linux-kernel - [PATCH v3 05/14] i2c-octeon: Make adapter timeout tunable

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Date:	Mon,  7 Mar 2016 16:10:48 +0100
From:	Jan Glauber <jglauber@...ium.com>
To:	Wolfram Sang <wsa@...-dreams.de>
Cc:	linux-kernel@...r.kernel.org, linux-i2c@...r.kernel.org,
	David Daney <ddaney@...iumnetworks.com>,
	Peter Swain <pswain@...ium.com>,
	Jan Glauber <jglauber@...ium.com>
Subject: [PATCH v3 05/14] i2c-octeon: Make adapter timeout tunable

From: Peter Swain <pswain@...ium.com>

Make the i2c adapter timeout a module parameter to allow upper-level
target device drivers to retry with their own logic before their own
timeouts abort operations.

For example, at24 eeprom driver retries for 25ms when -EAGAIN
indicates that an eeprom has gone unresponsive while committing
a newly written page (5ms on typical devices).

Signed-off-by: Peter Swain <pswain@...ium.com>
Signed-off-by: Jan Glauber <jglauber@...ium.com>
---
 drivers/i2c/busses/i2c-octeon.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index 6041cd7..ef1720f 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -72,6 +72,10 @@ struct octeon_i2c {
 	struct device *dev;
 };
 
+static int timeout = 2;
+module_param(timeout, int, 0444);
+MODULE_PARM_DESC(timeout, "Low-level device timeout (ms)");
+
 /**
  * octeon_i2c_write_sw - write an I2C core register
  * @i2c: The struct octeon_i2c
@@ -425,7 +429,6 @@ static struct i2c_adapter octeon_i2c_ops = {
 	.owner = THIS_MODULE,
 	.name = "OCTEON adapter",
 	.algo = &octeon_i2c_algo,
-	.timeout = HZ / 50,
 };
 
 /* calculate and set clock divisors */
@@ -561,6 +564,8 @@ static int octeon_i2c_probe(struct platform_device *pdev)
 	octeon_i2c_setclock(i2c);
 
 	i2c->adap = octeon_i2c_ops;
+	i2c->adap.timeout = msecs_to_jiffies(timeout);
+	i2c->adap.retries = 10;
 	i2c->adap.dev.parent = &pdev->dev;
 	i2c->adap.dev.of_node = node;
 	i2c_set_adapdata(&i2c->adap, i2c);
-- 
1.9.1