[mirror_ubuntu-zesty-kernel.git] / drivers / i2c / busses / i2c-davinci.c

/*
 * TI DAVINCI I2C adapter driver.
 *
 * Copyright (C) 2006 Texas Instruments.
 * Copyright (C) 2007 MontaVista Software Inc.
 *
 * Updated by Vinod & Sudhakar Feb 2005
 *
 * ----------------------------------------------------------------------------
 *
 * 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, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 * ----------------------------------------------------------------------------
 *
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>

#include <asm/hardware.h>
#include <asm/mach-types.h>

#include <asm/arch/i2c.h>

/* ----- global defines ----------------------------------------------- */

#define DAVINCI_I2C_TIMEOUT	(1*HZ)
#define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_AAS | \
				 DAVINCI_I2C_IMR_SCD | \
				 DAVINCI_I2C_IMR_ARDY | \
				 DAVINCI_I2C_IMR_NACK | \
				 DAVINCI_I2C_IMR_AL)

#define DAVINCI_I2C_OAR_REG	0x00
#define DAVINCI_I2C_IMR_REG	0x04
#define DAVINCI_I2C_STR_REG	0x08
#define DAVINCI_I2C_CLKL_REG	0x0c
#define DAVINCI_I2C_CLKH_REG	0x10
#define DAVINCI_I2C_CNT_REG	0x14
#define DAVINCI_I2C_DRR_REG	0x18
#define DAVINCI_I2C_SAR_REG	0x1c
#define DAVINCI_I2C_DXR_REG	0x20
#define DAVINCI_I2C_MDR_REG	0x24
#define DAVINCI_I2C_IVR_REG	0x28
#define DAVINCI_I2C_EMDR_REG	0x2c
#define DAVINCI_I2C_PSC_REG	0x30

#define DAVINCI_I2C_IVR_AAS	0x07
#define DAVINCI_I2C_IVR_SCD	0x06
#define DAVINCI_I2C_IVR_XRDY	0x05
#define DAVINCI_I2C_IVR_RDR	0x04
#define DAVINCI_I2C_IVR_ARDY	0x03
#define DAVINCI_I2C_IVR_NACK	0x02
#define DAVINCI_I2C_IVR_AL	0x01

#define DAVINCI_I2C_STR_BB	(1 << 12)
#define DAVINCI_I2C_STR_RSFULL	(1 << 11)
#define DAVINCI_I2C_STR_SCD	(1 << 5)
#define DAVINCI_I2C_STR_ARDY	(1 << 2)
#define DAVINCI_I2C_STR_NACK	(1 << 1)
#define DAVINCI_I2C_STR_AL	(1 << 0)

#define DAVINCI_I2C_MDR_NACK	(1 << 15)
#define DAVINCI_I2C_MDR_STT	(1 << 13)
#define DAVINCI_I2C_MDR_STP	(1 << 11)
#define DAVINCI_I2C_MDR_MST	(1 << 10)
#define DAVINCI_I2C_MDR_TRX	(1 << 9)
#define DAVINCI_I2C_MDR_XA	(1 << 8)
#define DAVINCI_I2C_MDR_IRS	(1 << 5)

#define DAVINCI_I2C_IMR_AAS	(1 << 6)
#define DAVINCI_I2C_IMR_SCD	(1 << 5)
#define DAVINCI_I2C_IMR_XRDY	(1 << 4)
#define DAVINCI_I2C_IMR_RRDY	(1 << 3)
#define DAVINCI_I2C_IMR_ARDY	(1 << 2)
#define DAVINCI_I2C_IMR_NACK	(1 << 1)
#define DAVINCI_I2C_IMR_AL	(1 << 0)

#define MOD_REG_BIT(val, mask, set) do { \
	if (set) { \
		val |= mask; \
	} else { \
		val &= ~mask; \
	} \
} while (0)

struct davinci_i2c_dev {
	struct device           *dev;
	void __iomem		*base;
	struct completion	cmd_complete;
	struct clk              *clk;
	int			cmd_err;
	u8			*buf;
	size_t			buf_len;
	int			irq;
	struct i2c_adapter	adapter;
};

/* default platform data to use if not supplied in the platform_device */
static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
	.bus_freq	= 100,
	.bus_delay	= 0,
};

static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
					 int reg, u16 val)
{
	__raw_writew(val, i2c_dev->base + reg);
}

static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
{
	return __raw_readw(i2c_dev->base + reg);
}

