CSPICTRL_POL       (1 << 5)
+#define MX27_CSPICTRL_PHA       (1 << 6)
+#define MX27_CSPICTRL_SSPOL     (1 << 8)
+#define MX27_CSPICTRL_XCH       (1 << 9)
+#define MX27_CSPICTRL_ENABLE    (1 << 10)
+#define MX27_CSPICTRL_MASTER    (1 << 11)
+#define MX27_CSPICTRL_DR_SHIFT  14
+#define MX27_CSPICTRL_CS_SHIFT  19
+
+static void mx27_intctrl(struct mxc_spi_data *mxc_spi, int enable)
+{
+        unsigned int val = 0;
+
+        if (enable & MXC_INT_TE)
+                val |= MX27_INTREG_TEEN;
+        if (enable & MXC_INT_RR)
+                val |= MX27_INTREG_RREN;
+
+        writel(val, mxc_spi->base + MXC_CSPIINT);
+}
+
+static void mx27_trigger(struct mxc_spi_data *mxc_spi)
+{
+        unsigned int reg;
+
+        reg = readl(mxc_spi->base + MXC_CSPICTRL);
+        reg |= MX27_CSPICTRL_XCH;
+        writel(reg, mxc_spi->base + MXC_CSPICTRL);
+}
+
+static int mx27_config(struct mxc_spi_data *mxc_spi,
+                struct mxc_spi_config *config)
+{
+        unsigned int reg = MX27_CSPICTRL_ENABLE | MX27_CSPICTRL_MASTER;
+
+        reg |= mxc_spi_clkdiv_1(mxc_spi->spi_clk, config->speed_hz) <<
+                MX27_CSPICTRL_DR_SHIFT;
+        reg |= config->bpw - 1;
+
+        if (config->mode & SPI_CPHA)
+                reg |= MX27_CSPICTRL_PHA;
+        if (config->mode & SPI_CPOL)
+                reg |= MX27_CSPICTRL_POL;
+        if (config->mode & SPI_CS_HIGH)
+                reg |= MX27_CSPICTRL_SSPOL;
+        if (config->cs < 0)
+                reg |= (config->cs + 32) << MX27_CSPICTRL_CS_SHIFT;
+
+        writel(reg, mxc_spi->base + MXC_CSPICTRL);
+
+        return 0;
+}
+
+static int mx27_rx_available(struct mxc_spi_data *mxc_spi)
+{
+        return readl(mxc_spi->base + MXC_CSPIINT) & MX27_INTREG_RR;
+}
+
+#define MX1_INTREG_RR           (1 << 3)
+#define MX1_INTREG_TEEN         (1 << 8)
+#define MX1_INTREG_RREN         (1 << 11)
+
+#define MX1_CSPICTRL_POL        (1 << 4)
+#define MX1_CSPICTRL_PHA        (1 << 5)
+#define MX1_CSPICTRL_XCH        (1 << 8)
+#define MX1_CSPICTRL_ENABLE     (1 << 9)
+#define MX1_CSPICTRL_MASTER     (1 << 10)
+#define MX1_CSPICTRL_DR_SHIFT   13
+
+static void mx1_intctrl(struct mxc_spi_data *mxc_spi, int enable)
+{
+        unsigned int val = 0;
+
+        if (enable & MXC_INT_TE)
+                val |= MX1_INTREG_TEEN;
+        if (enable & MXC_INT_RR)
+                val |= MX1_INTREG_RREN;
+
+        writel(val, mxc_spi->base + MXC_CSPIINT);
+}
+
+static void mx1_trigger(struct mxc_spi_data *mxc_spi)
+{
+        unsigned int reg;
+
+        reg = readl(mxc_spi->base + MXC_CSPICTRL);
+        reg |= MX1_CSPICTRL_XCH;
+        writel(reg, mxc_spi->base + MXC_CSPICTRL);
+}
+
+static int mx1_config(struct mxc_spi_data *mxc_spi,
+                struct mxc_spi_config *config)
+{
