i2c: add driver for Freescale i.MX28 (a8da7fec) · Commits · e / devices / android_kernel_sony_msm8994

drivers/i2c/busses/Kconfig

+10 −0

Original line number	Diff line number	Diff line
		@@ -452,6 +452,16 @@ config I2C_MV64XXX
		This driver can also be built as a module. If so, the module
		will be called i2c-mv64xxx.

		config I2C_MXS
		tristate "Freescale i.MX28 I2C interface"
		depends on SOC_IMX28
		help
		Say Y here if you want to use the I2C bus controller on
		the Freescale i.MX28 processors.

		This driver can also be built as a module. If so, the module
		will be called i2c-mxs.

		config I2C_NOMADIK
		tristate "ST-Ericsson Nomadik/Ux500 I2C Controller"
		depends on PLAT_NOMADIK

drivers/i2c/busses/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
		obj-$(CONFIG_I2C_IXP2000) += i2c-ixp2000.o
		obj-$(CONFIG_I2C_MPC) += i2c-mpc.o
		obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
		obj-$(CONFIG_I2C_MXS) += i2c-mxs.o
		obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o
		obj-$(CONFIG_I2C_NUC900) += i2c-nuc900.o
		obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o

drivers/i2c/busses/i2c-mxs.c

0 → 100644

+412 −0

Original line number	Diff line number	Diff line
		/*
		* Freescale MXS I2C bus driver
		*
		* Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
		*
		* based on a (non-working) driver which was:
		*
		* Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
		*
		* TODO: add dma-support if platform-support for it is available
		*
		* 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/slab.h>
		#include <linux/device.h>
		#include <linux/module.h>
		#include <linux/i2c.h>
		#include <linux/err.h>
		#include <linux/interrupt.h>
		#include <linux/completion.h>
		#include <linux/platform_device.h>
		#include <linux/jiffies.h>
		#include <linux/io.h>

		#include <mach/common.h>

		#define DRIVER_NAME "mxs-i2c"

		#define MXS_I2C_CTRL0 (0x00)
		#define MXS_I2C_CTRL0_SET (0x04)

		#define MXS_I2C_CTRL0_SFTRST 0x80000000
		#define MXS_I2C_CTRL0_SEND_NAK_ON_LAST 0x02000000
		#define MXS_I2C_CTRL0_RETAIN_CLOCK 0x00200000
		#define MXS_I2C_CTRL0_POST_SEND_STOP 0x00100000
		#define MXS_I2C_CTRL0_PRE_SEND_START 0x00080000
		#define MXS_I2C_CTRL0_MASTER_MODE 0x00020000
		#define MXS_I2C_CTRL0_DIRECTION 0x00010000
		#define MXS_I2C_CTRL0_XFER_COUNT(v) ((v) & 0x0000FFFF)

		#define MXS_I2C_CTRL1 (0x40)
		#define MXS_I2C_CTRL1_SET (0x44)
		#define MXS_I2C_CTRL1_CLR (0x48)

		#define MXS_I2C_CTRL1_BUS_FREE_IRQ 0x80
		#define MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ 0x40
		#define MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ 0x20
		#define MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ 0x10
		#define MXS_I2C_CTRL1_EARLY_TERM_IRQ 0x08
		#define MXS_I2C_CTRL1_MASTER_LOSS_IRQ 0x04
		#define MXS_I2C_CTRL1_SLAVE_STOP_IRQ 0x02
		#define MXS_I2C_CTRL1_SLAVE_IRQ 0x01

		#define MXS_I2C_IRQ_MASK (MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ \| \
		MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ \| \
		MXS_I2C_CTRL1_EARLY_TERM_IRQ \| \
		MXS_I2C_CTRL1_MASTER_LOSS_IRQ \| \
		MXS_I2C_CTRL1_SLAVE_STOP_IRQ \| \
		MXS_I2C_CTRL1_SLAVE_IRQ)

		#define MXS_I2C_QUEUECTRL (0x60)
		#define MXS_I2C_QUEUECTRL_SET (0x64)
		#define MXS_I2C_QUEUECTRL_CLR (0x68)

		#define MXS_I2C_QUEUECTRL_QUEUE_RUN 0x20
		#define MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE 0x04

		#define MXS_I2C_QUEUESTAT (0x70)
		#define MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY 0x00002000

		#define MXS_I2C_QUEUECMD (0x80)

		#define MXS_I2C_QUEUEDATA (0x90)

		#define MXS_I2C_DATA (0xa0)


		#define MXS_CMD_I2C_SELECT (MXS_I2C_CTRL0_RETAIN_CLOCK \| \
		MXS_I2C_CTRL0_PRE_SEND_START \| \
		MXS_I2C_CTRL0_MASTER_MODE \| \
		MXS_I2C_CTRL0_DIRECTION \| \
		MXS_I2C_CTRL0_XFER_COUNT(1))

		#define MXS_CMD_I2C_WRITE (MXS_I2C_CTRL0_PRE_SEND_START \| \
		MXS_I2C_CTRL0_MASTER_MODE \| \
		MXS_I2C_CTRL0_DIRECTION)

