gpio/omap: ensure gpio context is initialised

Commit a2797be (gpio/omap: force restore if context loss is not
detectable) broke gpio support for OMAP when booting with device-tree
because a restore of the gpio context being performed without ever
initialising the gpio context. In other words, the context restored was
bad.

This problem could also occur in the non device-tree case, however, it
is much less likely because when booting without device-tree we can
detect context loss via a platform specific API and so context restore
is performed less often.

Nevertheless we should ensure that the gpio context is initialised
on the first pm-runtime resume for gpio banks that could lose their
state regardless of whether we are booting with device-tree or not.

The context loss count was being initialised on the first pm-runtime
suspend following a resume, by populating the get_count_loss_count()
function pointer after the first pm-runtime resume. To make the code
more readable and logical, initialise the context loss count on the
first pm-runtime resume if the context is not yet valid.

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

1 files changed, 45 insertions, 3 deletions

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 2050891d9c65..d3f7d2db870f 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -69,6 +69,7 @@ struct gpio_bank {
         bool is_mpuio;
         bool dbck_flag;
         bool loses_context;
+        bool context_valid;
         int stride;
         u32 width;
         int context_loss_count;
@@ -1128,6 +1129,10 @@ static int omap_gpio_probe(struct platform_device *pdev)
                         bank->loses_context = true;
         } else {
                 bank->loses_context = pdata->loses_context;
+
+                if (bank->loses_context)
+                        bank->get_context_loss_count =
+                                pdata->get_context_loss_count;
         }
 
 
@@ -1178,9 +1183,6 @@ static int omap_gpio_probe(struct platform_device *pdev)
         omap_gpio_chip_init(bank);
         omap_gpio_show_rev(bank);
 
-        if (bank->loses_context)
-                bank->get_context_loss_count = pdata->get_context_loss_count;
-
         pm_runtime_put(bank->dev);
 
         list_add_tail(&bank->node, &omap_gpio_list);
@@ -1259,6 +1261,8 @@ update_gpio_context_count:
         return 0;
 }
 
+static void omap_gpio_init_context(struct gpio_bank *p);
+
 static int omap_gpio_runtime_resume(struct device *dev)
 {
         struct platform_device *pdev = to_platform_device(dev);
@@ -1268,6 +1272,20 @@ static int omap_gpio_runtime_resume(struct device *dev)
         int c;
 
         spin_lock_irqsave(&bank->lock, flags);
+
+        /*
+         * On the first resume during the probe, the context has not
+         * been initialised and so initialise it now. Also initialise
+         * the context loss count.
+         */
+        if (bank->loses_context && !bank->context_valid) {
+                omap_gpio_init_context(bank);
+
+                if (bank->get_context_loss_count)
+                        bank->context_loss_count =
+                                bank->get_context_loss_count(bank->dev);
+        }
+
         _gpio_dbck_enable(bank);
 
         /*
@@ -1384,6 +1402,29 @@ void omap2_gpio_resume_after_idle(void)
 }
 
 #if defined(CONFIG_PM_RUNTIME)
+static void omap_gpio_init_context(struct gpio_bank *p)
+{
+        struct omap_gpio_reg_offs *regs = p->regs;
+        void __iomem *base = p->base;
+
+        p->context.ctrl         = __raw_readl(base + regs->ctrl);
+        p->context.oe           = __raw_readl(base + regs->direction);
+        p->context.wake_en      = __raw_readl(base + regs->wkup_en);
+        p->context.leveldetect0 = __raw_readl(base + regs->leveldetect0);
+        p->context.leveldetect1 = __raw_readl(base + regs->leveldetect1);
+        p->context.risingdetect = __raw_readl(base + regs->risingdetect);
+        p->context.fallingdetect = __raw_readl(base + regs->fallingdetect);
+        p->context.irqenable1   = __raw_readl(base + regs->irqenable);
+        p->context.irqenable2   = __raw_readl(base + regs->irqenable2);
+
+        if (regs->set_dataout && p->regs->clr_dataout)
+                p->context.dataout = __raw_readl(base + regs->set_dataout);
+        else
+                p->context.dataout = __raw_readl(base + regs->dataout);
+
+        p->context_valid = true;
+}
+
 static void omap_gpio_restore_context(struct gpio_bank *bank)
 {
         __raw_writel(bank->context.wake_en,
@@ -1421,6 +1462,7 @@ static void omap_gpio_restore_context(struct gpio_bank *bank)
 #else
 #define omap_gpio_runtime_suspend NULL
 #define omap_gpio_runtime_resume NULL
+static void omap_gpio_init_context(struct gpio_bank *p) {}
 #endif
 
 static const struct dev_pm_ops gpio_pm_ops = {