295 lines
6.1 KiB
C
295 lines
6.1 KiB
C
/*
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* STK1160 driver
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*
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* Copyright (C) 2012 Ezequiel Garcia
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* <elezegarcia--a.t--gmail.com>
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*
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* Based on Easycap driver by R.M. Thomas
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* Copyright (C) 2010 R.M. Thomas
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* <rmthomas--a.t--sciolus.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/module.h>
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#include <linux/usb.h>
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#include <linux/i2c.h>
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#include "stk1160.h"
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#include "stk1160-reg.h"
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static unsigned int i2c_debug;
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module_param(i2c_debug, int, 0644);
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MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
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#define dprintk_i2c(fmt, args...) \
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do { \
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if (i2c_debug) \
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printk(KERN_DEBUG fmt, ##args); \
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} while (0)
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static int stk1160_i2c_busy_wait(struct stk1160 *dev, u8 wait_bit_mask)
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{
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unsigned long end;
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u8 flag;
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/* Wait until read/write finish bit is set */
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end = jiffies + msecs_to_jiffies(STK1160_I2C_TIMEOUT);
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while (time_is_after_jiffies(end)) {
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stk1160_read_reg(dev, STK1160_SICTL+1, &flag);
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/* read/write done? */
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if (flag & wait_bit_mask)
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goto done;
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usleep_range(10 * USEC_PER_MSEC, 20 * USEC_PER_MSEC);
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}
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return -ETIMEDOUT;
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done:
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return 0;
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}
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static int stk1160_i2c_write_reg(struct stk1160 *dev, u8 addr,
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u8 reg, u8 value)
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{
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int rc;
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/* Set serial device address */
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rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
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if (rc < 0)
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return rc;
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/* Set i2c device register sub-address */
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rc = stk1160_write_reg(dev, STK1160_SBUSW_WA, reg);
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if (rc < 0)
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return rc;
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/* Set i2c device register value */
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rc = stk1160_write_reg(dev, STK1160_SBUSW_WD, value);
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if (rc < 0)
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return rc;
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/* Start write now */
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rc = stk1160_write_reg(dev, STK1160_SICTL, 0x01);
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if (rc < 0)
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return rc;
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rc = stk1160_i2c_busy_wait(dev, 0x04);
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if (rc < 0)
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return rc;
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return 0;
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}
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static int stk1160_i2c_read_reg(struct stk1160 *dev, u8 addr,
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u8 reg, u8 *value)
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{
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int rc;
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/* Set serial device address */
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rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
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if (rc < 0)
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return rc;
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/* Set i2c device register sub-address */
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rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, reg);
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if (rc < 0)
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return rc;
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/* Start read now */
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rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
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if (rc < 0)
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return rc;
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rc = stk1160_i2c_busy_wait(dev, 0x01);
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if (rc < 0)
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return rc;
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stk1160_read_reg(dev, STK1160_SBUSR_RD, value);
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if (rc < 0)
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return rc;
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return 0;
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}
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/*
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* stk1160_i2c_check_for_device()
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* check if there is a i2c_device at the supplied address
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*/
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static int stk1160_i2c_check_for_device(struct stk1160 *dev,
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unsigned char addr)
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{
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int rc;
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/* Set serial device address */
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rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
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if (rc < 0)
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return rc;
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/* Set device sub-address, we'll chip version reg */
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rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, 0x00);
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if (rc < 0)
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return rc;
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/* Start read now */
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rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
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if (rc < 0)
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return rc;
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rc = stk1160_i2c_busy_wait(dev, 0x01);
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if (rc < 0)
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return -ENODEV;
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return 0;
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}
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/*
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* stk1160_i2c_xfer()
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* the main i2c transfer function
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*/
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static int stk1160_i2c_xfer(struct i2c_adapter *i2c_adap,
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struct i2c_msg msgs[], int num)
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{
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struct stk1160 *dev = i2c_adap->algo_data;
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int addr, rc, i;
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for (i = 0; i < num; i++) {
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addr = msgs[i].addr << 1;
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dprintk_i2c("%s: addr=%x", __func__, addr);
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if (!msgs[i].len) {
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/* no len: check only for device presence */
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rc = stk1160_i2c_check_for_device(dev, addr);
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if (rc < 0) {
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dprintk_i2c(" no device\n");
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return rc;
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}
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} else if (msgs[i].flags & I2C_M_RD) {
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/* read request without preceding register selection */
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dprintk_i2c(" subaddr not selected");
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rc = -EOPNOTSUPP;
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goto err;
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} else if (i + 1 < num && msgs[i].len <= 2 &&
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(msgs[i + 1].flags & I2C_M_RD) &&
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msgs[i].addr == msgs[i + 1].addr) {
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if (msgs[i].len != 1 || msgs[i + 1].len != 1) {
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dprintk_i2c(" len not supported");
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rc = -EOPNOTSUPP;
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goto err;
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}
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dprintk_i2c(" subaddr=%x", msgs[i].buf[0]);
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rc = stk1160_i2c_read_reg(dev, addr, msgs[i].buf[0],
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msgs[i + 1].buf);
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dprintk_i2c(" read=%x", *msgs[i + 1].buf);
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/* consumed two msgs, so we skip one of them */
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i++;
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} else {
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if (msgs[i].len != 2) {
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dprintk_i2c(" len not supported");
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rc = -EOPNOTSUPP;
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goto err;
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}
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dprintk_i2c(" subaddr=%x write=%x",
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msgs[i].buf[0], msgs[i].buf[1]);
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rc = stk1160_i2c_write_reg(dev, addr, msgs[i].buf[0],
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msgs[i].buf[1]);
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}
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if (rc < 0)
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goto err;
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dprintk_i2c(" OK\n");
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}
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return num;
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err:
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dprintk_i2c(" ERROR: %d\n", rc);
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return num;
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}
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/*
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* functionality(), what da heck is this?
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*/
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static u32 functionality(struct i2c_adapter *adap)
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{
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return I2C_FUNC_SMBUS_EMUL;
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}
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static struct i2c_algorithm algo = {
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.master_xfer = stk1160_i2c_xfer,
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.functionality = functionality,
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};
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static struct i2c_adapter adap_template = {
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.owner = THIS_MODULE,
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.name = "stk1160",
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.algo = &algo,
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};
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static struct i2c_client client_template = {
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.name = "stk1160 internal",
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};
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/*
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* stk1160_i2c_register()
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* register i2c bus
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*/
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int stk1160_i2c_register(struct stk1160 *dev)
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{
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int rc;
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dev->i2c_adap = adap_template;
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dev->i2c_adap.dev.parent = dev->dev;
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strcpy(dev->i2c_adap.name, "stk1160");
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dev->i2c_adap.algo_data = dev;
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i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
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rc = i2c_add_adapter(&dev->i2c_adap);
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if (rc < 0) {
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stk1160_err("cannot add i2c adapter (%d)\n", rc);
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return rc;
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}
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dev->i2c_client = client_template;
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dev->i2c_client.adapter = &dev->i2c_adap;
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/* Set i2c clock divider device address */
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stk1160_write_reg(dev, STK1160_SICTL_CD, 0x0f);
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/* ??? */
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stk1160_write_reg(dev, STK1160_ASIC + 3, 0x00);
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return 0;
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}
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/*
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* stk1160_i2c_unregister()
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* unregister i2c_bus
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*/
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int stk1160_i2c_unregister(struct stk1160 *dev)
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{
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i2c_del_adapter(&dev->i2c_adap);
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return 0;
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}
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