+        unsigned int reg = MX1_CSPICTRL_ENABLE | MX1_CSPICTRL_MASTER;
+
+        reg |= mxc_spi_clkdiv_2(mxc_spi->spi_clk, config->speed_hz) <<
+                MX1_CSPICTRL_DR_SHIFT;
+        reg |= config->bpw - 1;
+
+        if (config->mode & SPI_CPHA)
+                reg |= MX1_CSPICTRL_PHA;
+        if (config->mode & SPI_CPOL)
+                reg |= MX1_CSPICTRL_POL;
+
+        writel(reg, mxc_spi->base + MXC_CSPICTRL);
+
+        return 0;
+}
+
+static int mx1_rx_available(struct mxc_spi_data *mxc_spi)
+{
+        return readl(mxc_spi->base + MXC_CSPIINT) & MX1_INTREG_RR;
+}
+
+static void mxc_spi_chipselect(struct spi_device *spi, int is_active)
+{
+        struct mxc_spi_data *mxc_spi = spi_master_get_devdata(spi->master);
+        unsigned int cs = 0;
+        int gpio = mxc_spi->chipselect[spi->chip_select];
+        struct mxc_spi_config config;
+
+        if (spi->mode & SPI_CS_HIGH)
+                cs = 1;
+
+        if (is_active == BITBANG_CS_INACTIVE) {
+                if (gpio >= 0)
+                        gpio_set_value(gpio, !cs);
+                return;
+        }
+
+        config.bpw = spi->bits_per_word;
+        config.speed_hz = spi->max_speed_hz;
+        config.mode = spi->mode;
+        config.cs = mxc_spi->chipselect[spi->chip_select];
+
+        mxc_spi->config(mxc_spi, &config);
+
+        /* Initialize the functions for transfer */
+        if (config.bpw <= 8) {
+                mxc_spi->rx = mxc_spi_buf_rx_u8;
+                mxc_spi->tx = mxc_spi_buf_tx_u8;
+        } else if (config.bpw <= 16) {
+                mxc_spi->rx = mxc_spi_buf_rx_u16;
+                mxc_spi->tx = mxc_spi_buf_tx_u16;
+        } else if (config.bpw <= 32) {
+                mxc_spi->rx = mxc_spi_buf_rx_u32;
+                mxc_spi->tx = mxc_spi_buf_tx_u32;
+        } else
+                BUG();
+
+        if (gpio >= 0)
+                gpio_set_value(gpio, cs);
+
+        return;
+}
+
+static void mxc_spi_push(struct mxc_spi_data *mxc_spi)
+{
+        while (mxc_spi->txfifo < 8) {
+                if (!mxc_spi->count)
+                        break;
+                mxc_spi->tx(mxc_spi);
+                mxc_spi->txfifo++;
+        }
+
+        mxc_spi->trigger(mxc_spi);
+}
+
+static irqreturn_t mxc_spi_isr(int irq, void *dev_id)
+{
+        struct mxc_spi_data *mxc_spi = dev_id;
+
+        while (mxc_spi->rx_available(mxc_spi)) {
+                mxc_spi->rx(mxc_spi);
+                mxc_spi->txfifo--;
+        }
+
+        if (mxc_spi->count) {
+                mxc_spi_push(mxc_spi);
+                return IRQ_HANDLED;
+        }
+
+        if (mxc_spi->txfifo) {
+                /* No data left to push, but still waiting for rx data,
+                 * enable receive data available interrupt.
