Re: [PATCH v2 22/22] platform/chrome: cros_ec: Use PM subsystem to manage wakeirq

[Tzung-Bi Shih]

On Wed, Dec 20, 2023 at 04:54:36PM -0700, Mark Hasemeyer wrote:
> The IRQ wake logic was added on an interface basis (lpc, spi, uart) as
> opposed to adding it to cros_ec.c because the i2c subsystem already
> enables the wakirq (if applicable) on our behalf.

The setting flow are all the same.  I think helper functions in cros_ec.c help
to deduplicate the code.

> diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
[...]
> +static const struct dmi_system_id untrusted_fw_irq_wake_capable[] = {
> +	{
> +		.ident = "Brya",
> +		.matches = {
> +			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya")
> +		}
> +	},
> +	{
> +		.ident = "Brask",
> +		.matches = {
> +			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brask")
> +		}
> +	},
> +	{ }
> +}
> +MODULE_DEVICE_TABLE(dmi, untrusted_fw_irq_wake_capable);

Does it really need `MODULE_DEVICE_TABLE`?

> +static bool cros_ec_should_force_irq_wake_capable(void)

Suggestion: either drop "cros_ec_" prefix or use "cros_ec_lpc_" prefix.

> @@ -428,20 +453,36 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
>  	 * Some boards do not have an IRQ allotted for cros_ec_lpc,
>  	 * which makes ENXIO an expected (and safe) scenario.
>  	 */
> -	irq = platform_get_irq_optional(pdev, 0);
> -	if (irq > 0)
> +	irq = platform_get_irq_resource_optional(pdev, 0, &irqres);
> +	if (irq > 0) {
>  		ec_dev->irq = irq;
> -	else if (irq != -ENXIO) {
> +		if (cros_ec_should_force_irq_wake_capable())

Please see suggestion above.

>  	ret = cros_ec_register(ec_dev);
>  	if (ret) {
> -		dev_err(dev, "couldn't register ec_dev (%d)\n", ret);
> +		dev_err_probe(dev, ret, "couldn't register ec_dev (%d)\n", ret);

The change is irrelevant to the series.

> +	if (irq_wake) {
> +		ret = device_init_wakeup(dev, true);
> +		if (ret) {
> +			dev_err_probe(dev, ret, "Failed to init device for wakeup");
> +			return ret;
> +		}
> +		ret = dev_pm_set_wake_irq(dev, irq);
> +		if (ret)
> +			return ret;
> +	}
[...]
> @@ -470,6 +512,8 @@ static void cros_ec_lpc_remove(struct platform_device *pdev)
>  		acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
>  					   cros_ec_lpc_acpi_notify);
>  
> +	dev_pm_clear_wake_irq(dev);
> +	device_init_wakeup(dev, false);

Is it safe to call them anyway regardless of `irq_wake` in cros_ec_lpc_probe()?

> diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
[...]
> -static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
> +static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct spi_device *spi)
>  {
> -	struct device_node *np = dev->of_node;
> +	struct cros_ec_device *ec_dev = spi_get_drvdata(spi);
> +	struct device_node *np = spi->dev.of_node;

struct spi_device *spi = ec_spi->spi; [1]

[1]: https://elixir.bootlin.com/linux/v6.6/source/drivers/platform/chrome/cros_ec_spi.c#L751

> +	if (!np)
> +		return;
> +

The change is an improvement (or rather say it could change behavior).  But
strictly speaking, the change is irrelevant to the series.

> @@ -702,6 +710,11 @@ static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
>  	ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
>  	if (!ret)
>  		ec_spi->end_of_msg_delay = val;
> +
> +	if (ec_dev->irq > 0 && of_property_read_bool(np, "wakeup-source")) {

Or just use `spi->irq`[2].

[2]: https://elixir.bootlin.com/linux/v6.6/source/drivers/platform/chrome/cros_ec_spi.c#L762

They are the same, but does of_property_present() make more sense?

> @@ -768,6 +778,9 @@ static int cros_ec_spi_probe(struct spi_device *spi)
>  			   sizeof(struct ec_response_get_protocol_info);
>  	ec_dev->dout_size = sizeof(struct ec_host_request);
>  
> +	/* Check for any DT properties */
> +	cros_ec_spi_dt_probe(ec_spi, spi);

`spi` is possibly not needed.  See comment above.

> @@ -776,19 +789,31 @@ static int cros_ec_spi_probe(struct spi_device *spi)
>  
>  	err = cros_ec_register(ec_dev);
>  	if (err) {
> -		dev_err(dev, "cannot register EC\n");
> +		dev_err_probe(dev, err, "cannot register EC\n");

The change is irrelevant to the series.

> -	device_init_wakeup(&spi->dev, true);
> +	if (ec_spi->irq_wake) {
> +		err = device_init_wakeup(dev, true);
> +		if (err) {
> +			dev_err_probe(dev, err, "Failed to init device for wakeup\n");
> +			return err;
> +		}
> +		err = dev_pm_set_wake_irq(dev, ec_dev->irq);
> +		if (err)
> +			dev_err_probe(dev, err, "Failed to set irq(%d) for wake\n", ec_dev->irq);

The part is different from what the patch changed in cros_ec_lpc.c.  Better to
be consistent.
- Just return vs. dev_err_probe().
- %i vs. %d.

>  static void cros_ec_spi_remove(struct spi_device *spi)
>  {
>  	struct cros_ec_device *ec_dev = spi_get_drvdata(spi);
> +	struct device *dev = ec_dev->dev;
>  
> +	dev_pm_clear_wake_irq(dev);
> +	device_init_wakeup(dev, false);

Ditto, is it safe to just call them regardless of `ec_spi->irq_wake`?

> diff --git a/drivers/platform/chrome/cros_ec_uart.c b/drivers/platform/chrome/cros_ec_uart.c
[...]
> @@ -301,13 +307,31 @@ static int cros_ec_uart_probe(struct serdev_device *serdev)
>  
>  	serdev_device_set_client_ops(serdev, &cros_ec_uart_client_ops);
>  
> -	return cros_ec_register(ec_dev);
> +	/* Register a new cros_ec device */
> +	ret = cros_ec_register(ec_dev);
> +	if (ret) {
> +		dev_err(dev, "Couldn't register ec_dev (%d)\n", ret);

>From reading the changes above, I thought it would use dev_err_probe().

> +	if (ec_uart->irq_wake) {
> +		ret = device_init_wakeup(dev, true);
> +		if (ret) {
> +			dev_err_probe(dev, ret, "Failed to init device for wakeup");
> +			return ret;
> +		}
> +		ret = dev_pm_set_wake_irq(dev, ec_uart->irq);

Ditto, better to be consistent.

>  static void cros_ec_uart_remove(struct serdev_device *serdev)
>  {
>  	struct cros_ec_device *ec_dev = serdev_device_get_drvdata(serdev);
> +	struct device *dev = ec_dev->dev;
>  
> +	dev_pm_clear_wake_irq(dev);
> +	device_init_wakeup(dev, false);

Ditto, is it safe to just call them regardless of `ec_uart->irq_wake`?