- 根目录:
- drivers
- media
- usb
- stk1160
- stk1160-i2c.c
/*
* 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 struct i2c_algorithm algo = {
.master_xfer = stk1160_i2c_xfer,
.functionality = functionality,
};
static struct i2c_adapter adap_template = {
.owner = THIS_MODULE,
.name = "stk1160",
.algo = &algo,
};
static 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;
strcpy(dev->i2c_adap.name, "stk1160");
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;
}