+                 */
+                mxc_spi->intctrl(mxc_spi, MXC_INT_RR);
+                return IRQ_HANDLED;
+        }
+
+        mxc_spi->intctrl(mxc_spi, 0);
+        complete(&mxc_spi->xfer_done);
+
+        return IRQ_HANDLED;
+}
+
+static int mxc_spi_setupxfer(struct spi_device *spi,
+                                 struct spi_transfer *t)
+{
+        struct mxc_spi_data *mxc_spi = spi_master_get_devdata(spi->master);
+        struct mxc_spi_config config;
+
+        config.bpw = t ? t->bits_per_word : spi->bits_per_word;
+        config.speed_hz  = t ? t->speed_hz : spi->max_speed_hz;
+        config.mode = spi->mode;
+
+        mxc_spi->config(mxc_spi, &config);
+
+        return 0;
+}
+
+static int mxc_spi_transfer(struct spi_device *spi,
+                                struct spi_transfer *transfer)
+{
+        struct mxc_spi_data *mxc_spi = spi_master_get_devdata(spi->master);
+
+        mxc_spi->tx_buf = transfer->tx_buf;
+        mxc_spi->rx_buf = transfer->rx_buf;
+        mxc_spi->count = transfer->len;
+        mxc_spi->txfifo = 0;
+
+        init_completion(&mxc_spi->xfer_done);
+
+        mxc_spi_push(mxc_spi);
+
+        mxc_spi->intctrl(mxc_spi, MXC_INT_TE);
+
+        wait_for_completion(&mxc_spi->xfer_done);
+
+        return transfer->len;
+}
+
+static int mxc_spi_setup(struct spi_device *spi)
+{
+        if (!spi->bits_per_word)
+                spi->bits_per_word = 8;
+
+        pr_debug("%s: mode %d, %u bpw, %d hz\n", __func__,
+                 spi->mode, spi->bits_per_word, spi->max_speed_hz);
+
+        mxc_spi_chipselect(spi, BITBANG_CS_INACTIVE);
+
+        return 0;
+}
+
+static void mxc_spi_cleanup(struct spi_device *spi)
+{
+}
+
+static int __init mxc_spi_probe(struct platform_device *pdev)
+{
+        struct spi_imx_master *mxc_platform_info;
+        struct spi_master *master;
+        struct mxc_spi_data *mxc_spi;
+        struct resource *res;
+        int i, ret;
+
+        mxc_platform_info = (struct spi_imx_master *)pdev->dev.platform_data;
+        if (!mxc_platform_info) {
+                dev_err(&pdev->dev, "can't get the platform data\n");
+                return -EINVAL;
+        }
+
+        master = spi_alloc_master(&pdev->dev, sizeof(struct mxc_spi_data));
+        if (!master)
+                return -ENOMEM;
+
+        platform_set_drvdata(pdev, master);
+
+        master->bus_num = pdev->id;
+        master->num_chipselect = mxc_platform_info->num_chipselect;
+
+        mxc_spi = spi_master_get_devdata(master);
+        mxc_spi->bitbang.master = spi_master_get(master);
+        mxc_spi->chipselect = mxc_platform_info->chipselect;
+
+        for (i = 0; i < master->num_chipselect; i++) {
+                if (mxc_spi->chipselect[i] < 0)
+                        continue;
+                ret = gpio_request(mxc_spi->chipselect[i], DRIVER_NAME);
+                if (ret) {
+                        i--;
+                        while (i > 0)
+                                if (mxc_spi->chipselect[i] >= 0)
+                                        gpio_free(mxc_spi->chipselect[i--]);
+                        dev_err(&pdev->dev, "can't get cs gpios");
+                        goto out_master_put;
+                }
+                gpio_direction_output(mxc_spi->chipselect[i], 1);
+        }
+
+        mxc_spi->bitbang.chipselect = mxc_spi_chipselect;
+        mxc_spi->bitbang.setup_transfer = mxc_spi_setupxfer;
+        mxc_spi->bitbang.txrx_bufs = mxc_spi_transfer;
+        mxc_spi->bitbang.master->setup = mxc_spi_setup;
+        mxc_spi->bitbang.master->cleanup = mxc_spi_cleanup;
+
+        init_completion(&mxc_spi->xfer_done);
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res) {
+                dev_err(&pdev->dev, "can't get platform resource\n");
+                ret = -ENOMEM;
+                goto out_gpio_free;
+        }
+
+        if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
+                dev_err(&pdev->dev, "request_mem_region failed\n");
+                ret = -EBUSY;
+                goto out_gpio_free;
+        }
+
+        mxc_spi->base = ioremap(res->start, resource_size(res));
