drivers/media/usb/stk1160/stk1160-i2c.c - linux - Git at Google

 /*
  * STK1160 driver
  *
  * Copyright (C) 2012 Ezequiel Garcia
  * <elezegarcia--a.t--gmail.com>
  *
  * Based on Easycap driver by R.M. Thomas
  *	Copyright (C) 2010 R.M. Thomas
  *	<rmthomas--a.t--sciolus.org>
  *
  * 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/module.h>
 #include <linux/usb.h>
 #include <linux/i2c.h>

 #include "stk1160.h"
 #include "stk1160-reg.h"

 static unsigned int i2c_debug;
 module_param(i2c_debug, int, 0644);
 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");

 #define dprintk_i2c(fmt, args...)				\
 do {								\
 	if (i2c_debug)						\
 		printk(KERN_DEBUG fmt, ##args);			\
 } while (0)

 static int stk1160_i2c_busy_wait(struct stk1160 *dev, u8 wait_bit_mask)
 {
 	unsigned long end;
 	u8 flag;

 	/* Wait until read/write finish bit is set */
 	end = jiffies + msecs_to_jiffies(STK1160_I2C_TIMEOUT);
 	while (time_is_after_jiffies(end)) {

 		stk1160_read_reg(dev, STK1160_SICTL+1, &flag);
 		/* read/write done? */
 		if (flag & wait_bit_mask)
 			goto done;

 		usleep_range(10 * USEC_PER_MSEC, 20 * USEC_PER_MSEC);
 	}

 	return -ETIMEDOUT;

 done:
 	return 0;
 }

 static int stk1160_i2c_write_reg(struct stk1160 *dev, u8 addr,
 		u8 reg, u8 value)
 {
 	int rc;

 	/* Set serial device address */
 	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
 	if (rc < 0)
 		return rc;

 	/* Set i2c device register sub-address */
 	rc = stk1160_write_reg(dev, STK1160_SBUSW_WA, reg);
 	if (rc < 0)
 		return rc;

 	/* Set i2c device register value */
 	rc = stk1160_write_reg(dev, STK1160_SBUSW_WD, value);
 	if (rc < 0)
 		return rc;

 	/* Start write now */
 	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x01);
 	if (rc < 0)
 		return rc;

 	rc = stk1160_i2c_busy_wait(dev, 0x04);
 	if (rc < 0)
 		return rc;

 	return 0;
 }

 static int stk1160_i2c_read_reg(struct stk1160 *dev, u8 addr,
 		u8 reg, u8 *value)
 {
 	int rc;

 	/* Set serial device address */
 	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
 	if (rc < 0)
 		return rc;

 	/* Set i2c device register sub-address */
 	rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, reg);
 	if (rc < 0)
 		return rc;

 	/* Start read now */
 	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
 	if (rc < 0)
 		return rc;

 	rc = stk1160_i2c_busy_wait(dev, 0x01);
 	if (rc < 0)
 		return rc;

 	rc = stk1160_read_reg(dev, STK1160_SBUSR_RD, value);
 	if (rc < 0)
 		return rc;

 	return 0;
 }

 /*
  * stk1160_i2c_check_for_device()
  * check if there is a i2c_device at the supplied address
  */
 static int stk1160_i2c_check_for_device(struct stk1160 *dev,
 		unsigned char addr)
 {
 	int rc;

 	/* Set serial device address */
 	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
 	if (rc < 0)
 		return rc;

 	/* Set device sub-address, we'll chip version reg */
 	rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, 0x00);
 	if (rc < 0)
 		return rc;

 	/* Start read now */
 	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
 	if (rc < 0)
 		return rc;

 	rc = stk1160_i2c_busy_wait(dev, 0x01);
 	if (rc < 0)
 		return -ENODEV;

 	return 0;
 }

 /*
  * stk1160_i2c_xfer()
  * the main i2c transfer function
  */
 static int stk1160_i2c_xfer(struct i2c_adapter *i2c_adap,
 			   struct i2c_msg msgs[], int num)
 {
 	struct stk1160 *dev = i2c_adap->algo_data;
 	int addr, rc, i;

 	for (i = 0; i < num; i++) {
 		addr = msgs[i].addr << 1;
 		dprintk_i2c("%s: addr=%x", __func__, addr);

 		if (!msgs[i].len) {
 			/* no len: check only for device presence */
 			rc = stk1160_i2c_check_for_device(dev, addr);
 			if (rc < 0) {
 				dprintk_i2c(" no device\n");
 				return rc;
 			}

 		} else if (msgs[i].flags & I2C_M_RD) {
 			/* read request without preceding register selection */
 			dprintk_i2c(" subaddr not selected");
 			rc = -EOPNOTSUPP;
 			goto err;

 		} else if (i + 1 < num && msgs[i].len <= 2 &&
 			   (msgs[i + 1].flags & I2C_M_RD) &&
 			   msgs[i].addr == msgs[i + 1].addr) {

 			if (msgs[i].len != 1 || msgs[i + 1].len != 1) {
 				dprintk_i2c(" len not supported");
 				rc = -EOPNOTSUPP;
 				goto err;
 			}

 			dprintk_i2c(" subaddr=%x", msgs[i].buf[0]);

 			rc = stk1160_i2c_read_reg(dev, addr, msgs[i].buf[0],
 				msgs[i + 1].buf);

 			dprintk_i2c(" read=%x", *msgs[i + 1].buf);