		#define MXS_CMD_I2C_READ (MXS_I2C_CTRL0_SEND_NAK_ON_LAST \| \
		MXS_I2C_CTRL0_MASTER_MODE)

		/**
		* struct mxs_i2c_dev - per device, private MXS-I2C data
		*
		* @dev: driver model device node
		* @regs: IO registers pointer
		* @cmd_complete: completion object for transaction wait
		* @cmd_err: error code for last transaction
		* @adapter: i2c subsystem adapter node
		*/
		struct mxs_i2c_dev {
		struct device *dev;
		void __iomem *regs;
		struct completion cmd_complete;
		u32 cmd_err;
		struct i2c_adapter adapter;
		};

		/*
		* TODO: check if calls to here are really needed. If not, we could get rid of
		* mxs_reset_block and the mach-dependency. Needs an I2C analyzer, probably.
		*/
		static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
		{
		mxs_reset_block(i2c->regs);
		writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
		}

		static void mxs_i2c_pioq_setup_read(struct mxs_i2c_dev *i2c, u8 addr, int len,
		int flags)
		{
		u32 data;

		writel(MXS_CMD_I2C_SELECT, i2c->regs + MXS_I2C_QUEUECMD);

		data = (addr << 1) \| I2C_SMBUS_READ;
		writel(data, i2c->regs + MXS_I2C_DATA);

		data = MXS_CMD_I2C_READ \| MXS_I2C_CTRL0_XFER_COUNT(len) \| flags;
		writel(data, i2c->regs + MXS_I2C_QUEUECMD);
		}

		static void mxs_i2c_pioq_setup_write(struct mxs_i2c_dev *i2c,
		u8 addr, u8 *buf, int len, int flags)
		{
		u32 data;
		int i, shifts_left;

		data = MXS_CMD_I2C_WRITE \| MXS_I2C_CTRL0_XFER_COUNT(len + 1) \| flags;
		writel(data, i2c->regs + MXS_I2C_QUEUECMD);

		/*
		* We have to copy the slave address (u8) and buffer (arbitrary number
		* of u8) into the data register (u32). To achieve that, the u8 are put
		* into the MSBs of 'data' which is then shifted for the next u8. When
		* apropriate, 'data' is written to MXS_I2C_DATA. So, the first u32
		* looks like this:
		*
		* 3 2 1 0
		* 10987654\|32109876\|54321098\|76543210
		* --------+--------+--------+--------
		* buffer+2\|buffer+1\|buffer+0\|slave_addr
		*/

		data = ((addr << 1) \| I2C_SMBUS_WRITE) << 24;

		for (i = 0; i < len; i++) {
		data >>= 8;
		data \|= buf[i] << 24;
		if ((i & 3) == 2)
		writel(data, i2c->regs + MXS_I2C_DATA);
		}

		/* Write out the remaining bytes if any */
		shifts_left = 24 - (i & 3) * 8;
		if (shifts_left)
		writel(data >> shifts_left, i2c->regs + MXS_I2C_DATA);
		}

		/*
		* TODO: should be replaceable with a waitqueue and RD_QUEUE_IRQ (setting the
		* rd_threshold to 1). Couldn't get this to work, though.
		*/
		static int mxs_i2c_wait_for_data(struct mxs_i2c_dev *i2c)
		{
		unsigned long timeout = jiffies + msecs_to_jiffies(1000);

		while (readl(i2c->regs + MXS_I2C_QUEUESTAT)
		& MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY) {
		if (time_after(jiffies, timeout))
		return -ETIMEDOUT;
		cond_resched();
		}

		return 0;
		}

		static int mxs_i2c_finish_read(struct mxs_i2c_dev i2c, u8 buf, int len)
		{
		u32 data;
		int i;

		for (i = 0; i < len; i++) {
		if ((i & 3) == 0) {
		if (mxs_i2c_wait_for_data(i2c))
		return -ETIMEDOUT;
		data = readl(i2c->regs + MXS_I2C_QUEUEDATA);
		}
		buf[i] = data & 0xff;
		data >>= 8;
		}

		return 0;
		}

		/*
		* Low level master read/write transaction.
		*/
		static int mxs_i2c_xfer_msg(struct i2c_adapter adap, struct i2c_msg msg,
		int stop)
		{
		struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
		int ret;
		int flags;

		init_completion(&i2c->cmd_complete);

		dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
		msg->addr, msg->len, msg->flags, stop);

		if (msg->len == 0)
		return -EINVAL;

		flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;

		if (msg->flags & I2C_M_RD)
		mxs_i2c_pioq_setup_read(i2c, msg->addr, msg->len, flags);
		else
		mxs_i2c_pioq_setup_write(i2c, msg->addr, msg->buf, msg->len,
		flags);

		writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
		i2c->regs + MXS_I2C_QUEUECTRL_SET);

		ret = wait_for_completion_timeout(&i2c->cmd_complete,
		msecs_to_jiffies(1000));
		if (ret == 0)
		goto timeout;