+        if (!mxc_spi->base) {
+                ret = -EINVAL;
+                goto out_release_mem;
+        }
+
+        mxc_spi->irq = platform_get_irq(pdev, 0);
+        if (!mxc_spi->irq) {
+                ret = -EINVAL;
+                goto out_iounmap;
+        }
+
+        ret = request_irq(mxc_spi->irq, mxc_spi_isr, 0, DRIVER_NAME, mxc_spi);
+        if (ret) {
+                dev_err(&pdev->dev, "can't get irq%d: %d\n", mxc_spi->irq, ret);
+                goto out_iounmap;
+        }
+
+        if (cpu_is_mx31() || cpu_is_mx35()) {
+                mxc_spi->intctrl = mx31_intctrl;
+                mxc_spi->config = mx31_config;
+                mxc_spi->trigger = mx31_trigger;
+                mxc_spi->rx_available = mx31_rx_available;
+        } else  if (cpu_is_mx27() || cpu_is_mx21()) {
+                mxc_spi->intctrl = mx27_intctrl;
+                mxc_spi->config = mx27_config;
+                mxc_spi->trigger = mx27_trigger;
+                mxc_spi->rx_available = mx27_rx_available;
+        } else if (cpu_is_mx1()) {
+                mxc_spi->intctrl = mx1_intctrl;
+                mxc_spi->config = mx1_config;
+                mxc_spi->trigger = mx1_trigger;
+                mxc_spi->rx_available = mx1_rx_available;
+        } else
+                BUG();
+
+        mxc_spi->clk = clk_get(&pdev->dev, NULL);
+        if (IS_ERR(mxc_spi->clk)) {
+                dev_err(&pdev->dev, "unable to get clock\n");
+                ret = PTR_ERR(mxc_spi->clk);
+                goto out_free_irq;
+        }
+
+        clk_enable(mxc_spi->clk);
+        mxc_spi->spi_clk = clk_get_rate(mxc_spi->clk);
+
+        if (!cpu_is_mx31() || !cpu_is_mx35())
+                writel(1, mxc_spi->base + MXC_RESET);
+
+        mxc_spi->intctrl(mxc_spi, 0);
+
+        ret = spi_bitbang_start(&mxc_spi->bitbang);
+        if (ret) {
+                dev_err(&pdev->dev, "bitbang start failed with %d\n", ret);
+                goto out_clk_put;
+        }
+
+        dev_info(&pdev->dev, "probed\n");
+
+        return ret;
+
+out_clk_put:
+        clk_disable(mxc_spi->clk);
+        clk_put(mxc_spi->clk);
+out_free_irq:
+        free_irq(mxc_spi->irq, mxc_spi);
+out_iounmap:
+        iounmap(mxc_spi->base);
+out_release_mem:
+        release_mem_region(res->start, resource_size(res));
+out_gpio_free:
+        for (i = 0; i < master->num_chipselect; i++)
+                if (mxc_spi->chipselect[i] >= 0)
+                        gpio_free(mxc_spi->chipselect[i]);
+out_master_put:
+        spi_master_put(master);
+        kfree(master);
+        platform_set_drvdata(pdev, NULL);
+        return ret;
+}
+
+static int __exit mxc_spi_remove(struct platform_device *pdev)
+{
+        struct spi_master *master = platform_get_drvdata(pdev);
+        struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        struct mxc_spi_data *mxc_spi = spi_master_get_devdata(master);
+        int i;
+
+        spi_bitbang_stop(&mxc_spi->bitbang);
+
+        writel(0, mxc_spi->base + MXC_CSPICTRL);
+        clk_disable(mxc_spi->clk);
+        clk_put(mxc_spi->clk);
+        free_irq(mxc_spi->irq, mxc_spi);
+        iounmap(mxc_spi->base);
+
+        for (i = 0; i < master->num_chipselect; i++)
+                if (mxc_spi->chipselect[i] >= 0)
+                        gpio_free(mxc_spi->chipselect[i]);
+
+        spi_master_put(master);
+
+        release_mem_region(res->start, resource_size(res));
+
+        platform_set_drvdata(pdev, NULL);
+
+        return 0;
+}
+
+static struct platform_driver mxc_spi_driver = {
+        .driver = {
+                   .name = DRIVER_NAME,
+                   .owner = THIS_MODULE,
+                   },
+        .probe = mxc_spi_probe,
+        .remove = __exit_p(mxc_spi_remove),
+};
+
+static int __init mxc_spi_init(void)
+{
+        return platform_driver_register(&mxc_spi_driver);
+}
+
+static void __exit mxc_spi_exit(void)
+{
+        platform_driver_unregister(&mxc_spi_driver);
+}
+
+module_init(mxc_spi_init);
+module_exit(mxc_spi_exit);
+
+MODULE_DESCRIPTION("SPI Master Controller driver");
+MODULE_AUTHOR("Sascha Hauer, Pengutronix");
+MODULE_LICENSE("GPL");