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
  19 #include <linux/delay.h>
  20 #include <linux/i2c.h>
  21
  22 #include "smiapp.h"
  23 #include "smiapp-regs.h"
  24
  25 static uint32_t float_to_u32_mul_1000000(struct i2c_client *client,
  26                                          uint32_t phloat)
  27 {
  28         int32_t exp;
  29         uint64_t man;
  30
  31         if (phloat >= 0x80000000) {
  32                 dev_err(&client->dev, "this is a negative number\n");
  33                 return 0;
  34         }
  35
  36         if (phloat == 0x7f800000)
  37                 return ~0; /* Inf. */
  38
  39         if ((phloat & 0x7f800000) == 0x7f800000) {
  40                 dev_err(&client->dev, "NaN or other special number\n");
  41                 return 0;
  42         }
  43
  44         /* Valid cases begin here */
  45         if (phloat == 0)
  46                 return 0; /* Valid zero */
  47
  48         if (phloat > 0x4f800000)
  49                 return ~0; /* larger than 4294967295 */
  50
  51         /*
  52          * Unbias exponent (note how phloat is now guaranteed to
  53          * have 0 in the high bit)
  54          */
  55         exp = ((int32_t)phloat >> 23) - 127;
  56
  57         /* Extract mantissa, add missing '1' bit and it's in MHz */
  58         man = ((phloat & 0x7fffff) | 0x800000) * 1000000ULL;
  59
  60         if (exp < 0)
  61                 man >>= -exp;
  62         else
  63                 man <<= exp;
  64
  65         man >>= 23; /* Remove mantissa bias */
  66
  67         return man & 0xffffffff;
  68 }
  69
  70
  71 /*
  72  * Read a 8/16/32-bit i2c register.  The value is returned in 'val'.
  73  * Returns zero if successful, or non-zero otherwise.
  74  */
  75 static int ____smiapp_read(struct smiapp_sensor *sensor, u16 reg,
  76                            u16 len, u32 *val)
  77 {
  78         struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
  79         struct i2c_msg msg;
  80         unsigned char data[4];
  81         u16 offset = reg;
  82         int r;
  83
  84         msg.addr = client->addr;
  85         msg.flags = 0;
  86         msg.len = 2;
  87         msg.buf = data;
  88
  89         /* high byte goes out first */
  90         data[0] = (u8) (offset >> 8);
  91         data[1] = (u8) offset;
  92         r = i2c_transfer(client->adapter, &msg, 1);
  93         if (r != 1) {
  94                 if (r >= 0)
  95                         r = -EBUSY;
  96                 goto err;
  97         }
  98
  99         msg.len = len;
 100         msg.flags = I2C_M_RD;
 101         r = i2c_transfer(client->adapter, &msg, 1);
 102         if (r != 1) {
 103                 if (r >= 0)
 104                         r = -EBUSY;
 105                 goto err;
 106         }
 107
 108         *val = 0;
 109         /* high byte comes first */
 110         switch (len) {
 111         case SMIAPP_REG_32BIT:
 112                 *val = (data[0] << 24) + (data[1] << 16) + (data[2] << 8) +
 113                         data[3];
 114                 break;
 115         case SMIAPP_REG_16BIT:
 116                 *val = (data[0] << 8) + data[1];
 117                 break;
 118         case SMIAPP_REG_8BIT:
 119                 *val = data[0];
 120                 break;
 121         default:
 122                 BUG();
 123         }
 124
 125         return 0;
 126
 127 err:
 128         dev_err(&client->dev, "read from offset 0x%x error %d\n", offset, r);
 129
 130         return r;
 131 }
 132
 133 /* Read a register using 8-bit access only. */
 134 static int ____smiapp_read_8only(struct smiapp_sensor *sensor, u16 reg,
 135                                  u16 len, u32 *val)
 136 {
 137         unsigned int i;
 138         int rval;
 139
 140         *val = 0;
 141
 142         for (i = 0; i < len; i++) {
 143                 u32 val8;
 144
 145                 rval = ____smiapp_read(sensor, reg + i, 1, &val8);
 146                 if (rval < 0)
 147                         return rval;
 148                 *val |= val8 << ((len - i - 1) << 3);
 149         }
 150
 151         return 0;
 152 }
 153
 154 /*
 155  * Read a 8/16/32-bit i2c register.  The value is returned in 'val'.
 156  * Returns zero if successful, or non-zero otherwise.
