2023-08-17 17:45:42

by Huangzheng Lai

Subject: [PATCH 2/8] i2c: sprd: Add I2C driver to use 'reset framework' function

This patch adds the 'reset framework' function for I2C drivers, which
resets the I2C controller when a timeout exception occurs.

Signed-off-by: Huangzheng Lai <[email protected]>
---
drivers/i2c/busses/i2c-sprd.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
index acc2a4d4eeae..066b3a9c30c8 100644
--- a/drivers/i2c/busses/i2c-sprd.c
+++ b/drivers/i2c/busses/i2c-sprd.c
@@ -17,6 +17,7 @@
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
+#include <linux/reset.h>

#define I2C_CTL 0x00
#define I2C_ADDR_CFG 0x04
@@ -85,6 +86,7 @@ struct sprd_i2c {
u32 src_clk;
u32 bus_freq;
struct completion complete;
+ struct reset_control *rst;
u8 *buf;
u32 count;
int irq;
@@ -247,6 +249,7 @@ static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
{
struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
unsigned long time_left;
+ int ret;

i2c_dev->msg = msg;
i2c_dev->buf = msg->buf;
@@ -278,9 +281,16 @@ static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,

time_left = wait_for_completion_timeout(&i2c_dev->complete,
msecs_to_jiffies(I2C_XFER_TIMEOUT));
- if (!time_left)
+ if (!time_left) {
+ dev_err(i2c_dev->dev, "transfer timeout, I2C_STATUS = 0x%x\n",
+ readl(i2c_dev->base + I2C_STATUS));
+ if (i2c_dev->rst != NULL) {
+ ret = reset_control_reset(i2c_dev->rst);
+ if (ret < 0)
+ dev_err(i2c_dev->dev, "i2c soft reset failed, ret = %d\n", ret);
+ }
return -ETIMEDOUT;
-
+ }
return i2c_dev->err;
}

@@ -535,6 +545,11 @@ static int sprd_i2c_probe(struct platform_device *pdev)
return ret;

platform_set_drvdata(pdev, i2c_dev);
+ i2c_dev->rst = devm_reset_control_get(i2c_dev->dev, "i2c_rst");
+ if (IS_ERR(i2c_dev->rst)) {
+ dev_err(i2c_dev->dev, "can't get i2c reset node\n");
+ i2c_dev->rst = NULL;
+ }

ret = clk_prepare_enable(i2c_dev->clk);
if (ret)
--
2.17.1

2023-09-04 18:49:18

by Andi Shyti

Subject: Re: [PATCH 2/8] i2c: sprd: Add I2C driver to use 'reset framework' function

Hi Huangzheng,

On Thu, Aug 17, 2023 at 05:45:14PM +0800, Huangzheng Lai wrote:
> This patch adds the 'reset framework' function for I2C drivers, which
> resets the I2C controller when a timeout exception occurs.

as in the earlier patch, please use the imperative form.

> Signed-off-by: Huangzheng Lai <[email protected]>

[...]

> @@ -247,6 +249,7 @@ static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
> {
> struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
> unsigned long time_left;
> + int ret;

please move this declaration...

>
> i2c_dev->msg = msg;
> i2c_dev->buf = msg->buf;
> @@ -278,9 +281,16 @@ static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
>
> time_left = wait_for_completion_timeout(&i2c_dev->complete,
> msecs_to_jiffies(I2C_XFER_TIMEOUT));
> - if (!time_left)
> + if (!time_left) {
> + dev_err(i2c_dev->dev, "transfer timeout, I2C_STATUS = 0x%x\n",
> + readl(i2c_dev->base + I2C_STATUS));
> + if (i2c_dev->rst != NULL) {

... here.

> + ret = reset_control_reset(i2c_dev->rst);
> + if (ret < 0)
> + dev_err(i2c_dev->dev, "i2c soft reset failed, ret = %d\n", ret);

dev_warn()

> + }
> return -ETIMEDOUT;
> -
> + }
> return i2c_dev->err;
> }
>
> @@ -535,6 +545,11 @@ static int sprd_i2c_probe(struct platform_device *pdev)
> return ret;
>
> platform_set_drvdata(pdev, i2c_dev);
> + i2c_dev->rst = devm_reset_control_get(i2c_dev->dev, "i2c_rst");
> + if (IS_ERR(i2c_dev->rst)) {
> + dev_err(i2c_dev->dev, "can't get i2c reset node\n");

if the i2c_rst is optional then this is not an error and it
should use dev_dbg(); right?

In that case please reword the message to "reset control not
configured".

Andi