[PATCH v2] i2c: Clarify behavior of I2C_M_RD flag

[PATCH v2] i2c: Clarify behavior of I2C_M_RD flag

[I Viswanath]

Update the description of I2C_M_RD to clarify that not setting it
signals a write transaction

Signed-off-by: I Viswanath <viswanathiyyappan@gmail.com>
---
 include/uapi/linux/i2c.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h
index aa751389de07..29b149ca4b70 100644
--- a/include/uapi/linux/i2c.h
+++ b/include/uapi/linux/i2c.h
@@ -21,7 +21,8 @@
  *
  * @flags:
  *   Supported by all adapters:
- *   %I2C_M_RD: read data (from slave to master). Guaranteed to be 0x0001!
+ *   %I2C_M_RD: read data (from slave to master). Guaranteed to be 0x0001! If
+ *   not set, the transaction is interpreted as write.
  *
  *   Optional:
  *   %I2C_M_DMA_SAFE: the buffer of this message is DMA safe. Makes sense only
-- 
2.49.0

[PATCH v2] i2c: Clarify behavior of I2C_M_RD flag

[Viswanath]

Update the description of I2C_M_RD to clarify that not setting it
signals a write transaction

Signed-off-by: Viswanath <viswanathiyyappan@gmail.com>
---
 include/uapi/linux/i2c.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h
index aa751389de07..29b149ca4b70 100644
--- a/include/uapi/linux/i2c.h
+++ b/include/uapi/linux/i2c.h
@@ -21,7 +21,8 @@
  *
  * @flags:
  *   Supported by all adapters:
- *   %I2C_M_RD: read data (from slave to master). Guaranteed to be 0x0001!
+ *   %I2C_M_RD: read data (from slave to master). Guaranteed to be 0x0001! If
+ *   not set, the transaction is interpreted as write.
  *
  *   Optional:
  *   %I2C_M_DMA_SAFE: the buffer of this message is DMA safe. Makes sense only
-- 
2.49.0

Re: [PATCH v2] i2c: Clarify behavior of I2C_M_RD flag

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 332 bytes --]

On Sun, May 11, 2025 at 02:57:21AM +0530, Viswanath wrote:
> Update the description of I2C_M_RD to clarify that not setting it
> signals a write transaction

Well, ok, if one is new to I2C this might help understanding.

> Signed-off-by: Viswanath <viswanathiyyappan@gmail.com>

Can you please sign with your full name and resend?


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [PATCH v2] i2c: Clarify behavior of I2C_M_RD flag

[I Viswanath]

Apologies, resending my previous reply with a proper subject line.

Hi Wolfram,

Updated the Signed-off-by line with my full legal name, as requested.

Thanks,
I Viswanath