pinctrl/amd: save pin registers over suspend/resume

commit 79d2c8bede2c93f9432d7da0bc2f76a195c90fc0 upstream.

The touchpad in the Asus laptop models X505BA/BP and X542BA/BP is
unresponsive after suspend/resume. The following error appears during
resume:

  i2c_hid i2c-ELAN1300:00: failed to reset device.

The problem here is that i2c_hid does not notice the interrupt being
generated at this point, because the GPIO is no longer configured
for interrupts.

Fix this by saving pinctrl-amd pin registers during suspend and
restoring them at resume time.

Based on code from pinctrl-intel.

Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index c9a1469..a5b7bd3 100644 (file)
--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -32,6 +32,7 @@
 #include <linux/pinctrl/pinconf.h>
 #include <linux/pinctrl/pinconf-generic.h>
 
+#include "core.h"
 #include "pinctrl-utils.h"
 #include "pinctrl-amd.h"
 
@@ -712,6 +713,69 @@ static const struct pinconf_ops amd_pinconf_ops = {
        .pin_config_group_set = amd_pinconf_group_set,
 };
 
+#ifdef CONFIG_PM_SLEEP
+static bool amd_gpio_should_save(struct amd_gpio *gpio_dev, unsigned int pin)
+{
+       const struct pin_desc *pd = pin_desc_get(gpio_dev->pctrl, pin);
+
+       if (!pd)
+               return false;
+
+       /*
+        * Only restore the pin if it is actually in use by the kernel (or
+        * by userspace).
+        */
+       if (pd->mux_owner || pd->gpio_owner ||
+           gpiochip_line_is_irq(&gpio_dev->gc, pin))
+               return true;
+
+       return false;
+}
+
+int amd_gpio_suspend(struct device *dev)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct amd_gpio *gpio_dev = platform_get_drvdata(pdev);
+       struct pinctrl_desc *desc = gpio_dev->pctrl->desc;
+       int i;
+
+       for (i = 0; i < desc->npins; i++) {
+               int pin = desc->pins[i].number;
+
+               if (!amd_gpio_should_save(gpio_dev, pin))
+                       continue;
+
+               gpio_dev->saved_regs[i] = readl(gpio_dev->base + pin*4);
+       }
+
+       return 0;
+}
+
+int amd_gpio_resume(struct device *dev)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct amd_gpio *gpio_dev = platform_get_drvdata(pdev);
+       struct pinctrl_desc *desc = gpio_dev->pctrl->desc;
+       int i;
+
+       for (i = 0; i < desc->npins; i++) {
+               int pin = desc->pins[i].number;
+
+               if (!amd_gpio_should_save(gpio_dev, pin))
+                       continue;
+
+               writel(gpio_dev->saved_regs[i], gpio_dev->base + pin*4);
+       }
+
+       return 0;
+}
+
+static const struct dev_pm_ops amd_gpio_pm_ops = {
+       SET_LATE_SYSTEM_SLEEP_PM_OPS(amd_gpio_suspend,
+                                    amd_gpio_resume)
+};
+#endif
+
 static struct pinctrl_desc amd_pinctrl_desc = {
        .pins   = kerncz_pins,
        .npins = ARRAY_SIZE(kerncz_pins),
@@ -751,6 +815,14 @@ static int amd_gpio_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
+#ifdef CONFIG_PM_SLEEP
+       gpio_dev->saved_regs = devm_kcalloc(&pdev->dev, amd_pinctrl_desc.npins,
+                                           sizeof(*gpio_dev->saved_regs),
+                                           GFP_KERNEL);
+       if (!gpio_dev->saved_regs)
+               return -ENOMEM;
+#endif
+
        gpio_dev->pdev = pdev;
        gpio_dev->gc.direction_input    = amd_gpio_direction_input;
        gpio_dev->gc.direction_output   = amd_gpio_direction_output;
@@ -839,6 +911,9 @@ static struct platform_driver amd_gpio_driver = {
        .driver         = {
                .name   = "amd_gpio",
                .acpi_match_table = ACPI_PTR(amd_gpio_acpi_match),
+#ifdef CONFIG_PM_SLEEP
+               .pm     = &amd_gpio_pm_ops,
+#endif
        },
        .probe          = amd_gpio_probe,
        .remove         = amd_gpio_remove,

diff --git a/drivers/pinctrl/pinctrl-amd.h b/drivers/pinctrl/pinctrl-amd.h
index 7bfea47..e8bbb20 100644 (file)
--- a/drivers/pinctrl/pinctrl-amd.h
+++ b/drivers/pinctrl/pinctrl-amd.h
@@ -95,6 +95,7 @@ struct amd_gpio {
        struct gpio_chip        gc;
        struct resource         *res;
        struct platform_device  *pdev;
+       u32                     *saved_regs;
 };
 
 /*  KERNCZ configuration*/