 			/* consumed two msgs, so we skip one of them */
 			i++;

 		} else {
 			if (msgs[i].len != 2) {
 				dprintk_i2c(" len not supported");
 				rc = -EOPNOTSUPP;
 				goto err;
 			}

 			dprintk_i2c(" subaddr=%x write=%x",
 				msgs[i].buf[0],  msgs[i].buf[1]);

 			rc = stk1160_i2c_write_reg(dev, addr, msgs[i].buf[0],
 				msgs[i].buf[1]);
 		}

 		if (rc < 0)
 			goto err;
 		dprintk_i2c(" OK\n");
 	}

 	return num;
 err:
 	dprintk_i2c(" ERROR: %d\n", rc);
 	return num;
 }

 /*
  * functionality(), what da heck is this?
  */
 static u32 functionality(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_SMBUS_EMUL;
 }

 static const struct i2c_algorithm algo = {
 	.master_xfer   = stk1160_i2c_xfer,
 	.functionality = functionality,
 };

 static const struct i2c_adapter adap_template = {
 	.owner = THIS_MODULE,
 	.name = "stk1160",
 	.algo = &algo,
 };

 static const struct i2c_client client_template = {
 	.name = "stk1160 internal",
 };

 /*
  * stk1160_i2c_register()
  * register i2c bus
  */
 int stk1160_i2c_register(struct stk1160 *dev)
 {
 	int rc;

 	dev->i2c_adap = adap_template;
 	dev->i2c_adap.dev.parent = dev->dev;
 	strscpy(dev->i2c_adap.name, "stk1160", sizeof(dev->i2c_adap.name));
 	dev->i2c_adap.algo_data = dev;

 	i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);

 	rc = i2c_add_adapter(&dev->i2c_adap);
 	if (rc < 0) {
 		stk1160_err("cannot add i2c adapter (%d)\n", rc);
 		return rc;
 	}

 	dev->i2c_client = client_template;
 	dev->i2c_client.adapter = &dev->i2c_adap;

 	/* Set i2c clock divider device address */
 	stk1160_write_reg(dev, STK1160_SICTL_CD,  0x0f);

 	/* ??? */
 	stk1160_write_reg(dev, STK1160_ASIC + 3,  0x00);

 	return 0;
 }

 /*
  * stk1160_i2c_unregister()
  * unregister i2c_bus
  */
 int stk1160_i2c_unregister(struct stk1160 *dev)
 {
 	i2c_del_adapter(&dev->i2c_adap);
 	return 0;
 }
	/*
	* STK1160 driver
	*
	* Copyright (C) 2012 Ezequiel Garcia
	* <elezegarcia--a.t--gmail.com>
	*
	* Based on Easycap driver by R.M. Thomas
	* Copyright (C) 2010 R.M. Thomas
	* <rmthomas--a.t--sciolus.org>
	*
	* 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/module.h>
	#include <linux/usb.h>
	#include <linux/i2c.h>

	#include "stk1160.h"
	#include "stk1160-reg.h"

	static unsigned int i2c_debug;
	module_param(i2c_debug, int, 0644);
	MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");

	#define dprintk_i2c(fmt, args...) \
	do { \
	if (i2c_debug) \
	printk(KERN_DEBUG fmt, ##args); \
	} while (0)

	static int stk1160_i2c_busy_wait(struct stk1160 *dev, u8 wait_bit_mask)
	{
	unsigned long end;
	u8 flag;

	/* Wait until read/write finish bit is set */
	end = jiffies + msecs_to_jiffies(STK1160_I2C_TIMEOUT);
	while (time_is_after_jiffies(end)) {

	stk1160_read_reg(dev, STK1160_SICTL+1, &flag);
	/* read/write done? */
	if (flag & wait_bit_mask)
	goto done;

	usleep_range(10 * USEC_PER_MSEC, 20 * USEC_PER_MSEC);
	}

	return -ETIMEDOUT;

	done:
	return 0;
	}

	static int stk1160_i2c_write_reg(struct stk1160 *dev, u8 addr,
	u8 reg, u8 value)
	{
	int rc;

	/* Set serial device address */
	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
	if (rc < 0)
	return rc;

	/* Set i2c device register sub-address */
	rc = stk1160_write_reg(dev, STK1160_SBUSW_WA, reg);
	if (rc < 0)
	return rc;

	/* Set i2c device register value */
	rc = stk1160_write_reg(dev, STK1160_SBUSW_WD, value);
	if (rc < 0)
	return rc;

	/* Start write now */
	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x01);
	if (rc < 0)
	return rc;

	rc = stk1160_i2c_busy_wait(dev, 0x04);
	if (rc < 0)
	return rc;

	return 0;
	}

	static int stk1160_i2c_read_reg(struct stk1160 *dev, u8 addr,
	u8 reg, u8 *value)
	{
	int rc;

