[PATCH] regmap-i2c: add 16 bits register width support

From: AceLan Kao
Date: Thu Apr 23 2020 - 04:59:12 EST


This allows to access data with 16 bits register width
via i2c smbus block functions.

The implementation is inspired by below commit
https://patchwork.ozlabs.org/patch/545292/

Signed-off-by: AceLan Kao <acelan.kao@xxxxxxxxxxxxx>
---
drivers/base/regmap/regmap-i2c.c | 61 ++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)

diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c
index 008f8da69d97..62b95a9212ae 100644
--- a/drivers/base/regmap/regmap-i2c.c
+++ b/drivers/base/regmap/regmap-i2c.c
@@ -246,6 +246,63 @@ static const struct regmap_bus regmap_i2c_smbus_i2c_block = {
.max_raw_write = I2C_SMBUS_BLOCK_MAX,
};

+static int regmap_i2c_smbus_i2c_write_reg16(void *context, const void *data,
+ size_t count)
+{
+ struct device *dev = context;
+ struct i2c_client *i2c = to_i2c_client(dev);
+
+ if (count < 2)
+ return -EINVAL;
+
+ count--;
+ return i2c_smbus_write_i2c_block_data(i2c, ((u8 *)data)[0], count,
+ (u8 *)data + 1);
+}
+
+static int regmap_i2c_smbus_i2c_read_reg16(void *context, const void *reg,
+ size_t reg_size, void *val,
+ size_t val_size)
+{
+ struct device *dev = context;
+ struct i2c_client *i2c = to_i2c_client(dev);
+ int ret, count, len = val_size;
+
+ if (reg_size != 2)
+ return -EINVAL;
+
+ ret = i2c_smbus_write_byte_data(i2c, ((u16 *)reg)[0] & 0xff,
+ ((u16 *)reg)[0] >> 8);
+ if (ret < 0)
+ return ret;
+
+ count = 0;
+ do {
+ /* Current Address Read */
+ ret = i2c_smbus_read_byte(i2c);
+ if (ret < 0)
+ break;
+
+ *((u8 *)val++) = ret;
+ count++;
+ len--;
+ } while (len > 0);
+
+ if (count == val_size)
+ return 0;
+ else if (ret < 0)
+ return ret;
+ else
+ return -EIO;
+}
+
+static const struct regmap_bus regmap_i2c_smbus_i2c_block_reg16 = {
+ .write = regmap_i2c_smbus_i2c_write_reg16,
+ .read = regmap_i2c_smbus_i2c_read_reg16,
+ .max_raw_read = I2C_SMBUS_BLOCK_MAX,
+ .max_raw_write = I2C_SMBUS_BLOCK_MAX,
+};
+
static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
const struct regmap_config *config)
{
@@ -255,6 +312,10 @@ static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_I2C_BLOCK))
return &regmap_i2c_smbus_i2c_block;
+ else if (config->val_bits == 8 && config->reg_bits == 16 &&
+ i2c_check_functionality(i2c->adapter,
+ I2C_FUNC_SMBUS_I2C_BLOCK))
+ return &regmap_i2c_smbus_i2c_block_reg16;
else if (config->val_bits == 16 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_WORD_DATA))
--
2.25.1