Re: [PATCH v7 1/4] Input: stmfts - wait for controller ready after reset

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On September 25, 2026 1:20:56 PM PDT, David Heidelberg <david@ixit.cz> wrote:
>On 25/09/2026 21:27, Dmitry Torokhov wrote:
>> Hi David,
>> 
>> On Mon, Sep 07, 2026 at 12:50:19PM +0200, David Heidelberg via B4 Relay wrote:
>>>   -static void stmfts_reset(struct stmfts_data *sdata)
>>> +static int stmfts_reset(struct stmfts_data *sdata)
>>>   {
>>>   	gpiod_set_value_cansleep(sdata->reset_gpio, 1);
>>>   	msleep(20);
>>>   +	reinit_completion(&sdata->cmd_done);
>>>   	gpiod_set_value_cansleep(sdata->reset_gpio, 0);
>>> -	msleep(50);
>>> +	enable_irq(sdata->client->irq);
>>> +
>>> +	if (!wait_for_completion_timeout(&sdata->cmd_done,
>>> +					 msecs_to_jiffies(STMFTS_RESET_TIMEOUT_MS)))
>>> +		return -ETIMEDOUT;
>>> +
>>> +	return 0;
>>>   }
>>>     static int stmfts_configure(struct stmfts_data *sdata)
>>>   {
>>>   	int err;
>>>     	err = stmfts_command(sdata, STMFTS_SYSTEM_RESET);
>>>   	if (err)
>>> @@ -593,42 +602,47 @@ static int stmfts_power_on(struct stmfts_data *sdata)
>>>   		return err;
>>>     	/*
>>>   	 * The datasheet does not specify the power on time, but considering
>>>   	 * that the reset time is < 10ms, I sleep 20ms to be sure
>>>   	 */
>>>   	msleep(20);
>>>   -	if (sdata->reset_gpio)
>>> -		stmfts_reset(sdata);
>>> +	if (sdata->reset_gpio) {
>>> +		err = stmfts_reset(sdata);
>>> +		if (err) {
>>> +			dev_err(&sdata->client->dev,
>>> +				"controller not ready after reset: %d\n", err);
>>> +			goto err_disable_irq;
>>> +		}
>>> +	} else {
>>> +		enable_irq(sdata->client->irq);
>>> +		msleep(50);
>>> +	}
>>>     	err = stmfts_read_system_info(sdata);
>>>   	if (err)
>>> -		goto err_disable_regulators;
>>> -
>>> -	enable_irq(sdata->client->irq);
>>> -
>>> -	msleep(50);
>>> +		goto err_disable_irq;
>> 
>> 
>> I think the logic is becoming quite convoluted here, and factored out
>> stmfts_reset() does not help. How about we make it look like this:
>> 
>> static int stmfts_power_on(struct stmfts_data *sdata)
>> {
>> 	int err;
>> 
>> 	if (sdata->reset_gpio) {
>> 		gpiod_set_value_cansleep(sdata->reset_gpio, 1);
>> 		/* a short delay before powering up */
>> 		usleep_range(1000, 1500);
>> 	}
>> 
>> 	err = regulator_bulk_enable(ARRAY_SIZE(stmfts_supplies),
>> 				    sdata->supplies);
>> 	if (err)
>> 		return err;
>> 
>> 	if (sdata->reset_gpio) {
>> 		reinit_completion(&sdata->cmd_done);
>> 
>> 		/*
>> 		 * The datasheet does not specify the power on time, but
>> 		 * considering that the reset time is < 10ms, sleep for 20ms
>> 		 * to be sure before releasing reset line.
>> 		 */
>> 		msleep(20);
>> 		gpiod_set_value_cansleep(sdata->reset_gpio, 0);
>> 
>> 		enable_irq(sdata->client->irq);
>> 
>> 		if (!wait_for_completion_timeout(&sdata->cmd_done,
>> 						 msecs_to_jiffies(STMFTS_RESET_TIMEOUT_MS))) {
>> 			dev_err(&sdata->client->dev, "controller not ready after reset");
>> 			err = -ETIMEDOUT;
>> 			goto err_disable_irq;
>> 		}
>> 	} else {
>> 		/*
>> 		 * We do not know the real controller state (was it powered
>> 		 * off or reset). Let's hope that this is enough time to
>> 		 * initialize.
>> 		 */
>> 		msleep(70);
>> 
>> 		enable_irq(sdata->client->irq);
>> 	}
>> 
>> 	err = sdata->ops->configure(sdata);
>> 	if (err)
>> 		goto err_disable_irq;
>> 
>> 	/*
>> 	 * At this point no one is using the touchscreen
>> 	 * and I don't really care about the return value
>> 	 */
>> 	(void)i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);
>> 
>> 	return 0;
>> 
>> err_disable_irq:
>> 	disable_irq(sdata->client->irq);
>> 
>> 	regulator_bulk_disable(ARRAY_SIZE(stmfts_supplies), sdata->supplies);
>> 	return err;
>> }
>
>Thanks, it seems to be better (thou would be nicer if we didn't have two branches, but... what we can do).

That's that enable_irq() in the middle... We could have more "ifs" but that also looks ugly. 

>
>I added you as Co-developed-by :)

Thanks but I don't think the change was large enough to warrant it.


-- 
Dmitry