[PATCH v3] Currently if the SoC needs pinctrl to switch the SCL and SDA from the I2C function to GPIO function, the recovery won't work.

[PATCH v3] Currently if the SoC needs pinctrl to switch the SCL and SDA from the I2C function to GPIO function, the recovery won't work.

[Yann Sionneau]

scl-gpio = <>;
sda-gpio = <>;

Are not enough for some SoCs to have a working recovery.
Some need:

scl-gpio = <>;
sda-gpio = <>;
pinctrl-names = "default", "recovery";
pinctrl-0 = <&i2c_pins_hw>;
pinctrl-1 = <&i2c_pins_gpio>;

The driver was not filling rinfo->pinctrl with the device node
pinctrl data which is needed by generic recovery code.

Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
---
V2 -> V3:
* put back 'if (!rinfo->pinctrl)' test since devm_pinctrl_get()
can return NULL if CONFIG_PINCTRL is not set.
* print an error msg when devm_pinctrl_get() returns an error that
is not -EPROBE_DEFER.
* print a dbg msg if devm_pinctrl_get() return NULL. 

V1 -> V2:
* remove the unnecessary 'if (!rinfo->pinctrl)' test
* test if return is -EPROBE_DEFER, in that case, return it.
* Reword the commit message according to review

 drivers/i2c/busses/i2c-designware-master.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index b720fcc5c10a..30b2de829a32 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -17,6 +17,7 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
@@ -855,6 +856,17 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
 		return PTR_ERR(gpio);
 	rinfo->sda_gpiod = gpio;
 
+	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
+	if (IS_ERR(rinfo->pinctrl)) {
+		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
+			return PTR_ERR(rinfo->pinctrl);
+
+		rinfo->pinctrl = NULL;
+		dev_err(dev->dev, "getting pinctrl info failed: bus recovery might not work\n");
+	} else if (!rinfo->pinctrl) {
+		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");
+	}
+
 	rinfo->recover_bus = i2c_generic_scl_recovery;
 	rinfo->prepare_recovery = i2c_dw_prepare_recovery;
 	rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;
-- 
2.17.1

Re: [PATCH v3] Currently if the SoC needs pinctrl to switch the SCL and SDA from the I2C function to GPIO function, the recovery won't work.

[Andy Shevchenko]

On Tue, Aug 22, 2023 at 11:15:55AM +0200, Yann Sionneau wrote:
> scl-gpio = <>;
> sda-gpio = <>;
> 
> Are not enough for some SoCs to have a working recovery.
> Some need:
> 
> scl-gpio = <>;
> sda-gpio = <>;
> pinctrl-names = "default", "recovery";
> pinctrl-0 = <&i2c_pins_hw>;
> pinctrl-1 = <&i2c_pins_gpio>;
> 
> The driver was not filling rinfo->pinctrl with the device node
> pinctrl data which is needed by generic recovery code.

...

> +	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
> +	if (IS_ERR(rinfo->pinctrl)) {
> +		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
> +			return PTR_ERR(rinfo->pinctrl);
> +
> +		rinfo->pinctrl = NULL;
> +		dev_err(dev->dev, "getting pinctrl info failed: bus recovery might not work\n");
> +	} else if (!rinfo->pinctrl) {
> +		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");
> +	}

A bit of bikeshedding, would the below be slightly better?

	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
	if (IS_ERR(rinfo->pinctrl)) {
		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
			return PTR_ERR(rinfo->pinctrl);

		rinfo->pinctrl = NULL;
		dev_err(dev->dev, "getting pinctrl info failed, disabling...\n");
	}
	if (!rinfo->pinctrl)
		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3] Currently if the SoC needs pinctrl to switch the SCL and SDA from the I2C function to GPIO function, the recovery won't work.

[Andy Shevchenko]

On Tue, Aug 22, 2023 at 11:15:55AM +0200, Yann Sionneau wrote:
> scl-gpio = <>;
> sda-gpio = <>;
> 
> Are not enough for some SoCs to have a working recovery.
> Some need:
> 
> scl-gpio = <>;
> sda-gpio = <>;
> pinctrl-names = "default", "recovery";
> pinctrl-0 = <&i2c_pins_hw>;
> pinctrl-1 = <&i2c_pins_gpio>;
> 
> The driver was not filling rinfo->pinctrl with the device node
> pinctrl data which is needed by generic recovery code.

With or without my suggestion, FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3] Currently if the SoC needs pinctrl to switch the SCL and SDA from the I2C function to GPIO function, the recovery won't work.

[Andy Shevchenko]

On Tue, Aug 22, 2023 at 03:02:48PM +0300, Andy Shevchenko wrote:
> On Tue, Aug 22, 2023 at 11:15:55AM +0200, Yann Sionneau wrote:

...

> > +	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
> > +	if (IS_ERR(rinfo->pinctrl)) {
> > +		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
> > +			return PTR_ERR(rinfo->pinctrl);
> > +
> > +		rinfo->pinctrl = NULL;
> > +		dev_err(dev->dev, "getting pinctrl info failed: bus recovery might not work\n");
> > +	} else if (!rinfo->pinctrl) {
> > +		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");
> > +	}
> 
> A bit of bikeshedding, would the below be slightly better?
> 
> 	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
> 	if (IS_ERR(rinfo->pinctrl)) {
> 		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
> 			return PTR_ERR(rinfo->pinctrl);
> 
> 		rinfo->pinctrl = NULL;
> 		dev_err(dev->dev, "getting pinctrl info failed, disabling...\n");
> 	}
> 	if (!rinfo->pinctrl)
> 		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");

On the second thought they are on a different levels... Anyway, up to you,
folks, what to do with that, I gave already my tag.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3] Currently if the SoC needs pinctrl to switch the SCL and SDA from the I2C function to GPIO function, the recovery won't work.

[Yann Sionneau]

Hi,

On 8/22/23 14:02, Andy Shevchenko wrote:
> On Tue, Aug 22, 2023 at 11:15:55AM +0200, Yann Sionneau wrote:
>> scl-gpio = <>;
>> sda-gpio = <>;
>>
>> Are not enough for some SoCs to have a working recovery.
>> Some need:
>>
>> scl-gpio = <>;
>> sda-gpio = <>;
>> pinctrl-names = "default", "recovery";
>> pinctrl-0 = <&i2c_pins_hw>;
>> pinctrl-1 = <&i2c_pins_gpio>;
>>
>> The driver was not filling rinfo->pinctrl with the device node
>> pinctrl data which is needed by generic recovery code.
> ...
>
>> +	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
>> +	if (IS_ERR(rinfo->pinctrl)) {
>> +		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
>> +			return PTR_ERR(rinfo->pinctrl);
>> +
>> +		rinfo->pinctrl = NULL;
>> +		dev_err(dev->dev, "getting pinctrl info failed: bus recovery might not work\n");
>> +	} else if (!rinfo->pinctrl) {
>> +		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");
>> +	}
> A bit of bikeshedding, would the below be slightly better?
>
> 	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
> 	if (IS_ERR(rinfo->pinctrl)) {
> 		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
> 			return PTR_ERR(rinfo->pinctrl);
>
> 		rinfo->pinctrl = NULL;
> 		dev_err(dev->dev, "getting pinctrl info failed, disabling...\n");

I think the dev_err() message change is not very clear because one might 
think that "disabling" means that the i2c adapter is getting disabled.

Maybe we can put "getting pinctrl info failed, disabling recovery..."?

> 	}
> 	if (!rinfo->pinctrl)
> 		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");
>
Ah yes, I like the getting rid of the `else` part. LGTM I'll re-send 
with that.

Regards,

-- 

Yann