/*
 * This functions configures I2C and brings I2C out of reset.
 * This function is called during I2C init function. This function
 * also gets called if I2C encounters any errors.
 */
static int i2c_davinci_init(struct davinci_i2c_dev *dev)
{
	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
	u16 psc;
	u32 clk;
	u32 d;
	u32 clkh;
	u32 clkl;
	u32 input_clock = clk_get_rate(dev->clk);
	u16 w;

	if (!pdata)
		pdata = &davinci_i2c_platform_data_default;

	/* put I2C into reset */
	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
	MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);

	/* NOTE: I2C Clock divider programming info
	 * As per I2C specs the following formulas provide prescaler
	 * and low/high divider values
	 * input clk --> PSC Div -----------> ICCL/H Div --> output clock
	 *                       module clk
	 *
	 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
	 *
	 * Thus,
	 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
	 *
	 * where if PSC == 0, d = 7,
	 *       if PSC == 1, d = 6
	 *       if PSC > 1 , d = 5
	 */

	/* get minimum of 7 MHz clock, but max of 12 MHz */
	psc = (input_clock / 7000000) - 1;
	if ((input_clock / (psc + 1)) > 12000000)
		psc++;	/* better to run under spec than over */
	d = (psc >= 2) ? 5 : 7 - psc;

	clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
	clkh = clk >> 1;
	clkl = clk - clkh;

	davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);

	dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
	dev_dbg(dev->dev, "PSC  = %d\n",
		davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
	dev_dbg(dev->dev, "CLKL = %d\n",
		davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
	dev_dbg(dev->dev, "CLKH = %d\n",
		davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
	dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
		pdata->bus_freq, pdata->bus_delay);

	/* Take the I2C module out of reset: */
	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
	MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);

	/* Enable interrupts */
	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);

	return 0;
}

/*
 * Waiting for bus not busy
 */
static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
					 char allow_sleep)
{
	unsigned long timeout;

	timeout = jiffies + DAVINCI_I2C_TIMEOUT;
	while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
	       & DAVINCI_I2C_STR_BB) {
		if (time_after(jiffies, timeout)) {
			dev_warn(dev->dev,
				 "timeout waiting for bus ready\n");
			return -ETIMEDOUT;
		}
		if (allow_sleep)
			schedule_timeout(1);
	}

	return 0;
}

/*
 * Low level master read/write transaction. This function is called
 * from i2c_davinci_xfer.
 */
static int
i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
{
	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
	u32 flag;
	u32 stat;
	u16 w;
	int r;

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

	if (!pdata)
		pdata = &davinci_i2c_platform_data_default;
	/* Introduce a delay, required for some boards (e.g Davinci EVM) */
	if (pdata->bus_delay)
		udelay(pdata->bus_delay);

	/* set the slave address */
	davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);

	dev->buf = msg->buf;
	dev->buf_len = msg->len;

	davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);

	init_completion(&dev->cmd_complete);
	dev->cmd_err = 0;

	/* Clear any pending interrupts by reading the IVR */
	stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG);

	/* Take I2C out of reset, configure it as master and set the
	 * start bit */
	flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST | DAVINCI_I2C_MDR_STT;

	/* if the slave address is ten bit address, enable XA bit */
	if (msg->flags & I2C_M_TEN)
		flag |= DAVINCI_I2C_MDR_XA;
	if (!(msg->flags & I2C_M_RD))
		flag |= DAVINCI_I2C_MDR_TRX;
	if (stop)
		flag |= DAVINCI_I2C_MDR_STP;

	/* Enable receive or transmit interrupts */
	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
	if (msg->flags & I2C_M_RD)
		MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
	else
		MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);

	/* write the data into mode register */
	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);

	r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
						      DAVINCI_I2C_TIMEOUT);
	dev->buf_len = 0;
	if (r < 0)
		return r;

	if (r == 0) {
		dev_err(dev->dev, "controller timed out\n");
		i2c_davinci_init(dev);
		return -ETIMEDOUT;
	}

	/* no error */
	if (likely(!dev->cmd_err))
		return msg->len;

	/* We have an error */
	if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
		i2c_davinci_init(dev);
		return -EIO;
	}

	if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
		if (msg->flags & I2C_M_IGNORE_NAK)
			return msg->len;
		if (stop) {
			w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
			MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
			davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
		}
		return -EREMOTEIO;
	}
	return -EIO;
}

