drivers/media/v4l2-core/v4l2-cci.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MIPI Camera Control Interface (CCI) register access helpers.
   4  *
   5  * Copyright (C) 2023 Hans de Goede <hansg@kernel.org>
   6  */
   7
   8 #include <linux/bitfield.h>
   9 #include <linux/delay.h>
  10 #include <linux/dev_printk.h>
  11 #include <linux/module.h>
  12 #include <linux/regmap.h>
  13 #include <linux/types.h>
  14
  15 #include <linux/unaligned.h>
  16
  17 #include <media/v4l2-cci.h>
  18
  19 int cci_read(struct regmap *map, u32 reg, u64 *val, int *err)
  20 {
  21         bool little_endian;
  22         unsigned int len;
  23         u8 buf[8];
  24         int ret;
  25
  26         /*
  27          * TODO: Fix smatch. Assign *val to 0 here in order to avoid
  28          * failing a smatch check on caller when the caller proceeds to
  29          * read *val without initialising it on caller's side. *val is set
  30          * to a valid value whenever this function returns 0 but smatch
  31          * can't figure that out currently.
  32          */
  33         *val = 0;
  34
  35         if (err && *err)
  36                 return *err;
  37
  38         little_endian = reg & CCI_REG_LE;
  39         len = CCI_REG_WIDTH_BYTES(reg);
  40         reg = CCI_REG_ADDR(reg);
  41
  42         ret = regmap_bulk_read(map, reg, buf, len);
  43         if (ret) {
  44                 dev_err(regmap_get_device(map), "Error reading reg 0x%04x: %d\n",
  45                         reg, ret);
  46                 goto out;
  47         }
  48
  49         switch (len) {
  50         case 1:
  51                 *val = buf[0];
  52                 break;
  53         case 2:
  54                 if (little_endian)
  55                         *val = get_unaligned_le16(buf);
  56                 else
  57                         *val = get_unaligned_be16(buf);
  58                 break;
  59         case 3:
  60                 if (little_endian)
  61                         *val = get_unaligned_le24(buf);
  62                 else
  63                         *val = get_unaligned_be24(buf);
  64                 break;
  65         case 4:
  66                 if (little_endian)
  67                         *val = get_unaligned_le32(buf);
  68                 else
  69                         *val = get_unaligned_be32(buf);
  70                 break;
  71         case 8:
  72                 if (little_endian)
  73                         *val = get_unaligned_le64(buf);
  74                 else
  75                         *val = get_unaligned_be64(buf);
  76                 break;
  77         default:
  78                 dev_err(regmap_get_device(map), "Error invalid reg-width %u for reg 0x%04x\n",
  79                         len, reg);
  80                 ret = -EINVAL;
  81                 break;
  82         }
  83
  84 out:
  85         if (ret && err)
  86                 *err = ret;
  87
  88         return ret;
  89 }
  90 EXPORT_SYMBOL_GPL(cci_read);
  91
  92 int cci_write(struct regmap *map, u32 reg, u64 val, int *err)
  93 {
  94         bool little_endian;
  95         unsigned int len;
  96         u8 buf[8];
  97         int ret;
  98
  99         if (err && *err)
 100                 return *err;
 101
 102         little_endian = reg & CCI_REG_LE;
 103         len = CCI_REG_WIDTH_BYTES(reg);
 104         reg = CCI_REG_ADDR(reg);
 105
 106         switch (len) {
 107         case 1:
 108                 buf[0] = val;
 109                 break;
 110         case 2:
 111                 if (little_endian)
 112                         put_unaligned_le16(val, buf);
 113                 else
 114                         put_unaligned_be16(val, buf);
 115                 break;
 116         case 3:
 117                 if (little_endian)
 118                         put_unaligned_le24(val, buf);
 119                 else
 120                         put_unaligned_be24(val, buf);
 121                 break;
 122         case 4:
 123                 if (little_endian)
 124                         put_unaligned_le32(val, buf);
 125                 else
 126                         put_unaligned_be32(val, buf);
 127                 break;
 128         case 8:
 129                 if (little_endian)
 130                         put_unaligned_le64(val, buf);
 131                 else
 132                         put_unaligned_be64(val, buf);
 133                 break;
 134         default:
 135                 dev_err(regmap_get_device(map), "Error invalid reg-width %u for reg 0x%04x\n",
 136                         len, reg);
 137                 ret = -EINVAL;
 138                 goto out;
 139         }
 140
 141         ret = regmap_bulk_write(map, reg, buf, len);
 142         if (ret)
 143                 dev_err(regmap_get_device(map), "Error writing reg 0x%04x: %d\n",
 144                         reg, ret);
 145
 146 out:
 147         if (ret && err)
 148                 *err = ret;
 149
 150         return ret;
 151 }
 152 EXPORT_SYMBOL_GPL(cci_write);
 153
 154 int cci_update_bits(struct regmap *map, u32 reg, u64 mask, u64 val, int *err)
 155 {
 156         u64 readval;
 157         int ret;
 158
 159         ret = cci_read(map, reg, &readval, err);
 160         if (ret)
 161                 return ret;
 162
 163         val = (readval & ~mask) | (val & mask);
 164
 165         return cci_write(map, reg, val, err);
 166 }
 167 EXPORT_SYMBOL_GPL(cci_update_bits);
 168
 169 int cci_multi_reg_write(struct regmap *map, const struct cci_reg_sequence *regs,
 170                         unsigned int num_regs, int *err)
 171 {
 172         unsigned int i;
 173         int ret;
 174
 175         for (i = 0; i < num_regs; i++) {
 176                 ret = cci_write(map, regs[i].reg, regs[i].val, err);
 177                 if (ret)
 178                         return ret;
 179         }
 180
 181         return 0;
 182 }
 183 EXPORT_SYMBOL_GPL(cci_multi_reg_write);
 184
 185 #if IS_ENABLED(CONFIG_V4L2_CCI_I2C)
 186 struct regmap *devm_cci_regmap_init_i2c(struct i2c_client *client,
 187                                         int reg_addr_bits)
 188 {
 189         struct regmap_config config = {
 190                 .reg_bits = reg_addr_bits,
 191                 .val_bits = 8,
 192                 .reg_format_endian = REGMAP_ENDIAN_BIG,
 193                 .disable_locking = true,
 194         };
 195
 196         return devm_regmap_init_i2c(client, &config);
 197 }
 198 EXPORT_SYMBOL_GPL(devm_cci_regmap_init_i2c);
 199 #endif
 200
 201 MODULE_LICENSE("GPL");
 202 MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
 203 MODULE_DESCRIPTION("MIPI Camera Control Interface (CCI) support");