drivers/media/pci/mgb4/mgb4_i2c.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2021-2023 Digiteq Automotive
   4  *     author: Martin Tuma <[email protected]>
   5  *
   6  * The i2c module unifies the I2C access to the serializes/deserializes. The I2C
   7  * chips on the GMSL module use 16b addressing, the FPDL3 chips use standard
   8  * 8b addressing.
   9  */
  10
  11 #include "mgb4_i2c.h"
  12
  13 static int read_r16(struct i2c_client *client, u16 reg, u8 *val, int len)
  14 {
  15         int ret;
  16         u8 buf[2];
  17         struct i2c_msg msg[2] = {
  18                 {
  19                         .addr = client->addr,
  20                         .flags = 0,
  21                         .len = 2,
  22                         .buf = buf,
  23                 }, {
  24                         .addr = client->addr,
  25                         .flags = I2C_M_RD,
  26                         .len = len,
  27                         .buf = val,
  28                 }
  29         };
  30
  31         buf[0] = (reg >> 8) & 0xff;
  32         buf[1] = (reg >> 0) & 0xff;
  33
  34         ret = i2c_transfer(client->adapter, msg, 2);
  35         if (ret < 0)
  36                 return ret;
  37         else if (ret != 2)
  38                 return -EREMOTEIO;
  39         else
  40                 return 0;
  41 }
  42
  43 static int write_r16(struct i2c_client *client, u16 reg, const u8 *val, int len)
  44 {
  45         int ret;
  46         u8 buf[4];
  47         struct i2c_msg msg[1] = {
  48                 {
  49                         .addr = client->addr,
  50                         .flags = 0,
  51                         .len = 2 + len,
  52                         .buf = buf,
  53                 }
  54         };
  55
  56         if (2 + len > sizeof(buf))
  57                 return -EINVAL;
  58
  59         buf[0] = (reg >> 8) & 0xff;
  60         buf[1] = (reg >> 0) & 0xff;
  61         memcpy(&buf[2], val, len);
  62
  63         ret = i2c_transfer(client->adapter, msg, 1);
  64         if (ret < 0)
  65                 return ret;
  66         else if (ret != 1)
  67                 return -EREMOTEIO;
  68         else
  69                 return 0;
  70 }
  71
  72 int mgb4_i2c_init(struct mgb4_i2c_client *client, struct i2c_adapter *adap,
  73                   struct i2c_board_info const *info, int addr_size)
  74 {
  75         client->client = i2c_new_client_device(adap, info);
  76         if (IS_ERR(client->client))
  77                 return PTR_ERR(client->client);
  78
  79         client->addr_size = addr_size;
  80
  81         return 0;
  82 }
  83
  84 void mgb4_i2c_free(struct mgb4_i2c_client *client)
  85 {
  86         i2c_unregister_device(client->client);
  87 }
  88
  89 s32 mgb4_i2c_read_byte(struct mgb4_i2c_client *client, u16 reg)
  90 {
  91         int ret;
  92         u8 b;
  93
  94         if (client->addr_size == 8)
  95                 return i2c_smbus_read_byte_data(client->client, reg);
  96
  97         ret = read_r16(client->client, reg, &b, 1);
  98         if (ret < 0)
  99                 return ret;
 100
 101         return (s32)b;
 102 }
 103
 104 s32 mgb4_i2c_write_byte(struct mgb4_i2c_client *client, u16 reg, u8 val)
 105 {
 106         if (client->addr_size == 8)
 107                 return i2c_smbus_write_byte_data(client->client, reg, val);
 108         else
 109                 return write_r16(client->client, reg, &val, 1);
 110 }
 111
 112 s32 mgb4_i2c_mask_byte(struct mgb4_i2c_client *client, u16 reg, u8 mask, u8 val)
 113 {
 114         s32 ret;
 115
 116         if (mask != 0xFF) {
 117                 ret = mgb4_i2c_read_byte(client, reg);
 118                 if (ret < 0)
 119                         return ret;
 120                 val |= (u8)ret & ~mask;
 121         }
 122
 123         return mgb4_i2c_write_byte(client, reg, val);
 124 }
 125
 126 int mgb4_i2c_configure(struct mgb4_i2c_client *client,
 127                        const struct mgb4_i2c_kv *values, size_t count)
 128 {
 129         size_t i;
 130         s32 res;
 131
 132         for (i = 0; i < count; i++) {
 133                 res = mgb4_i2c_mask_byte(client, values[i].reg, values[i].mask,
 134                                          values[i].val);
 135                 if (res < 0)
 136                         return res;
 137         }
 138
 139         return 0;
 140 }