/*
 * Prepare controller for a transaction and call i2c_davinci_xfer_msg
 */
static int
i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
	int i;
	int ret;

	dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);

	ret = i2c_davinci_wait_bus_not_busy(dev, 1);
	if (ret < 0) {
		dev_warn(dev->dev, "timeout waiting for bus ready\n");
		return ret;
	}

	for (i = 0; i < num; i++) {
		ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
		if (ret < 0)
			return ret;
	}

	dev_dbg(dev->dev, "%s:%d ret: %d\n", __func__, __LINE__, ret);

	return num;
}

static u32 i2c_davinci_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}

/*
 * Interrupt service routine. This gets called whenever an I2C interrupt
 * occurs.
 */
static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
{
	struct davinci_i2c_dev *dev = dev_id;
	u32 stat;
	int count = 0;
	u16 w;

	while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
		dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
		if (count++ == 100) {
			dev_warn(dev->dev, "Too much work in one IRQ\n");
			break;
		}

		switch (stat) {
		case DAVINCI_I2C_IVR_AL:
			dev->cmd_err |= DAVINCI_I2C_STR_AL;
			complete(&dev->cmd_complete);
			break;

		case DAVINCI_I2C_IVR_NACK:
			dev->cmd_err |= DAVINCI_I2C_STR_NACK;
			complete(&dev->cmd_complete);
			break;

		case DAVINCI_I2C_IVR_ARDY:
			davinci_i2c_write_reg(dev,
				DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
			complete(&dev->cmd_complete);
			break;

		case DAVINCI_I2C_IVR_RDR:
			if (dev->buf_len) {
				*dev->buf++ =
				    davinci_i2c_read_reg(dev,
							 DAVINCI_I2C_DRR_REG);
				dev->buf_len--;
				if (dev->buf_len)
					continue;

				davinci_i2c_write_reg(dev,
					DAVINCI_I2C_STR_REG,
					DAVINCI_I2C_IMR_RRDY);
			} else
				dev_err(dev->dev, "RDR IRQ while no "
					"data requested\n");
			break;

		case DAVINCI_I2C_IVR_XRDY:
			if (dev->buf_len) {
				davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
						      *dev->buf++);
				dev->buf_len--;
				if (dev->buf_len)
					continue;

				w = davinci_i2c_read_reg(dev,
							 DAVINCI_I2C_IMR_REG);
				MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
				davinci_i2c_write_reg(dev,
						      DAVINCI_I2C_IMR_REG,
						      w);
			} else
				dev_err(dev->dev, "TDR IRQ while no data to "
					"send\n");
			break;

		case DAVINCI_I2C_IVR_SCD:
			davinci_i2c_write_reg(dev,
				DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
			complete(&dev->cmd_complete);
			break;

		case DAVINCI_I2C_IVR_AAS:
			dev_warn(dev->dev, "Address as slave interrupt\n");
		}/* switch */
	}/* while */

	return count ? IRQ_HANDLED : IRQ_NONE;
}

static struct i2c_algorithm i2c_davinci_algo = {
	.master_xfer	= i2c_davinci_xfer,
	.functionality	= i2c_davinci_func,
};

static int davinci_i2c_probe(struct platform_device *pdev)
{
	struct davinci_i2c_dev *dev;
	struct i2c_adapter *adap;
	struct resource *mem, *irq, *ioarea;
	int r;

	/* NOTE: driver uses the static register mapping */
	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem) {
		dev_err(&pdev->dev, "no mem resource?\n");
		return -ENODEV;
	}

	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!irq) {
		dev_err(&pdev->dev, "no irq resource?\n");
		return -ENODEV;
	}

	ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
				    pdev->name);
	if (!ioarea) {
		dev_err(&pdev->dev, "I2C region already claimed\n");
		return -EBUSY;
	}

	dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
	if (!dev) {
		r = -ENOMEM;
		goto err_release_region;
	}

	dev->dev = get_device(&pdev->dev);
	dev->irq = irq->start;
	platform_set_drvdata(pdev, dev);

	dev->clk = clk_get(&pdev->dev, "I2CCLK");
	if (IS_ERR(dev->clk)) {
		r = -ENODEV;
		goto err_free_mem;
	}
	clk_enable(dev->clk);

	dev->base = (void __iomem *)IO_ADDRESS(mem->start);
	i2c_davinci_init(dev);

	r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
	if (r) {
		dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
		goto err_unuse_clocks;
	}

	adap = &dev->adapter;
	i2c_set_adapdata(adap, dev);
	adap->owner = THIS_MODULE;
	adap->class = I2C_CLASS_HWMON;
	strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
	adap->algo = &i2c_davinci_algo;
	adap->dev.parent = &pdev->dev;

