LXR linux/drivers/media/usb/stk1160/stk1160-i2c.c

   1/*
   2 * STK1160 driver
   3 *
   4 * Copyright (C) 2012 Ezequiel Garcia
   5 * <elezegarcia--a.t--gmail.com>
   6 *
   7 * Based on Easycap driver by R.M. Thomas
   8 *      Copyright (C) 2010 R.M. Thomas
   9 *      <rmthomas--a.t--sciolus.org>
  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 */
  22
  23#include <linux/module.h>
  24#include <linux/usb.h>
  25#include <linux/i2c.h>
  26
  27#include "stk1160.h"
  28#include "stk1160-reg.h"
  29
  30static unsigned int i2c_debug;
  31module_param(i2c_debug, int, 0644);
  32MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
  33
  34#define dprintk_i2c(fmt, args...)                               \
  35do {                                                            \
  36        if (i2c_debug)                                          \
  37                printk(KERN_DEBUG fmt, ##args);                 \
  38} while (0)
  39
  40static int stk1160_i2c_busy_wait(struct stk1160 *dev, u8 wait_bit_mask)
  41{
  42        unsigned long end;
  43        u8 flag;
  44
  45        /* Wait until read/write finish bit is set */
  46        end = jiffies + msecs_to_jiffies(STK1160_I2C_TIMEOUT);
  47        while (time_is_after_jiffies(end)) {
  48
  49                stk1160_read_reg(dev, STK1160_SICTL+1, &flag);
  50                /* read/write done? */
  51                if (flag & wait_bit_mask)
  52                        goto done;
  53
  54                usleep_range(10 * USEC_PER_MSEC, 20 * USEC_PER_MSEC);
  55        }
  56
  57        return -ETIMEDOUT;
  58
  59done:
  60        return 0;
  61}
  62
  63static int stk1160_i2c_write_reg(struct stk1160 *dev, u8 addr,
  64                u8 reg, u8 value)
  65{
  66        int rc;
  67
  68        /* Set serial device address */
  69        rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
  70        if (rc < 0)
  71                return rc;
  72
  73        /* Set i2c device register sub-address */
  74        rc = stk1160_write_reg(dev, STK1160_SBUSW_WA, reg);
  75        if (rc < 0)
  76                return rc;
  77
  78        /* Set i2c device register value */
  79        rc = stk1160_write_reg(dev, STK1160_SBUSW_WD, value);
  80        if (rc < 0)
  81                return rc;
  82
  83        /* Start write now */
  84        rc = stk1160_write_reg(dev, STK1160_SICTL, 0x01);
  85        if (rc < 0)
  86                return rc;
  87
  88        rc = stk1160_i2c_busy_wait(dev, 0x04);
  89        if (rc < 0)
  90                return rc;
  91
  92        return 0;
  93}
  94
  95static int stk1160_i2c_read_reg(struct stk1160 *dev, u8 addr,
  96                u8 reg, u8 *value)
  97{
  98        int rc;
  99
 100        /* Set serial device address */
 101        rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
 102        if (rc < 0)
 103                return rc;
 104
 105        /* Set i2c device register sub-address */
 106        rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, reg);
 107        if (rc < 0)
 108                return rc;
 109
 110        /* Start read now */
 111        rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
 112        if (rc < 0)
 113                return rc;
 114
 115        rc = stk1160_i2c_busy_wait(dev, 0x01);
 116        if (rc < 0)
 117                return rc;
 118
 119        rc = stk1160_read_reg(dev, STK1160_SBUSR_RD, value);
 120        if (rc < 0)
 121                return rc;
 122
 123        return 0;
 124}
 125
 126/*
 127 * stk1160_i2c_check_for_device()
 128 * check if there is a i2c_device at the supplied address
 129 */
 130static int stk1160_i2c_check_for_device(struct stk1160 *dev,
 131                unsigned char addr)
 132{
 133        int rc;
 134
 135        /* Set serial device address */
 136        rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
 137        if (rc < 0)
 138                return rc;
 139
 140        /* Set device sub-address, we'll chip version reg */
 141        rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, 0x00);
 142        if (rc < 0)
 143                return rc;
 144
 145        /* Start read now */
 146        rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
 147        if (rc < 0)
 148                return rc;
 149
 150        rc = stk1160_i2c_busy_wait(dev, 0x01);
 151        if (rc < 0)
 152                return -ENODEV;
 153
 154        return 0;
 155}
 156
 157/*
 158 * stk1160_i2c_xfer()
 159 * the main i2c transfer function