		if ((!i2c->cmd_err) && (msg->flags & I2C_M_RD)) {
		ret = mxs_i2c_finish_read(i2c, msg->buf, msg->len);
		if (ret)
		goto timeout;
		}

		if (i2c->cmd_err == -ENXIO)
		mxs_i2c_reset(i2c);

		dev_dbg(i2c->dev, "Done with err=%d\n", i2c->cmd_err);

		return i2c->cmd_err;

		timeout:
		dev_dbg(i2c->dev, "Timeout!\n");
		mxs_i2c_reset(i2c);
		return -ETIMEDOUT;
		}

		static int mxs_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
		int num)
		{
		int i;
		int err;

		for (i = 0; i < num; i++) {
		err = mxs_i2c_xfer_msg(adap, &msgs[i], i == (num - 1));
		if (err)
		return err;
		}

		return num;
		}

		static u32 mxs_i2c_func(struct i2c_adapter *adap)
		{
		return I2C_FUNC_I2C \| (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
		}

		static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
		{
		struct mxs_i2c_dev *i2c = dev_id;
		u32 stat = readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_IRQ_MASK;

		if (!stat)
		return IRQ_NONE;

		if (stat & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
		i2c->cmd_err = -ENXIO;
		else if (stat & (MXS_I2C_CTRL1_EARLY_TERM_IRQ \|
		MXS_I2C_CTRL1_MASTER_LOSS_IRQ \|
		MXS_I2C_CTRL1_SLAVE_STOP_IRQ \| MXS_I2C_CTRL1_SLAVE_IRQ))
		/* MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ is only for slaves */
		i2c->cmd_err = -EIO;
		else
		i2c->cmd_err = 0;

		complete(&i2c->cmd_complete);

		writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
		return IRQ_HANDLED;
		}

		static const struct i2c_algorithm mxs_i2c_algo = {
		.master_xfer = mxs_i2c_xfer,
		.functionality = mxs_i2c_func,
		};

		static int __devinit mxs_i2c_probe(struct platform_device *pdev)
		{
		struct device *dev = &pdev->dev;
		struct mxs_i2c_dev *i2c;
		struct i2c_adapter *adap;
		struct resource *res;
		resource_size_t res_size;
		int err, irq;

		i2c = devm_kzalloc(dev, sizeof(struct mxs_i2c_dev), GFP_KERNEL);
		if (!i2c)
		return -ENOMEM;

		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
		if (!res)
		return -ENOENT;

		res_size = resource_size(res);
		if (!devm_request_mem_region(dev, res->start, res_size, res->name))
		return -EBUSY;

		i2c->regs = devm_ioremap_nocache(dev, res->start, res_size);
		if (!i2c->regs)
		return -EBUSY;

		irq = platform_get_irq(pdev, 0);
		if (irq < 0)
		return irq;

		err = devm_request_irq(dev, irq, mxs_i2c_isr, 0, dev_name(dev), i2c);
		if (err)
		return err;

		i2c->dev = dev;
		platform_set_drvdata(pdev, i2c);

		/* Do reset to enforce correct startup after pinmuxing */
		mxs_i2c_reset(i2c);
		writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
		i2c->regs + MXS_I2C_QUEUECTRL_SET);

		adap = &i2c->adapter;
		strlcpy(adap->name, "MXS I2C adapter", sizeof(adap->name));
		adap->owner = THIS_MODULE;
		adap->algo = &mxs_i2c_algo;
		adap->dev.parent = dev;
		adap->nr = pdev->id;
		i2c_set_adapdata(adap, i2c);
		err = i2c_add_numbered_adapter(adap);
		if (err) {
		dev_err(dev, "Failed to add adapter (%d)\n", err);
		writel(MXS_I2C_CTRL0_SFTRST,
		i2c->regs + MXS_I2C_CTRL0_SET);
		return err;
		}

		return 0;
		}

		static int __devexit mxs_i2c_remove(struct platform_device *pdev)
		{
		struct mxs_i2c_dev *i2c = platform_get_drvdata(pdev);
		int ret;

		ret = i2c_del_adapter(&i2c->adapter);
		if (ret)
		return -EBUSY;

		writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
		i2c->regs + MXS_I2C_QUEUECTRL_CLR);
		writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);

		platform_set_drvdata(pdev, NULL);

		return 0;
		}

		static struct platform_driver mxs_i2c_driver = {
		.driver = {
		.name = DRIVER_NAME,
		.owner = THIS_MODULE,
		},
		.remove = __devexit_p(mxs_i2c_remove),
		};

		static int __init mxs_i2c_init(void)
		{
		return platform_driver_probe(&mxs_i2c_driver, mxs_i2c_probe);
		}
		subsys_initcall(mxs_i2c_init);

		static void __exit mxs_i2c_exit(void)
		{
		platform_driver_unregister(&mxs_i2c_driver);
		}
		module_exit(mxs_i2c_exit);

		MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
		MODULE_DESCRIPTION("MXS I2C Bus Driver");
		MODULE_LICENSE("GPL");
		MODULE_ALIAS("platform:" DRIVER_NAME);