diff mbox series

[v2,08/11] i2c: nomadik: fetch i2c-transfer-timeout-us property from devicetree

Message ID 20240229-mbly-i2c-v2-8-b32ed18c098c@bootlin.com
State New
Headers
Series Add Mobileye EyeQ5 support to the Nomadik I2C controller & use hrtimers for timeouts |

Commit Message

Théo Lebrun Feb. 29, 2024, 6:10 p.m. UTC 
  Allow overriding the default timeout value (200ms) from devicetree,
using the generic i2c-transfer-timeout-us property.

The i2c_adapter->timeout field is an unaccurate jiffies amount;
i2c-nomadik uses hrtimers for timeouts below one jiffy.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 drivers/i2c/busses/i2c-nomadik.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Comments

Linus Walleij Feb. 29, 2024, 9:04 p.m. UTC | #1 
On Thu, Feb 29, 2024 at 7:10 PM Théo Lebrun <theo.lebrun@bootlin.com> wrote:

> Allow overriding the default timeout value (200ms) from devicetree,
> using the generic i2c-transfer-timeout-us property.
>
> The i2c_adapter->timeout field is an unaccurate jiffies amount;
> i2c-nomadik uses hrtimers for timeouts below one jiffy.
>
> Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij
Wolfram Sang March 4, 2024, 9:25 a.m. UTC | #2 
On Thu, Feb 29, 2024 at 07:10:56PM +0100, Théo Lebrun wrote:
> Allow overriding the default timeout value (200ms) from devicetree,
> using the generic i2c-transfer-timeout-us property.
> 
> The i2c_adapter->timeout field is an unaccurate jiffies amount;
> i2c-nomadik uses hrtimers for timeouts below one jiffy.
> 
> Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>

I agree to get the DT property here in the driver. We may later refactor
it to handle it in the I2C core. Syncing this new property with the
existing 'adapter->timeout' will be a tad annoying, though. But I guess
the shorter timeouts are a desired feature these days...

Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Andi Shyti March 4, 2024, 1:57 p.m. UTC | #3 
Hi Theo,

On Thu, Feb 29, 2024 at 07:10:56PM +0100, Théo Lebrun wrote:
> Allow overriding the default timeout value (200ms) from devicetree,
> using the generic i2c-transfer-timeout-us property.
> 
> The i2c_adapter->timeout field is an unaccurate jiffies amount;
> i2c-nomadik uses hrtimers for timeouts below one jiffy.
> 
> Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

Thanks,
Andi
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index afd54999bbbb..2d3247979e45 100644
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -964,6 +964,8 @@  static const struct i2c_algorithm nmk_i2c_algo = {
 static void nmk_i2c_of_probe(struct device_node *np,
 			     struct nmk_i2c_dev *priv)
 {
+	u32 timeout_usecs;
+
 	/* Default to 100 kHz if no frequency is given in the node */
 	if (of_property_read_u32(np, "clock-frequency", &priv->clk_freq))
 		priv->clk_freq = I2C_MAX_STANDARD_MODE_FREQ;
@@ -975,7 +977,12 @@  static void nmk_i2c_of_probe(struct device_node *np,
 		priv->sm = I2C_FREQ_MODE_FAST;
 	priv->tft = 1; /* Tx FIFO threshold */
 	priv->rft = 8; /* Rx FIFO threshold */
-	priv->timeout_usecs = 200 * USEC_PER_MSEC; /* Slave response timeout */
+
+	/* Slave response timeout */
+	if (!of_property_read_u32(np, "i2c-transfer-timeout-us", &timeout_usecs))
+		priv->timeout_usecs = timeout_usecs;
+	else
+		priv->timeout_usecs = 200 * USEC_PER_MSEC;
 }
 
 static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)