eeprom: at24: add regmap-based read function

Add regmap-based read function and instead of using three different
read functions (standard, mac, serial) use just one and factor out the
read offset adjustment for mac and serial to at24_adjust_read_offset.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 5f7d81054c11af98b5ce0c5570652084e9df58c8..57a317b2e9a8f9e5cf4c53db428442ba6f016a4e 100644 (file)
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -75,6 +75,7 @@ struct at24_data {
 
        unsigned write_max;
        unsigned num_addresses;
+       unsigned int offset_adj;
 
        struct nvmem_config nvmem_config;
        struct nvmem_device *nvmem;
@@ -312,6 +313,36 @@ static ssize_t at24_eeprom_read_smbus(struct at24_data *at24, char *buf,
        return -ETIMEDOUT;
 }
 
+static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
+                               unsigned int offset, size_t count)
+{
+       unsigned long timeout, read_time;
+       struct at24_client *at24_client;
+       struct i2c_client *client;
+       struct regmap *regmap;
+       int ret;
+
+       at24_client = at24_translate_offset(at24, &offset);
+       regmap = at24_client->regmap;
+       client = at24_client->client;
+
+       if (count > io_limit)
+               count = io_limit;
+
+       /* adjust offset for mac and serial read ops */
+       offset += at24->offset_adj;
+
+       loop_until_timeout(timeout, read_time) {
+               ret = regmap_bulk_read(regmap, offset, buf, count);
+               dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
+                       count, offset, ret, jiffies);
+               if (!ret)
+                       return count;
+       }
+
+       return -ETIMEDOUT;
+}
+
 static ssize_t at24_eeprom_read_i2c(struct at24_data *at24, char *buf,
                                    unsigned int offset, size_t count)
 {
@@ -531,7 +562,7 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
        while (count) {
                int     status;
 
-               status = at24->read_func(at24, buf, off, count);
+               status = at24_regmap_read(at24, buf, off, count);
                if (status < 0) {
                        mutex_unlock(&at24->lock);
                        pm_runtime_put(dev);
@@ -620,6 +651,29 @@ static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
        }
 }
 
+static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len)
+{
+       if (flags & AT24_FLAG_MAC) {
+               /* EUI-48 starts from 0x9a, EUI-64 from 0x98 */
+               return 0xa0 - byte_len;
+       } else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) {
+               /*
+                * For 16 bit address pointers, the word address must contain
+                * a '10' sequence in bits 11 and 10 regardless of the
+                * intended position of the address pointer.
+                */
+               return 0x0800;
+       } else if (flags & AT24_FLAG_SERIAL) {
+               /*
+                * Otherwise the word address must begin with a '10' sequence,
+                * regardless of the intended address.
+                */
+               return 0x0080;
+       } else {
+               return 0;
+       }
+}
+
 static const struct regmap_config regmap_config_8 = {
        .reg_bits = 8,
        .val_bits = 8,
@@ -746,6 +800,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
        at24->use_smbus = use_smbus;
        at24->chip = chip;
        at24->num_addresses = num_addresses;
+       at24->offset_adj = at24_get_offset_adj(chip.flags, chip.byte_len);
 
        at24->client[0].client = client;
        at24->client[0].regmap = devm_regmap_init_i2c(client, config);