 160 */
 161static int stk1160_i2c_xfer(struct i2c_adapter *i2c_adap,
 162                           struct i2c_msg msgs[], int num)
 163{
 164        struct stk1160 *dev = i2c_adap->algo_data;
 165        int addr, rc, i;
 166
 167        for (i = 0; i < num; i++) {
 168                addr = msgs[i].addr << 1;
 169                dprintk_i2c("%s: addr=%x", __func__, addr);
 170
 171                if (!msgs[i].len) {
 172                        /* no len: check only for device presence */
 173                        rc = stk1160_i2c_check_for_device(dev, addr);
 174                        if (rc < 0) {
 175                                dprintk_i2c(" no device\n");
 176                                return rc;
 177                        }
 178
 179                } else if (msgs[i].flags & I2C_M_RD) {
 180                        /* read request without preceding register selection */
 181                        dprintk_i2c(" subaddr not selected");
 182                        rc = -EOPNOTSUPP;
 183                        goto err;
 184
 185                } else if (i + 1 < num && msgs[i].len <= 2 &&
 186                           (msgs[i + 1].flags & I2C_M_RD) &&
 187                           msgs[i].addr == msgs[i + 1].addr) {
 188
 189                        if (msgs[i].len != 1 || msgs[i + 1].len != 1) {
 190                                dprintk_i2c(" len not supported");
 191                                rc = -EOPNOTSUPP;
 192                                goto err;
 193                        }
 194
 195                        dprintk_i2c(" subaddr=%x", msgs[i].buf[0]);
 196
 197                        rc = stk1160_i2c_read_reg(dev, addr, msgs[i].buf[0],
 198                                msgs[i + 1].buf);
 199
 200                        dprintk_i2c(" read=%x", *msgs[i + 1].buf);
 201
 202                        /* consumed two msgs, so we skip one of them */
 203                        i++;
 204
 205                } else {
 206                        if (msgs[i].len != 2) {
 207                                dprintk_i2c(" len not supported");
 208                                rc = -EOPNOTSUPP;
 209                                goto err;
 210                        }
 211
 212                        dprintk_i2c(" subaddr=%x write=%x",
 213                                msgs[i].buf[0],  msgs[i].buf[1]);
 214
 215                        rc = stk1160_i2c_write_reg(dev, addr, msgs[i].buf[0],
 216                                msgs[i].buf[1]);
 217                }
 218
 219                if (rc < 0)
 220                        goto err;
 221                dprintk_i2c(" OK\n");
 222        }
 223
 224        return num;
 225err:
 226        dprintk_i2c(" ERROR: %d\n", rc);
 227        return num;
 228}
 229
 230/*
 231 * functionality(), what da heck is this?
 232 */
 233static u32 functionality(struct i2c_adapter *adap)
 234{
 235        return I2C_FUNC_SMBUS_EMUL;
 236}
 237
 238static struct i2c_algorithm algo = {
 239        .master_xfer   = stk1160_i2c_xfer,
 240        .functionality = functionality,
 241};
 242
 243static struct i2c_adapter adap_template = {
 244        .owner = THIS_MODULE,
 245        .name = "stk1160",
 246        .algo = &algo,
 247};
 248
 249static struct i2c_client client_template = {
 250        .name = "stk1160 internal",
 251};
 252
 253/*
 254 * stk1160_i2c_register()
 255 * register i2c bus
 256 */
 257int stk1160_i2c_register(struct stk1160 *dev)
 258{
 259        int rc;
 260
 261        dev->i2c_adap = adap_template;
 262        dev->i2c_adap.dev.parent = dev->dev;
 263        strcpy(dev->i2c_adap.name, "stk1160");
 264        dev->i2c_adap.algo_data = dev;
 265
 266        i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
 267
 268        rc = i2c_add_adapter(&dev->i2c_adap);
 269        if (rc < 0) {
 270                stk1160_err("cannot add i2c adapter (%d)\n", rc);
 271                return rc;
 272        }
 273
 274        dev->i2c_client = client_template;
 275        dev->i2c_client.adapter = &dev->i2c_adap;
 276
 277        /* Set i2c clock divider device address */
 278        stk1160_write_reg(dev, STK1160_SICTL_CD,  0x0f);
 279
 280        /* ??? */
 281        stk1160_write_reg(dev, STK1160_ASIC + 3,  0x00);
 282
 283        return 0;
 284}
 285
 286/*
 287 * stk1160_i2c_unregister()
 288 * unregister i2c_bus
 289 */
 290int stk1160_i2c_unregister(struct stk1160 *dev)
 291{
 292        i2c_del_adapter(&dev->i2c_adap);
 293        return 0;
 294}
 295