drivers/media/i2c/smiapp/smiapp-regs.c

   1 /*
   2  * drivers/media/i2c/smiapp/smiapp-regs.c
   3  *
   4  * Generic driver for SMIA/SMIA++ compliant camera modules
   5  *
   6  * Copyright (C) 2011--2012 Nokia Corporation
   7  * Contact: Sakari Ailus <sakari.ailus@iki.fi>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * version 2 as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  21  * 02110-1301 USA
  22  *
  23  */
  24
  25 #include <linux/delay.h>
  26 #include <linux/i2c.h>
  27
  28 #include "smiapp.h"
  29 #include "smiapp-regs.h"
  30
  31 static uint32_t float_to_u32_mul_1000000(struct i2c_client *client,
  32                                          uint32_t phloat)
  33 {
  34         int32_t exp;
  35         uint64_t man;
  36
  37         if (phloat >= 0x80000000) {
  38                 dev_err(&client->dev, "this is a negative number\n");
  39                 return 0;
  40         }
  41
  42         if (phloat == 0x7f800000)
  43                 return ~0; /* Inf. */
  44
  45         if ((phloat & 0x7f800000) == 0x7f800000) {
  46                 dev_err(&client->dev, "NaN or other special number\n");
  47                 return 0;
  48         }
  49
  50         /* Valid cases begin here */
  51         if (phloat == 0)
  52                 return 0; /* Valid zero */
  53
  54         if (phloat > 0x4f800000)
  55                 return ~0; /* larger than 4294967295 */
  56
  57         /*
  58          * Unbias exponent (note how phloat is now guaranteed to
  59          * have 0 in the high bit)
  60          */
  61         exp = ((int32_t)phloat >> 23) - 127;
  62
  63         /* Extract mantissa, add missing '1' bit and it's in MHz */
  64         man = ((phloat & 0x7fffff) | 0x800000) * 1000000ULL;
  65
  66         if (exp < 0)
  67                 man >>= -exp;
  68         else
  69                 man <<= exp;
  70
  71         man >>= 23; /* Remove mantissa bias */
  72
  73         return man & 0xffffffff;
  74 }
  75
  76
  77 /*
  78  * Read a 8/16/32-bit i2c register.  The value is returned in 'val'.
  79  * Returns zero if successful, or non-zero otherwise.
  80  */
  81 static int ____smiapp_read(struct smiapp_sensor *sensor, u16 reg,
  82                            u16 len, u32 *val)
  83 {
  84         struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
  85         struct i2c_msg msg;
  86         unsigned char data[4];
  87         u16 offset = reg;
  88         int r;
  89
  90         msg.addr = client->addr;
  91         msg.flags = 0;
  92         msg.len = 2;
  93         msg.buf = data;
  94
  95         /* high byte goes out first */
  96         data[0] = (u8) (offset >> 8);
  97         data[1] = (u8) offset;
  98         r = i2c_transfer(client->adapter, &msg, 1);
  99         if (r != 1) {
 100                 if (r >= 0)
 101                         r = -EBUSY;
 102                 goto err;
 103         }
 104
 105         msg.len = len;
 106         msg.flags = I2C_M_RD;
 107         r = i2c_transfer(client->adapter, &msg, 1);
 108         if (r != 1) {
 109                 if (r >= 0)
 110                         r = -EBUSY;
 111                 goto err;
 112         }
 113
 114         *val = 0;
 115         /* high byte comes first */
 116         switch (len) {
 117         case SMIA_REG_32BIT:
 118                 *val = (data[0] << 24) + (data[1] << 16) + (data[2] << 8) +
 119                         data[3];
 120                 break;
 121         case SMIA_REG_16BIT:
 122                 *val = (data[0] << 8) + data[1];
 123                 break;
 124         case SMIA_REG_8BIT:
 125                 *val = data[0];
 126                 break;
 127         default:
 128                 BUG();
 129         }
 130
 131         return 0;
 132
 133 err:
 134         dev_err(&client->dev, "read from offset 0x%x error %d\n", offset, r);
 135
 136         return r;
 137 }
 138
 139 /* Read a register using 8-bit access only. */
 140 static int ____smiapp_read_8only(struct smiapp_sensor *sensor, u16 reg,
 141                                  u16 len, u32 *val)
 142 {
 143         unsigned int i;
 144         int rval;
 145
 146         *val = 0;
 147
 148         for (i = 0; i < len; i++) {
 149                 u32 val8;
 150
 151                 rval = ____smiapp_read(sensor, reg + i, 1, &val8);
 152                 if (rval < 0)
 153                         return rval;
 154                 *val |= val8 << ((len - i - 1) << 3);
 155         }
 156
 157         return 0;
 158 }
 159
 160 /*
 161  * Read a 8/16/32-bit i2c register.  The value is returned in 'val'.