	/* FIXME */
	adap->timeout = 1;

	adap->nr = pdev->id;
	r = i2c_add_numbered_adapter(adap);
	if (r) {
		dev_err(&pdev->dev, "failure adding adapter\n");
		goto err_free_irq;
	}

	return 0;

err_free_irq:
	free_irq(dev->irq, dev);
err_unuse_clocks:
	clk_disable(dev->clk);
	clk_put(dev->clk);
	dev->clk = NULL;
err_free_mem:
	platform_set_drvdata(pdev, NULL);
	put_device(&pdev->dev);
	kfree(dev);
err_release_region:
	release_mem_region(mem->start, (mem->end - mem->start) + 1);

	return r;
}

static int davinci_i2c_remove(struct platform_device *pdev)
{
	struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
	struct resource *mem;

	platform_set_drvdata(pdev, NULL);
	i2c_del_adapter(&dev->adapter);
	put_device(&pdev->dev);

	clk_disable(dev->clk);
	clk_put(dev->clk);
	dev->clk = NULL;

	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
	free_irq(IRQ_I2C, dev);
	kfree(dev);

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(mem->start, (mem->end - mem->start) + 1);
	return 0;
}

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:i2c_davinci");

static struct platform_driver davinci_i2c_driver = {
	.probe		= davinci_i2c_probe,
	.remove		= davinci_i2c_remove,
	.driver		= {
		.name	= "i2c_davinci",
		.owner	= THIS_MODULE,
	},
};

/* I2C may be needed to bring up other drivers */
static int __init davinci_i2c_init_driver(void)
{
	return platform_driver_register(&davinci_i2c_driver);
}
subsys_initcall(davinci_i2c_init_driver);

static void __exit davinci_i2c_exit_driver(void)
{
	platform_driver_unregister(&davinci_i2c_driver);
}
module_exit(davinci_i2c_exit_driver);

