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Commit a2797bea authored by Jon Hunter's avatar Jon Hunter Committed by Linus Walleij
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gpio/omap: force restore if context loss is not detectable 



When booting with device-tree the function pointer for detecting context
loss is not populated. Ideally, the pm_runtime framework should be
enhanced to allow a means for reporting context/state loss and we could
avoid populating such function pointers altogether. In the interim until
a generic non-device specific solution is in place, force a restore of
the gpio bank when enabling the gpio controller.

Adds a new device-tree property for the OMAP GPIO controller to indicate
if the GPIO controller is located in a power-domain that never loses
power and hence will always maintain its logic state.

Signed-off-by: default avatarJon Hunter <jon-hunter@ti.com>
Acked-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: default avatarKevin Hilman <khilman@linaro.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 3513cdec

Documentation/devicetree/bindings/gpio/gpio-omap.txt

+5 −2
Original line number Diff line number Diff line
@@ -21,7 +21,10 @@ Required properties: 


OMAP specific properties:

- ti,hwmods:		Name of the hwmod associated to the GPIO:

  "gpio<X>", <X> being the 1-based instance number from the HW spec

			"gpio<X>", <X> being the 1-based instance number

			from the HW spec.

- ti,gpio-always-on: 	Indicates if a GPIO bank is always powered and

			so will never lose its logic state.





Example:

drivers/gpio/gpio-omap.c

+17 −8
Original line number Diff line number Diff line
@@ -1120,11 +1120,17 @@ static int omap_gpio_probe(struct platform_device *pdev) 
	bank->width = pdata->bank_width;

	bank->is_mpuio = pdata->is_mpuio;

	bank->non_wakeup_gpios = pdata->non_wakeup_gpios;

	bank->loses_context = pdata->loses_context;

	bank->regs = pdata->regs;

#ifdef CONFIG_OF_GPIO

	bank->chip.of_node = of_node_get(node);

#endif

	if (node) {

		if (!of_property_read_bool(node, "ti,gpio-always-on"))

			bank->loses_context = true;

	} else {

		bank->loses_context = pdata->loses_context;

	}





	bank->domain = irq_domain_add_linear(node, bank->width,

					     &irq_domain_simple_ops, NULL);
@@ -1258,9 +1264,9 @@ static int omap_gpio_runtime_resume(struct device *dev) 
{

	struct platform_device *pdev = to_platform_device(dev);

	struct gpio_bank *bank = platform_get_drvdata(pdev);

	int context_lost_cnt_after;

	u32 l = 0, gen, gen0, gen1;

	unsigned long flags;

	int c;



	spin_lock_irqsave(&bank->lock, flags);

	_gpio_dbck_enable(bank);
@@ -1276,16 +1282,19 @@ static int omap_gpio_runtime_resume(struct device *dev) 
	__raw_writel(bank->context.risingdetect,

		     bank->base + bank->regs->risingdetect);



	if (bank->get_context_loss_count) {

		context_lost_cnt_after =

			bank->get_context_loss_count(bank->dev);

		if (context_lost_cnt_after != bank->context_loss_count) {

	if (bank->loses_context) {

		if (!bank->get_context_loss_count) {

			omap_gpio_restore_context(bank);

		} else {

			c = bank->get_context_loss_count(bank->dev);

			if (c != bank->context_loss_count) {

				omap_gpio_restore_context(bank);

			} else {

				spin_unlock_irqrestore(&bank->lock, flags);

				return 0;

			}

		}

	}



	if (!bank->workaround_enabled) {

		spin_unlock_irqrestore(&bank->lock, flags);