[rtc-linux] [PATCH v2] rtc: omap: Support ext_wakeup configuration

[Marcin Niestroj <m.niestroj@grinn-global.com>]

Support configuration of ext_wakeup sources. This patch makes it
possible to enable ext_wakeup (and set it's polarity), depending on
board configuration. AM335x's dedicated PMIC (tps65217) uses ext_wakeup
in SLEEP mode (RTC-only) to notify about power-button presses. Handling
power-button presses enables to recover from RTC-only power states
correctly.

Implementation uses gpiochip to utilize standard bindings. However,
configuration is possible only using device-tree (no runtime changes).

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
---
 Documentation/devicetree/bindings/rtc/rtc-omap.txt |  18 ++-
 drivers/rtc/Kconfig                                |   2 +-
 drivers/rtc/rtc-omap.c                             | 137 ++++++++++++++++++++-
 3 files changed, 154 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/rtc/rtc-omap.txt b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
index bf7d11a..4a7738e 100644
--- a/Documentation/devicetree/bindings/rtc/rtc-omap.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
@@ -18,8 +18,12 @@ Optional properties:
   through pmic_power_en
 - clocks: Any internal or external clocks feeding in to rtc
 - clock-names: Corresponding names of the clocks
+- gpio-controller: Mark as gpio controller when using ext_wakeup
+- #gpio-cells: Should be set to 2
+- ngpios: Number of ext_wakeup sources supported by processor (board)
+- ext-wakeup-gpios: List of ext_wakeup sources to configure
 
-Example:
+Examples:
 
 rtc@1c23000 {
 	compatible = "ti,da830-rtc";
@@ -31,3 +35,15 @@ rtc@1c23000 {
 	clocks = <&clk_32k_rtc>, <&clk_32768_ck>;
 	clock-names = "ext-clk", "int-clk";
 };
+
+rtc: rtc@44e3e000 {
+	compatible = "ti,am3352-rtc", "ti,da830-rtc";
+	reg = <0x44e3e000 0x1000>;
+	interrupts = <75
+		      76>;
+	system-power-controller;
+	gpio-controller;
+	#gpio-cells = <2>;
+	ngpios = <1>;
+	ext-wakeup-gpios = <&rtc 0 GPIO_ACTIVE_LOW>;
+};
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 3e84315..f013346 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1208,7 +1208,7 @@ config RTC_DRV_IMXDI
 
 config RTC_DRV_OMAP
 	tristate "TI OMAP Real Time Clock"
-	depends on ARCH_OMAP || ARCH_DAVINCI || COMPILE_TEST
+	depends on (ARCH_OMAP || ARCH_DAVINCI || COMPILE_TEST) && GPIOLIB
 	help
 	  Say "yes" here to support the on chip real time clock
 	  present on TI OMAP1, AM33xx, DA8xx/OMAP-L13x, AM43xx and DRA7xx.
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index ec2e9c5..56c7155 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -26,6 +26,8 @@
 #include <linux/pm_runtime.h>
 #include <linux/io.h>
 #include <linux/clk.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/consumer.h>
 
 /*
  * The OMAP RTC is a year/month/day/hours/minutes/seconds BCD clock
@@ -114,7 +116,11 @@
 #define OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN	BIT(1)
 
 /* OMAP_RTC_PMIC bit fields: */
-#define OMAP_RTC_PMIC_POWER_EN_EN	BIT(16)
+#define OMAP_RTC_PMIC_POWER_EN_EN		BIT(16)
+#define OMAP_RTC_PMIC_EXT_WAKEUP_EN(x)		(BIT(x))
+#define OMAP_RTC_PMIC_EXT_WAKEUP_POL(x)		(BIT(x) << 4)
+#define OMAP_RTC_PMIC_EXT_WAKEUP_EN_MASK	(0x0F)
+#define OMAP_RTC_PMIC_EXT_WAKEUP_POL_MASK	(0x0F << 4)
 
 /* OMAP_RTC_KICKER values */
 #define	KICK0_VALUE			0x83e70b13
@@ -141,6 +147,7 @@ struct omap_rtc {
 	bool is_pmic_controller;
 	bool has_ext_clk;
 	const struct omap_rtc_device_type *type;
+	struct gpio_chip gpio_chip;
 };
 
 static inline u8 rtc_read(struct omap_rtc *rtc, unsigned int reg)
@@ -183,6 +190,104 @@ static void default_rtc_lock(struct omap_rtc *rtc)
 {
 }
 