MODULE_AUTHOR("Texas Instruments India");
MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
MODULE_LICENSE("GPL");
Commit	Line	Data
95a7f10e VB	1	/*
	2	* TI DAVINCI I2C adapter driver.
	3	*
	4	* Copyright (C) 2006 Texas Instruments.
	5	* Copyright (C) 2007 MontaVista Software Inc.
	6	*
	7	* Updated by Vinod & Sudhakar Feb 2005
	8	*
	9	* ----------------------------------------------------------------------------
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License as published by
	13	* the Free Software Foundation; either version 2 of the License, or
	14	* (at your option) any later version.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	* GNU General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU General Public License
	22	* along with this program; if not, write to the Free Software
	23	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	24	* ----------------------------------------------------------------------------
	25	*
	26	*/
	27	#include <linux/kernel.h>
	28	#include <linux/module.h>
	29	#include <linux/delay.h>
	30	#include <linux/i2c.h>
	31	#include <linux/clk.h>
	32	#include <linux/errno.h>
	33	#include <linux/sched.h>
	34	#include <linux/err.h>
	35	#include <linux/interrupt.h>
	36	#include <linux/platform_device.h>
	37	#include <linux/io.h>
	38
	39	#include <asm/hardware.h>
	40	#include <asm/mach-types.h>
	41
	42	#include <asm/arch/i2c.h>
	43
	44	/* ----- global defines ----------------------------------------------- */
	45
	46	#define DAVINCI_I2C_TIMEOUT (1*HZ)
	47	#define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_AAS \| \
	48	DAVINCI_I2C_IMR_SCD \| \
	49	DAVINCI_I2C_IMR_ARDY \| \
	50	DAVINCI_I2C_IMR_NACK \| \
	51	DAVINCI_I2C_IMR_AL)
	52
	53	#define DAVINCI_I2C_OAR_REG 0x00
	54	#define DAVINCI_I2C_IMR_REG 0x04
	55	#define DAVINCI_I2C_STR_REG 0x08
	56	#define DAVINCI_I2C_CLKL_REG 0x0c
	57	#define DAVINCI_I2C_CLKH_REG 0x10
	58	#define DAVINCI_I2C_CNT_REG 0x14
	59	#define DAVINCI_I2C_DRR_REG 0x18
	60	#define DAVINCI_I2C_SAR_REG 0x1c
	61	#define DAVINCI_I2C_DXR_REG 0x20
	62	#define DAVINCI_I2C_MDR_REG 0x24
	63	#define DAVINCI_I2C_IVR_REG 0x28
	64	#define DAVINCI_I2C_EMDR_REG 0x2c
65	#define DAVINCI_I2C_PSC_REG 0x30
66
67	#define DAVINCI_I2C_IVR_AAS 0x07
68	#define DAVINCI_I2C_IVR_SCD 0x06
69	#define DAVINCI_I2C_IVR_XRDY 0x05
70	#define DAVINCI_I2C_IVR_RDR 0x04
71	#define DAVINCI_I2C_IVR_ARDY 0x03
72	#define DAVINCI_I2C_IVR_NACK 0x02
73	#define DAVINCI_I2C_IVR_AL 0x01
74
75	#define DAVINCI_I2C_STR_BB (1 << 12)
76	#define DAVINCI_I2C_STR_RSFULL (1 << 11)
77	#define DAVINCI_I2C_STR_SCD (1 << 5)
78	#define DAVINCI_I2C_STR_ARDY (1 << 2)
79	#define DAVINCI_I2C_STR_NACK (1 << 1)
80	#define DAVINCI_I2C_STR_AL (1 << 0)
81
82	#define DAVINCI_I2C_MDR_NACK (1 << 15)
83	#define DAVINCI_I2C_MDR_STT (1 << 13)
84	#define DAVINCI_I2C_MDR_STP (1 << 11)
85	#define DAVINCI_I2C_MDR_MST (1 << 10)
86	#define DAVINCI_I2C_MDR_TRX (1 << 9)
87	#define DAVINCI_I2C_MDR_XA (1 << 8)
88	#define DAVINCI_I2C_MDR_IRS (1 << 5)
89
90	#define DAVINCI_I2C_IMR_AAS (1 << 6)
91	#define DAVINCI_I2C_IMR_SCD (1 << 5)
92	#define DAVINCI_I2C_IMR_XRDY (1 << 4)
93	#define DAVINCI_I2C_IMR_RRDY (1 << 3)
94	#define DAVINCI_I2C_IMR_ARDY (1 << 2)
95	#define DAVINCI_I2C_IMR_NACK (1 << 1)
96	#define DAVINCI_I2C_IMR_AL (1 << 0)
97
98	#define MOD_REG_BIT(val, mask, set) do { \
99	if (set) { \
100	val \|= mask; \
101	} else { \
102	val &= ~mask; \
103	} \
104	} while (0)
105
106	struct davinci_i2c_dev {
107	struct device *dev;
108	void __iomem *base;
109	struct completion cmd_complete;
110	struct clk *clk;
111	int cmd_err;
112	u8 *buf;
113	size_t buf_len;
114	int irq;
115	struct i2c_adapter adapter;
116	};
117
118	/* default platform data to use if not supplied in the platform_device */
119	static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
120	.bus_freq = 100,
121	.bus_delay = 0,
122	};
123
124	static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
125	int reg, u16 val)
126	{
127	__raw_writew(val, i2c_dev->base + reg);
128	}
129
130	static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
131	{
132	return __raw_readw(i2c_dev->base + reg);
133	}
134
135	/*
136	* This functions configures I2C and brings I2C out of reset.
137	* This function is called during I2C init function. This function
138	* also gets called if I2C encounters any errors.
139	*/
