spi: add SPI driver for most known i.MX SoCs (b5f3294f) · Commits · e / devices / android_kernel_sony_msm8994

arch/arm/plat-mxc/include/mach/spi.h

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		#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_*/

drivers/spi/Kconfig

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		@@ -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

drivers/spi/Makefile

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		@@ -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

drivers/spi/mxc_spi.c

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		/*
		* 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");