[RFC 07/11] gpio: tegra186: Add HTE in gpio-tegra186 driver

@@ -127,6 +127,12 @@ Required properties:
             - 8: Active low level-sensitive.
             Valid combinations are 1, 2, 3, 4, 8.
 
+Optional properties:
+- timestamp-engine
+    AON GPIO controller has timestamp engine which can hardware timestamp
+    GPIO configured as input and IRQ. This property specifies hardware
+    timestamp engine (HTE) device-tree node.
+
 Example:
 
 #include <dt-bindings/interrupt-controller/irq.h>

@@ -162,4 +168,5 @@ gpio@c2f0000 {
 	#gpio-cells = <2>;
 	interrupt-controller;
 	#interrupt-cells = <2>;
+	timestamp-engine = <&tegra_hte_aon>;
 };

@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/hte.h>
 
 #include <dt-bindings/gpio/tegra186-gpio.h>
 #include <dt-bindings/gpio/tegra194-gpio.h>

@@ -34,6 +35,7 @@
 #define  TEGRA186_GPIO_ENABLE_CONFIG_TRIGGER_LEVEL BIT(4)
 #define  TEGRA186_GPIO_ENABLE_CONFIG_DEBOUNCE BIT(5)
 #define  TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT BIT(6)
+#define  TEGRA186_GPIO_ENABLE_CONFIG_TIMESTAMP_FUNC BIT(7)
 
 #define TEGRA186_GPIO_DEBOUNCE_CONTROL 0x04
 #define  TEGRA186_GPIO_DEBOUNCE_CONTROL_THRESHOLD(x) ((x) & 0xff)

@@ -79,6 +81,7 @@ struct tegra_gpio {
 	struct irq_chip intc;
 	unsigned int num_irq;
 	unsigned int *irq;
+	struct device_node *hte_nd;
 
 	const struct tegra_gpio_soc *soc;
 

@@ -188,6 +191,65 @@ static int tegra186_gpio_direction_output(struct gpio_chip *chip,
 	return 0;
 }
 
+static int tegra186_gpio_timestamp_control(struct gpio_chip *chip,
+					   unsigned int offset,
+					   struct hte_ts_desc **hdesc,
+					   bool enable)
+{
+	struct tegra_gpio *gpio = gpiochip_get_data(chip);
+	void __iomem *base;
+	int value;
+	struct hte_ts_desc *desc;
+
+	if (!gpio->hte_nd)
+		return -ENOTSUPP;
+
+	base = tegra186_gpio_get_base(gpio, offset);
+	if (WARN_ON(base == NULL))
+		return -EINVAL;
+
+	value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG);
+
+	if (enable) {
+		desc = hte_req_ts_by_dt_node(gpio->hte_nd, offset, NULL);
+		if (IS_ERR(desc))
+			return PTR_ERR(desc);
+
+		*hdesc = desc;
+		value |= TEGRA186_GPIO_ENABLE_CONFIG_TIMESTAMP_FUNC;
+	} else {
+		desc = *hdesc;
+		hte_release_ts(desc);
+		value &= ~TEGRA186_GPIO_ENABLE_CONFIG_TIMESTAMP_FUNC;
+	}
+
+	writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG);
+	return 0;
+}
+
+static int tegra186_gpio_get_hw_timestamp(struct gpio_chip *chip, bool block,
+					  struct hte_ts_desc *hdesc, u64 *ts)
+{
+	struct hte_ts_data el;
+	int ret;
+
+	if (!hdesc || !ts)
+		return -EINVAL;
+
+	if (!block)
+		ret = hte_retrieve_ts_ns(hdesc, &el, 1);
+	else
+		/* Wait till timestamp is available */
+		ret = hte_retrieve_ts_ns_wait(hdesc, &el, 1);
+
+	if (ret)
+		return ret;
+
+	*ts = el.tsc;
+
+	return 0;
+}
+
 static int tegra186_gpio_get(struct gpio_chip *chip, unsigned int offset)
 {
 	struct tegra_gpio *gpio = gpiochip_get_data(chip);

@@ -605,6 +667,7 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	struct device_node *np;
 	char **names;
 	int err;
+	phandle hte_ph;
 
 	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
 	if (!gpio)

@@ -730,6 +793,21 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 		offset += port->pins;
 	}
 
+	err = of_property_read_u32(gpio->gpio.of_node,
+				   "timestamp-engine", &hte_ph);
+	if (!err) {
+		gpio->hte_nd = of_find_node_by_phandle(hte_ph);
+		if (!gpio->hte_nd)
+			return -ENOSYS;
+
+		gpio->gpio.timestamp_control = tegra186_gpio_timestamp_control;
+		gpio->gpio.get_hw_timestamp = tegra186_gpio_get_hw_timestamp;
+
+		of_node_put(gpio->hte_nd);
+	} else {
+		gpio->hte_nd = NULL;
+	}
+
 	platform_set_drvdata(pdev, gpio);
 
 	err = devm_gpiochip_add_data(&pdev->dev, &gpio->gpio, gpio);