140	static int i2c_davinci_init(struct davinci_i2c_dev *dev)
141	{
142	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
143	u16 psc;
144	u32 clk;
cc99ff70	145	u32 d;
95a7f10e VB	146	u32 clkh;
	147	u32 clkl;
	148	u32 input_clock = clk_get_rate(dev->clk);
	149	u16 w;
	150
	151	if (!pdata)
	152	pdata = &davinci_i2c_platform_data_default;
	153
	154	/* put I2C into reset */
	155	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
	156	MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
	157	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
	158
	159	/* NOTE: I2C Clock divider programming info
	160	* As per I2C specs the following formulas provide prescaler
	161	* and low/high divider values
	162	* input clk --> PSC Div -----------> ICCL/H Div --> output clock
	163	* module clk
	164	*
	165	* output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
	166	*
	167	* Thus,
	168	* (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
	169	*
	170	* where if PSC == 0, d = 7,
	171	* if PSC == 1, d = 6
	172	* if PSC > 1 , d = 5
	173	*/
	174
cc99ff70 TK	175	/* get minimum of 7 MHz clock, but max of 12 MHz */
	176	psc = (input_clock / 7000000) - 1;
	177	if ((input_clock / (psc + 1)) > 12000000)
	178	psc++; /* better to run under spec than over */
	179	d = (psc >= 2) ? 5 : 7 - psc;
95a7f10e	180
cc99ff70 TK	181	clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
cc99ff70 TK	182	clkh = clk >> 1;
95a7f10e VB	183	clkl = clk - clkh;
	184
	185	davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
	186	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
	187	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
	188
cc99ff70	189	dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
95a7f10e VB	190	dev_dbg(dev->dev, "PSC = %d\n",
	191	davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
	192	dev_dbg(dev->dev, "CLKL = %d\n",
	193	davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
	194	dev_dbg(dev->dev, "CLKH = %d\n",
	195	davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
cc99ff70 TK	196	dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
cc99ff70 TK	197	pdata->bus_freq, pdata->bus_delay);
95a7f10e VB	198
	199	/* Take the I2C module out of reset: */
	200	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
	201	MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
	202	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
	203
	204	/* Enable interrupts */
	205	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
	206
	207	return 0;
	208	}
	209
	210	/*
	211	* Waiting for bus not busy
	212	*/
	213	static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
	214	char allow_sleep)
	215	{
	216	unsigned long timeout;
	217
	218	timeout = jiffies + DAVINCI_I2C_TIMEOUT;
	219	while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
	220	& DAVINCI_I2C_STR_BB) {
	221	if (time_after(jiffies, timeout)) {
	222	dev_warn(dev->dev,
	223	"timeout waiting for bus ready\n");
	224	return -ETIMEDOUT;
	225	}
	226	if (allow_sleep)
	227	schedule_timeout(1);
	228	}
	229
	230	return 0;
	231	}
	232
	233	/*
	234	* Low level master read/write transaction. This function is called
	235	* from i2c_davinci_xfer.
	236	*/
	237	static int
	238	i2c_davinci_xfer_msg(struct i2c_adapter adap, struct i2c_msg msg, int stop)
	239	{
	240	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
	241	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
	242	u32 flag;
	243	u32 stat;
	244	u16 w;
	245	int r;
	246
	247	if (msg->len == 0)
	248	return -EINVAL;
	249
	250	if (!pdata)
	251	pdata = &davinci_i2c_platform_data_default;
	252	/* Introduce a delay, required for some boards (e.g Davinci EVM) */
	253	if (pdata->bus_delay)
	254	udelay(pdata->bus_delay);
	255
	256	/* set the slave address */
	257	davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
	258
	259	dev->buf = msg->buf;
	260	dev->buf_len = msg->len;
	261
262	davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
263
264	init_completion(&dev->cmd_complete);
265	dev->cmd_err = 0;
266
267	/* Clear any pending interrupts by reading the IVR */
268	stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG);
269
270	/* Take I2C out of reset, configure it as master and set the
271	* start bit */
272	flag = DAVINCI_I2C_MDR_IRS \| DAVINCI_I2C_MDR_MST \| DAVINCI_I2C_MDR_STT;
273
274	/* if the slave address is ten bit address, enable XA bit */