 162  * Returns zero if successful, or non-zero otherwise.
 163  */
 164 static int __smiapp_read(struct smiapp_sensor *sensor, u32 reg, u32 *val,
 165                          bool only8)
 166 {
 167         struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
 168         unsigned int len = (u8)(reg >> 16);
 169         int rval;
 170
 171         if (len != SMIA_REG_8BIT && len != SMIA_REG_16BIT
 172             && len != SMIA_REG_32BIT)
 173                 return -EINVAL;
 174
 175         if (smiapp_quirk_reg(sensor, reg, val))
 176                 goto found_quirk;
 177
 178         if (len == SMIA_REG_8BIT && !only8)
 179                 rval = ____smiapp_read(sensor, (u16)reg, len, val);
 180         else
 181                 rval = ____smiapp_read_8only(sensor, (u16)reg, len, val);
 182         if (rval < 0)
 183                 return rval;
 184
 185 found_quirk:
 186         if (reg & SMIA_REG_FLAG_FLOAT)
 187                 *val = float_to_u32_mul_1000000(client, *val);
 188
 189         return 0;
 190 }
 191
 192 int smiapp_read(struct smiapp_sensor *sensor, u32 reg, u32 *val)
 193 {
 194         return __smiapp_read(
 195                 sensor, reg, val,
 196                 smiapp_needs_quirk(sensor,
 197                                    SMIAPP_QUIRK_FLAG_8BIT_READ_ONLY));
 198 }
 199
 200 int smiapp_read_8only(struct smiapp_sensor *sensor, u32 reg, u32 *val)
 201 {
 202         return __smiapp_read(sensor, reg, val, true);
 203 }
 204
 205 /*
 206  * Write to a 8/16-bit register.
 207  * Returns zero if successful, or non-zero otherwise.
 208  */
 209 int smiapp_write(struct smiapp_sensor *sensor, u32 reg, u32 val)
 210 {
 211         struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
 212         struct i2c_msg msg;
 213         unsigned char data[6];
 214         unsigned int retries;
 215         unsigned int flags = reg >> 24;
 216         unsigned int len = (u8)(reg >> 16);
 217         u16 offset = reg;
 218         int r;
 219
 220         if ((len != SMIA_REG_8BIT && len != SMIA_REG_16BIT &&
 221              len != SMIA_REG_32BIT) || flags)
 222                 return -EINVAL;
 223
 224         msg.addr = client->addr;
 225         msg.flags = 0; /* Write */
 226         msg.len = 2 + len;
 227         msg.buf = data;
 228
 229         /* high byte goes out first */
 230         data[0] = (u8) (reg >> 8);
 231         data[1] = (u8) (reg & 0xff);
 232
 233         switch (len) {
 234         case SMIA_REG_8BIT:
 235                 data[2] = val;
 236                 break;
 237         case SMIA_REG_16BIT:
 238                 data[2] = val >> 8;
 239                 data[3] = val;
 240                 break;
 241         case SMIA_REG_32BIT:
 242                 data[2] = val >> 24;
 243                 data[3] = val >> 16;
 244                 data[4] = val >> 8;
 245                 data[5] = val;
 246                 break;
 247         default:
 248                 BUG();
 249         }
 250
 251         for (retries = 0; retries < 5; retries++) {
 252                 /*
 253                  * Due to unknown reason sensor stops responding. This
 254                  * loop is a temporaty solution until the root cause
 255                  * is found.
 256                  */
 257                 r = i2c_transfer(client->adapter, &msg, 1);
 258                 if (r == 1) {
 259                         if (retries)
 260                                 dev_err(&client->dev,
 261                                         "sensor i2c stall encountered. "
 262                                         "retries: %d\n", retries);
 263                         return 0;
 264                 }
 265
 266                 usleep_range(2000, 2000);
 267         }
 268
 269         dev_err(&client->dev,
 270                 "wrote 0x%x to offset 0x%x error %d\n", val, offset, r);
 271
 272         return r;
 273 }