+static int omap_rtc_gpio_request(struct gpio_chip *chip,
+				unsigned int offset)
+{
+	struct omap_rtc *rtc = gpiochip_get_data(chip);
+	u32 val;
+
+	rtc->type->unlock(rtc);
+
+	val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);
+	val |= OMAP_RTC_PMIC_EXT_WAKEUP_EN(offset);
+	rtc_writel(rtc, OMAP_RTC_PMIC_REG, val);
+
+	rtc->type->lock(rtc);
+
+	return 0;
+}
+
+static void omap_rtc_gpio_free(struct gpio_chip *chip,
+			unsigned int offset)
+{
+	struct omap_rtc *rtc = gpiochip_get_data(chip);
+	u32 val;
+
+	rtc->type->unlock(rtc);
+
+	val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);
+	val &= ~OMAP_RTC_PMIC_EXT_WAKEUP_EN(offset);
+	rtc_writel(rtc, OMAP_RTC_PMIC_REG, val);
+
+	rtc->type->lock(rtc);
+}
+
+static int omap_rtc_gpio_get_direction(struct gpio_chip *chip,
+				unsigned int offset)
+{
+	return 1; /* Always in */
+}
+
+
+static int omap_rtc_gpio_direction_input(struct gpio_chip *chip,
+					unsigned int offset)
+{
+	return 0;
+}
+
+static int omap_rtc_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	return 0;
+}
+
+/*
+ * Note: This function is called only when setting ext_wakeup polarity
+ * with omap_rtc_gpio_set_polarity
+ */
+static void omap_rtc_gpio_set(struct gpio_chip *chip, unsigned int offset,
+			int value)
+{
+	struct omap_rtc *rtc = gpiochip_get_data(chip);
+	u32 val;
+
+	rtc->type->unlock(rtc);
+
+	val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);
+	if (value)
+		val |= OMAP_RTC_PMIC_EXT_WAKEUP_POL(offset);
+	else
+		val &= ~OMAP_RTC_PMIC_EXT_WAKEUP_POL(offset);
+	rtc_writel(rtc, OMAP_RTC_PMIC_REG, val);
+
+	rtc->type->lock(rtc);
+}
+
+static void omap_rtc_gpio_set_polarity(struct gpio_descs *ext_wakeup)
+{
+	struct gpio_desc *desc;
+	int i;
+
+	for (i = 0; i < ext_wakeup->ndescs; i++) {
+		desc = ext_wakeup->desc[i];
+		gpiod_set_raw_value_cansleep(desc,
+					gpiod_is_active_low(desc));
+	}
+}
+
+static struct gpio_chip template_chip = {
+	.label			= "omap-rtc-gpio",
+	.owner			= THIS_MODULE,
+	.request		= omap_rtc_gpio_request,
+	.free			= omap_rtc_gpio_free,
+	.get_direction		= omap_rtc_gpio_get_direction,
+	.direction_input	= omap_rtc_gpio_direction_input,
+	.get			= omap_rtc_gpio_get,
+	.set			= omap_rtc_gpio_set,
+	.base			= -1,
+	.ngpio			= 4,
+	.can_sleep		= true,
+};
+
 /*
  * We rely on the rtc framework to handle locking (rtc->ops_lock),
  * so the only other requirement is that register accesses which
@@ -533,6 +638,8 @@ static int omap_rtc_probe(struct platform_device *pdev)
 	const struct platform_device_id *id_entry;
 	const struct of_device_id *of_id;
 	int ret;
+	struct gpio_descs *ext_wakeup;
+	u32 ngpios = 0;
 
 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 	if (!rtc)
@@ -544,6 +651,10 @@ static int omap_rtc_probe(struct platform_device *pdev)
 		rtc->is_pmic_controller = rtc->type->has_pmic_mode &&
 				of_property_read_bool(pdev->dev.of_node,
 						"system-power-controller");
+		ret = of_property_read_u32(pdev->dev.of_node, "ngpios",
+					&ngpios);
+		if (ret)
+			ngpios = 0;
 	} else {
 		id_entry = platform_get_device_id(pdev);
 		rtc->type = (void *)id_entry->driver_data;
@@ -577,6 +688,30 @@ static int omap_rtc_probe(struct platform_device *pdev)
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_get_sync(&pdev->dev);
 
+	if (ngpios > 0) {
+		rtc->gpio_chip = template_chip;
+		rtc->gpio_chip.parent = &pdev->dev;
+		rtc->gpio_chip.ngpio = ngpios;
+		ret = devm_gpiochip_add_data(&pdev->dev, &rtc->gpio_chip,
+					rtc);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "Could not register gpiochip, %d\n",
+				ret);
+			return ret;
+		}
+
+		ext_wakeup = devm_gpiod_get_array_optional(&pdev->dev,
+						"ext-wakeup", GPIOD_IN);
+		if (IS_ERR(ext_wakeup)) {
+			ret = PTR_ERR(ext_wakeup);
+			dev_err(&pdev->dev,
+				"ext-wakeup request failed, ret %d\n", ret);
+			return ret;
+		}
+		if (ext_wakeup)
+			omap_rtc_gpio_set_polarity(ext_wakeup);
+	}
+
 	rtc->type->unlock(rtc);
 
 	/*
-- 
2.8.0

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