275	if (msg->flags & I2C_M_TEN)
276	flag \|= DAVINCI_I2C_MDR_XA;
277	if (!(msg->flags & I2C_M_RD))
278	flag \|= DAVINCI_I2C_MDR_TRX;
279	if (stop)
280	flag \|= DAVINCI_I2C_MDR_STP;
281
282	/* Enable receive or transmit interrupts */
283	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
284	if (msg->flags & I2C_M_RD)
285	MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
286	else
287	MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
288	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
289
290	/* write the data into mode register */
291	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
292
293	r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
294	DAVINCI_I2C_TIMEOUT);
295	dev->buf_len = 0;
296	if (r < 0)
297	return r;
298
299	if (r == 0) {
300	dev_err(dev->dev, "controller timed out\n");
301	i2c_davinci_init(dev);
302	return -ETIMEDOUT;
303	}
304
305	/* no error */
306	if (likely(!dev->cmd_err))
307	return msg->len;
308
309	/* We have an error */
310	if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
311	i2c_davinci_init(dev);
312	return -EIO;
313	}
314
315	if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
316	if (msg->flags & I2C_M_IGNORE_NAK)
317	return msg->len;
318	if (stop) {
319	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
320	MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
321	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
322	}
323	return -EREMOTEIO;
324	}
325	return -EIO;
326	}
327
328	/*
329	* Prepare controller for a transaction and call i2c_davinci_xfer_msg
330	*/
331	static int
332	i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
333	{
334	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
335	int i;
336	int ret;
337
08882d20	338	dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
95a7f10e VB	339
	340	ret = i2c_davinci_wait_bus_not_busy(dev, 1);
	341	if (ret < 0) {
	342	dev_warn(dev->dev, "timeout waiting for bus ready\n");
	343	return ret;
	344	}
	345
	346	for (i = 0; i < num; i++) {
	347	ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
	348	if (ret < 0)
	349	return ret;
	350	}
	351
08882d20	352	dev_dbg(dev->dev, "%s:%d ret: %d\n", __func__, __LINE__, ret);
95a7f10e VB	353
	354	return num;
	355	}
	356
	357	static u32 i2c_davinci_func(struct i2c_adapter *adap)
	358	{
	359	return I2C_FUNC_I2C \| (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
	360	}
	361
	362	/*
	363	* Interrupt service routine. This gets called whenever an I2C interrupt
	364	* occurs.
	365	*/
	366	static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
	367	{
	368	struct davinci_i2c_dev *dev = dev_id;
	369	u32 stat;
	370	int count = 0;
	371	u16 w;
	372
	373	while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
08882d20	374	dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
95a7f10e VB	375	if (count++ == 100) {
	376	dev_warn(dev->dev, "Too much work in one IRQ\n");
	377	break;
	378	}
	379
	380	switch (stat) {
	381	case DAVINCI_I2C_IVR_AL:
	382	dev->cmd_err \|= DAVINCI_I2C_STR_AL;
	383	complete(&dev->cmd_complete);
	384	break;
	385
	386	case DAVINCI_I2C_IVR_NACK:
	387	dev->cmd_err \|= DAVINCI_I2C_STR_NACK;
	388	complete(&dev->cmd_complete);
	389	break;
	390
	391	case DAVINCI_I2C_IVR_ARDY:
b73a9aec TK	392	davinci_i2c_write_reg(dev,
b73a9aec TK	393	DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
95a7f10e VB	394	complete(&dev->cmd_complete);
	395	break;
	396
	397	case DAVINCI_I2C_IVR_RDR:
	398	if (dev->buf_len) {
	399	*dev->buf++ =
	400	davinci_i2c_read_reg(dev,
	401	DAVINCI_I2C_DRR_REG);
	402	dev->buf_len--;
	403	if (dev->buf_len)
	404	continue;
	405
95a7f10e	406	davinci_i2c_write_reg(dev,
b73a9aec TK	407	DAVINCI_I2C_STR_REG,
b73a9aec TK	408	DAVINCI_I2C_IMR_RRDY);
95a7f10e	409	} else
fce3ff03	410	dev_err(dev->dev, "RDR IRQ while no "
95a7f10e VB	411	"data requested\n");
	412	break;
	413
	414	case DAVINCI_I2C_IVR_XRDY:
	415	if (dev->buf_len) {
	416	davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
	417	*dev->buf++);
	418	dev->buf_len--;
	419	if (dev->buf_len)
	420	continue;
	421
	422	w = davinci_i2c_read_reg(dev,
	423	DAVINCI_I2C_IMR_REG);
	424	MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
	425	davinci_i2c_write_reg(dev,
	426	DAVINCI_I2C_IMR_REG,
	427	w);
	428	} else
fce3ff03	429	dev_err(dev->dev, "TDR IRQ while no data to "
95a7f10e VB	430	"send\n");
