This allows to access data with 16-bit width of registers
via i2c SMBus block functions.
The multi-command sequence of the reading function is not safe
and may read the wrong data from other address if other commands
are sent in-between the SMBus commands in the read function.
Read performance:
32768 bytes (33 kB, 32 KiB) copied, 11.4869 s, 2.9 kB/s
Write performance(with 1-byte page):
32768 bytes (33 kB, 32 KiB) copied, 129.591 s, 0.3 kB/s
The implementation is inspired by below commit
https://patchwork.ozlabs.org/patch/545292/
v2: add more descriptions about the issue that maybe introduced
by this commit
Signed-off-by: AceLan Kao <[email protected]>
---
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 ®map_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 ®map_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
On Fri, 24 Apr 2020 20:33:58 +0800, AceLan Kao wrote:
> This allows to access data with 16-bit width of registers
> via i2c SMBus block functions.
>
> The multi-command sequence of the reading function is not safe
> and may read the wrong data from other address if other commands
> are sent in-between the SMBus commands in the read function.
>
> [...]
Applied to
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git for-5.8
Thanks!
[1/1] regmap-i2c: add 16-bit width registers support
commit: 82f25bd73c0bee4d29df47007a4f7290695b7db7
All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying
to this mail.
Thanks,
Mark