diff options
Diffstat (limited to 'drivers/media/usb/stk1160/stk1160-i2c.c')
| -rw-r--r-- | drivers/media/usb/stk1160/stk1160-i2c.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/drivers/media/usb/stk1160/stk1160-i2c.c b/drivers/media/usb/stk1160/stk1160-i2c.c new file mode 100644 index 0000000..850cf28 --- /dev/null +++ b/drivers/media/usb/stk1160/stk1160-i2c.c @@ -0,0 +1,294 @@ +/* + * 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; +} |