	431	break;
	432
	433	case DAVINCI_I2C_IVR_SCD:
b73a9aec TK	434	davinci_i2c_write_reg(dev,
b73a9aec TK	435	DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
95a7f10e VB	436	complete(&dev->cmd_complete);
	437	break;
	438
	439	case DAVINCI_I2C_IVR_AAS:
	440	dev_warn(dev->dev, "Address as slave interrupt\n");
	441	}/* switch */
	442	}/* while */
	443
	444	return count ? IRQ_HANDLED : IRQ_NONE;
	445	}
	446
	447	static struct i2c_algorithm i2c_davinci_algo = {
	448	.master_xfer = i2c_davinci_xfer,
	449	.functionality = i2c_davinci_func,
	450	};
	451
	452	static int davinci_i2c_probe(struct platform_device *pdev)
	453	{
	454	struct davinci_i2c_dev *dev;
	455	struct i2c_adapter *adap;
	456	struct resource mem, irq, *ioarea;
	457	int r;
	458
	459	/* NOTE: driver uses the static register mapping */
	460	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	461	if (!mem) {
	462	dev_err(&pdev->dev, "no mem resource?\n");
	463	return -ENODEV;
	464	}
	465
	466	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	467	if (!irq) {
	468	dev_err(&pdev->dev, "no irq resource?\n");
	469	return -ENODEV;
	470	}
	471
	472	ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
	473	pdev->name);
	474	if (!ioarea) {
	475	dev_err(&pdev->dev, "I2C region already claimed\n");
	476	return -EBUSY;
	477	}
	478
	479	dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
	480	if (!dev) {
	481	r = -ENOMEM;
	482	goto err_release_region;
	483	}
	484
	485	dev->dev = get_device(&pdev->dev);
	486	dev->irq = irq->start;
	487	platform_set_drvdata(pdev, dev);
	488
	489	dev->clk = clk_get(&pdev->dev, "I2CCLK");
	490	if (IS_ERR(dev->clk)) {
	491	r = -ENODEV;
	492	goto err_free_mem;
	493	}
	494	clk_enable(dev->clk);
	495
	496	dev->base = (void __iomem *)IO_ADDRESS(mem->start);
	497	i2c_davinci_init(dev);
	498
	499	r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
500	if (r) {
501	dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
502	goto err_unuse_clocks;
503	}
504
505	adap = &dev->adapter;
506	i2c_set_adapdata(adap, dev);
507	adap->owner = THIS_MODULE;
508	adap->class = I2C_CLASS_HWMON;
509	strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
510	adap->algo = &i2c_davinci_algo;
511	adap->dev.parent = &pdev->dev;
512
513	/* FIXME */
514	adap->timeout = 1;
95a7f10e VB	515
	516	adap->nr = pdev->id;
	517	r = i2c_add_numbered_adapter(adap);
	518	if (r) {
	519	dev_err(&pdev->dev, "failure adding adapter\n");
	520	goto err_free_irq;
	521	}
	522
	523	return 0;
	524
	525	err_free_irq:
	526	free_irq(dev->irq, dev);
	527	err_unuse_clocks:
	528	clk_disable(dev->clk);
	529	clk_put(dev->clk);
	530	dev->clk = NULL;
	531	err_free_mem:
	532	platform_set_drvdata(pdev, NULL);
	533	put_device(&pdev->dev);
	534	kfree(dev);
	535	err_release_region:
	536	release_mem_region(mem->start, (mem->end - mem->start) + 1);
	537
	538	return r;
	539	}
	540
	541	static int davinci_i2c_remove(struct platform_device *pdev)
	542	{
	543	struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
	544	struct resource *mem;
	545
	546	platform_set_drvdata(pdev, NULL);
	547	i2c_del_adapter(&dev->adapter);
	548	put_device(&pdev->dev);
	549
	550	clk_disable(dev->clk);
	551	clk_put(dev->clk);
	552	dev->clk = NULL;
	553
	554	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
	555	free_irq(IRQ_I2C, dev);
	556	kfree(dev);
	557
	558	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	559	release_mem_region(mem->start, (mem->end - mem->start) + 1);
	560	return 0;
	561	}
	562
add8eda7 KS	563	/* work with hotplug and coldplug */
	564	MODULE_ALIAS("platform:i2c_davinci");
	565
95a7f10e VB	566	static struct platform_driver davinci_i2c_driver = {
	567	.probe = davinci_i2c_probe,
	568	.remove = davinci_i2c_remove,
	569	.driver = {
	570	.name = "i2c_davinci",
	571	.owner = THIS_MODULE,
	572	},
	573	};
	574
	575	/* I2C may be needed to bring up other drivers */
	576	static int __init davinci_i2c_init_driver(void)
	577	{
	578	return platform_driver_register(&davinci_i2c_driver);
	579	}
	580	subsys_initcall(davinci_i2c_init_driver);
	581
	582	static void __exit davinci_i2c_exit_driver(void)
	583	{
	584	platform_driver_unregister(&davinci_i2c_driver);
	585	}
	586	module_exit(davinci_i2c_exit_driver);
	587
	588	MODULE_AUTHOR("Texas Instruments India");
	589	MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
	590	MODULE_LICENSE("GPL");