 157  */
 158 static int __smiapp_read(struct smiapp_sensor *sensor, u32 reg, u32 *val,
 159                          bool only8)
 160 {
 161         struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
 162         u8 len = SMIAPP_REG_WIDTH(reg);
 163         int rval;
 164
 165         if (len != SMIAPP_REG_8BIT && len != SMIAPP_REG_16BIT
 166             && len != SMIAPP_REG_32BIT)
 167                 return -EINVAL;
 168
 169         if (len == SMIAPP_REG_8BIT || !only8)
 170                 rval = ____smiapp_read(sensor, SMIAPP_REG_ADDR(reg), len, val);
 171         else
 172                 rval = ____smiapp_read_8only(sensor, SMIAPP_REG_ADDR(reg), len,
 173                                              val);
 174         if (rval < 0)
 175                 return rval;
 176
 177         if (reg & SMIAPP_REG_FLAG_FLOAT)
 178                 *val = float_to_u32_mul_1000000(client, *val);
 179
 180         return 0;
 181 }
 182
 183 int smiapp_read_no_quirk(struct smiapp_sensor *sensor, u32 reg, u32 *val)
 184 {
 185         return __smiapp_read(
 186                 sensor, reg, val,
 187                 smiapp_needs_quirk(sensor,
 188                                    SMIAPP_QUIRK_FLAG_8BIT_READ_ONLY));
 189 }
 190
 191 static int smiapp_read_quirk(struct smiapp_sensor *sensor, u32 reg, u32 *val,
 192                              bool force8)
 193 {
 194         int rval;
 195
 196         *val = 0;
 197         rval = smiapp_call_quirk(sensor, reg_access, false, &reg, val);
 198         if (rval == -ENOIOCTLCMD)
 199                 return 0;
 200         if (rval < 0)
 201                 return rval;
 202
 203         if (force8)
 204                 return __smiapp_read(sensor, reg, val, true);
 205
 206         return smiapp_read_no_quirk(sensor, reg, val);
 207 }
 208
 209 int smiapp_read(struct smiapp_sensor *sensor, u32 reg, u32 *val)
 210 {
 211         return smiapp_read_quirk(sensor, reg, val, false);
 212 }
 213
 214 int smiapp_read_8only(struct smiapp_sensor *sensor, u32 reg, u32 *val)
 215 {
 216         return smiapp_read_quirk(sensor, reg, val, true);
 217 }
 218
 219 int smiapp_write_no_quirk(struct smiapp_sensor *sensor, u32 reg, u32 val)
 220 {
 221         struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
 222         struct i2c_msg msg;
 223         unsigned char data[6];
 224         unsigned int retries;
 225         u8 flags = SMIAPP_REG_FLAGS(reg);
 226         u8 len = SMIAPP_REG_WIDTH(reg);
 227         u16 offset = SMIAPP_REG_ADDR(reg);
 228         int r;
 229
 230         if ((len != SMIAPP_REG_8BIT && len != SMIAPP_REG_16BIT &&
 231              len != SMIAPP_REG_32BIT) || flags)
 232                 return -EINVAL;
 233
 234         msg.addr = client->addr;
 235         msg.flags = 0; /* Write */
 236         msg.len = 2 + len;
 237         msg.buf = data;
 238
 239         /* high byte goes out first */
 240         data[0] = (u8) (reg >> 8);
 241         data[1] = (u8) (reg & 0xff);
 242
 243         switch (len) {
 244         case SMIAPP_REG_8BIT:
 245                 data[2] = val;
 246                 break;
 247         case SMIAPP_REG_16BIT:
 248                 data[2] = val >> 8;
 249                 data[3] = val;
 250                 break;
 251         case SMIAPP_REG_32BIT:
 252                 data[2] = val >> 24;
 253                 data[3] = val >> 16;
 254                 data[4] = val >> 8;
 255                 data[5] = val;
 256                 break;
 257         default:
 258                 BUG();
 259         }
 260
 261         for (retries = 0; retries < 5; retries++) {
 262                 /*
 263                  * Due to unknown reason sensor stops responding. This
 264                  * loop is a temporaty solution until the root cause
 265                  * is found.
 266                  */
 267                 r = i2c_transfer(client->adapter, &msg, 1);
 268                 if (r == 1) {
 269                         if (retries)
 270                                 dev_err(&client->dev,
 271                                         "sensor i2c stall encountered. "
 272                                         "retries: %d\n", retries);
 273                         return 0;
 274                 }
 275
 276                 usleep_range(2000, 2000);
 277         }
 278
 279         dev_err(&client->dev,
 280                 "wrote 0x%x to offset 0x%x error %d\n", val, offset, r);
 281
 282         return r;
 283 }
 284
 285 /*
 286  * Write to a 8/16-bit register.
 287  * Returns zero if successful, or non-zero otherwise.
 288  */
 289 int smiapp_write(struct smiapp_sensor *sensor, u32 reg, u32 val)
 290 {
 291         int rval;
 292
 293         rval = smiapp_call_quirk(sensor, reg_access, true, &reg, &val);
 294         if (rval == -ENOIOCTLCMD)
 295                 return 0;
 296         if (rval < 0)
 297                 return rval;
 298
 299         return smiapp_write_no_quirk(sensor, reg, val);
 300 }