[PATCH 4.13 015/109] pinctrl/amd: save pin registers over suspend/resume

Greg Kroah-Hartman
2017-09-24T20:40:31Z

From: Daniel Drake <drake@endlessm.com>

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>

---
drivers/pinctrl/pinctrl-amd.c | 75 ++++++++++++++++++++++++++++++++++++++++++
drivers/pinctrl/pinctrl-amd.h | 1
2 files changed, 76 insertions(+)

--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -36,6 +36,7 @@
#include <linux/pinctrl/pinconf.h>
#include <linux/pinctrl/pinconf-generic.h>

+#include "core.h"
#include "pinctrl-utils.h"
#include "pinctrl-amd.h"

@@ -725,6 +726,69 @@ static const struct pinconf_ops amd_pinc
.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),
@@ -764,6 +828,14 @@ static int amd_gpio_probe(struct platfor
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;
@@ -853,6 +925,9 @@ static struct platform_driver amd_gpio_d
.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,
--- a/drivers/pinctrl/pinctrl-amd.h
+++ b/drivers/pinctrl/pinctrl-amd.h
@@ -97,6 +97,7 @@ struct amd_gpio {
unsigned int hwbank_num;
struct resource *res;
struct platform_device *pdev;
+ u32 *saved_regs;
};

/* KERNCZ configuration*/