	/* Set serial device address */
	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
	if (rc < 0)
	return rc;

	/* Set i2c device register sub-address */
	rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, reg);
	if (rc < 0)
	return rc;

	/* Start read now */
	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
	if (rc < 0)
	return rc;

	rc = stk1160_i2c_busy_wait(dev, 0x01);
	if (rc < 0)
	return rc;

	rc = stk1160_read_reg(dev, STK1160_SBUSR_RD, value);
	if (rc < 0)
	return rc;

	return 0;
	}

	/*
	* stk1160_i2c_check_for_device()
	* check if there is a i2c_device at the supplied address
	*/
	static int stk1160_i2c_check_for_device(struct stk1160 *dev,
	unsigned char addr)
	{
	int rc;

	/* Set serial device address */
	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
	if (rc < 0)
	return rc;

	/* Set device sub-address, we'll chip version reg */
	rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, 0x00);
	if (rc < 0)
	return rc;

	/* Start read now */
	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
	if (rc < 0)
	return rc;

	rc = stk1160_i2c_busy_wait(dev, 0x01);
	if (rc < 0)
	return -ENODEV;

	return 0;
	}

	/*
	* stk1160_i2c_xfer()
	* the main i2c transfer function
	*/
	static int stk1160_i2c_xfer(struct i2c_adapter *i2c_adap,
	struct i2c_msg msgs[], int num)
	{
	struct stk1160 *dev = i2c_adap->algo_data;
	int addr, rc, i;

	for (i = 0; i < num; i++) {
	addr = msgs[i].addr << 1;
	dprintk_i2c("%s: addr=%x", __func__, addr);

	if (!msgs[i].len) {
	/* no len: check only for device presence */
	rc = stk1160_i2c_check_for_device(dev, addr);
	if (rc < 0) {
	dprintk_i2c(" no device\n");
	return rc;
	}

	} else if (msgs[i].flags & I2C_M_RD) {
	/* read request without preceding register selection */
	dprintk_i2c(" subaddr not selected");
	rc = -EOPNOTSUPP;
	goto err;

	} else if (i + 1 < num && msgs[i].len <= 2 &&
	(msgs[i + 1].flags & I2C_M_RD) &&
	msgs[i].addr == msgs[i + 1].addr) {

	if (msgs[i].len != 1 \|\| msgs[i + 1].len != 1) {
	dprintk_i2c(" len not supported");
	rc = -EOPNOTSUPP;
	goto err;
	}

	dprintk_i2c(" subaddr=%x", msgs[i].buf[0]);

	rc = stk1160_i2c_read_reg(dev, addr, msgs[i].buf[0],
	msgs[i + 1].buf);

	dprintk_i2c(" read=%x", *msgs[i + 1].buf);

	/* consumed two msgs, so we skip one of them */
	i++;

	} else {
	if (msgs[i].len != 2) {
	dprintk_i2c(" len not supported");
	rc = -EOPNOTSUPP;
	goto err;
	}

	dprintk_i2c(" subaddr=%x write=%x",
	msgs[i].buf[0], msgs[i].buf[1]);

	rc = stk1160_i2c_write_reg(dev, addr, msgs[i].buf[0],
	msgs[i].buf[1]);
	}

	if (rc < 0)
	goto err;
	dprintk_i2c(" OK\n");
	}

	return num;
	err:
	dprintk_i2c(" ERROR: %d\n", rc);
	return num;
	}

	/*
	* functionality(), what da heck is this?
	*/
	static u32 functionality(struct i2c_adapter *adap)
	{
	return I2C_FUNC_SMBUS_EMUL;
	}

	static const struct i2c_algorithm algo = {
	.master_xfer = stk1160_i2c_xfer,
	.functionality = functionality,
	};

	static const struct i2c_adapter adap_template = {
	.owner = THIS_MODULE,
	.name = "stk1160",
	.algo = &algo,
	};

	static const struct i2c_client client_template = {
	.name = "stk1160 internal",
	};

	/*
	* stk1160_i2c_register()
	* register i2c bus
	*/
	int stk1160_i2c_register(struct stk1160 *dev)
	{
	int rc;

	dev->i2c_adap = adap_template;
	dev->i2c_adap.dev.parent = dev->dev;
	strscpy(dev->i2c_adap.name, "stk1160", sizeof(dev->i2c_adap.name));
	dev->i2c_adap.algo_data = dev;

	i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);

	rc = i2c_add_adapter(&dev->i2c_adap);
	if (rc < 0) {
	stk1160_err("cannot add i2c adapter (%d)\n", rc);
	return rc;
	}

	dev->i2c_client = client_template;
	dev->i2c_client.adapter = &dev->i2c_adap;

	/* Set i2c clock divider device address */
	stk1160_write_reg(dev, STK1160_SICTL_CD, 0x0f);

	/* ??? */
	stk1160_write_reg(dev, STK1160_ASIC + 3, 0x00);

	return 0;
	}

	/*
	* stk1160_i2c_unregister()
	* unregister i2c_bus
	*/
	int stk1160_i2c_unregister(struct stk1160 *dev)
	{
	i2c_del_adapter(&dev->i2c_adap);
	return 0;
	}