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 25static 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 */ 75static 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 127err: 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. */ 134static 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 */ 158static 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 183int 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 191int smiapp_read(struct smiapp_sensor *sensor, u32 reg, u32 *val) 192{ 193 int rval; 194 195 *val = 0; 196 rval = smiapp_call_quirk(sensor, reg_access, false, ®, val); 197 if (rval == -ENOIOCTLCMD) 198 return 0; 199 if (rval < 0) 200 return rval; 201 202 return smiapp_read_no_quirk(sensor, reg, val); 203} 204 205int smiapp_read_8only(struct smiapp_sensor *sensor, u32 reg, u32 *val) 206{ 207 int rval; 208 209 *val = 0; 210 rval = smiapp_call_quirk(sensor, reg_access, false, ®, val); 211 if (rval == -ENOIOCTLCMD) 212 return 0; 213 if (rval < 0) 214 return rval; 215 216 return __smiapp_read(sensor, reg, val, true); 217} 218 219int 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 */ 289int smiapp_write(struct smiapp_sensor *sensor, u32 reg, u32 val) 290{ 291 int rval; 292 293 rval = smiapp_call_quirk(sensor, reg_access, true, ®, &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} 301