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: Jon Hunter <jon-hunter@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/devicetree/bindings/gpio/gpio-omap.txt b/Documentation/devicetree/bindings/gpio/gpio-omap.txt
index bff51a2..1b524c0 100644 (file)
--- a/Documentation/devicetree/bindings/gpio/gpio-omap.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-omap.txt
@@ -20,8 +20,11 @@ Required properties:
       8 = active low level-sensitive.
 
 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
+- ti,hwmods:           Name of the hwmod associated to the GPIO:
+                       "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:

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index f46b600..bb1e54f 100644 (file)
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -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);
@@ -1276,14 +1282,17 @@ 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 {
-                       spin_unlock_irqrestore(&bank->lock, flags);
-                       return 0;
+                       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;
+                       }
                }
        }