phy-sun4i-usb: Add id and vbus detection support for the otg phy (phy0)

The usb0 phy is connected to an OTG controller, and as such needs some special
handling:

1) It allows explicit control over the pullups, enable these on phy_init and
disable them on phy_exit.

2) It has bits to signal id and vbus detect to the musb-core, add support for
for monitoring id and vbus detect gpio-s for use in dual role mode, and set
these bits to the correct values for operating in host only mode when no
gpios are specified in the devicetree.

While updating the devicetree binding documentation also add documentation
for the sofar undocumented usage of regulators for vbus for all 3 phys.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

1 files changed, 240 insertions, 10 deletions

diff --git a/drivers/phy/phy-sun4i-usb.c b/drivers/phy/phy-sun4i-usb.c
index e17c539e4f6f..37f52f73fdba 100644
--- a/drivers/phy/phy-sun4i-usb.c
+++ b/drivers/phy/phy-sun4i-usb.c
@@ -1,7 +1,7 @@
 /*
  * Allwinner sun4i USB phy driver
  *
- * Copyright (C) 2014 Hans de Goede <hdegoede@redhat.com>
+ * Copyright (C) 2014-2015 Hans de Goede <hdegoede@redhat.com>
  *
  * Based on code from
  * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
@@ -24,16 +24,19 @@
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
+#include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/of_gpio.h>
 #include <linux/phy/phy.h>
 #include <linux/phy/phy-sun4i-usb.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 #include <linux/reset.h>
+#include <linux/workqueue.h>
 
 #define REG_ISCR			0x00
 #define REG_PHYCTL			0x04
@@ -47,6 +50,17 @@
 #define SUNXI_AHB_INCRX_ALIGN_EN	BIT(8)
 #define SUNXI_ULPI_BYPASS_EN		BIT(0)
 
+/* ISCR, Interface Status and Control bits */
+#define ISCR_ID_PULLUP_EN		(1 << 17)
+#define ISCR_DPDM_PULLUP_EN	(1 << 16)
+/* sunxi has the phy id/vbus pins not connected, so we use the force bits */
+#define ISCR_FORCE_ID_MASK	(3 << 14)
+#define ISCR_FORCE_ID_LOW		(2 << 14)
+#define ISCR_FORCE_ID_HIGH	(3 << 14)
+#define ISCR_FORCE_VBUS_MASK	(3 << 12)
+#define ISCR_FORCE_VBUS_LOW	(2 << 12)
+#define ISCR_FORCE_VBUS_HIGH	(3 << 12)
+
 /* Common Control Bits for Both PHYs */
 #define PHY_PLL_BW			0x03
 #define PHY_RES45_CAL_EN		0x0c
@@ -63,6 +77,13 @@
 
 #define MAX_PHYS			3
 
+/*
+ * Note do not raise the debounce time, we must report Vusb high within 100ms
+ * otherwise we get Vbus errors
+ */
+#define DEBOUNCE_TIME			msecs_to_jiffies(50)
+#define POLL_TIME			msecs_to_jiffies(250)
+
 struct sun4i_usb_phy_data {
 	void __iomem *base;
 	struct mutex mutex;
@@ -74,13 +95,56 @@ struct sun4i_usb_phy_data {
 		struct regulator *vbus;
 		struct reset_control *reset;
 		struct clk *clk;
+		bool regulator_on;
 		int index;
 	} phys[MAX_PHYS];
+	/* phy0 / otg related variables */
+	bool phy0_init;
+	bool phy0_poll;
+	struct gpio_desc *id_det_gpio;
+	struct gpio_desc *vbus_det_gpio;
+	int id_det_irq;
+	int vbus_det_irq;
+	int id_det;
+	int vbus_det;
+	struct delayed_work detect;
 };
 
 #define to_sun4i_usb_phy_data(phy) \
 	container_of((phy), struct sun4i_usb_phy_data, phys[(phy)->index])
 
+static void sun4i_usb_phy0_update_iscr(struct phy *_phy, u32 clr, u32 set)
+{
+	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
+	struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
+	u32 iscr;
+
+	iscr = readl(data->base + REG_ISCR);
+	iscr &= ~clr;
+	iscr |= set;
+	writel(iscr, data->base + REG_ISCR);
+}
+
+static void sun4i_usb_phy0_set_id_detect(struct phy *phy, u32 val)
+{
+	if (val)
+		val = ISCR_FORCE_ID_HIGH;
+	else
+		val = ISCR_FORCE_ID_LOW;
+
+	sun4i_usb_phy0_update_iscr(phy, ISCR_FORCE_ID_MASK, val);
+}
+
+static void sun4i_usb_phy0_set_vbus_detect(struct phy *phy, u32 val)
+{
+	if (val)
+		val = ISCR_FORCE_VBUS_HIGH;
+	else
+		val = ISCR_FORCE_VBUS_LOW;
+
+	sun4i_usb_phy0_update_iscr(phy, ISCR_FORCE_VBUS_MASK, val);
+}
+
 static void sun4i_usb_phy_write(struct sun4i_usb_phy *phy, u32 addr, u32 data,
 				int len)
 {
@@ -171,12 +235,39 @@ static int sun4i_usb_phy_init(struct phy *_phy)
 
 	sun4i_usb_phy_passby(phy, 1);
 
+	if (phy->index == 0) {
+		data->phy0_init = true;
+
+		/* Enable pull-ups */
+		sun4i_usb_phy0_update_iscr(_phy, 0, ISCR_DPDM_PULLUP_EN);
+		sun4i_usb_phy0_update_iscr(_phy, 0, ISCR_ID_PULLUP_EN);
+
+		if (data->id_det_gpio) {
+			/* OTG mode, force ISCR and cable state updates */
+			data->id_det = -1;
+			data->vbus_det = -1;
+			queue_delayed_work(system_wq, &data->detect, 0);
+		} else {
+			/* Host only mode */
+			sun4i_usb_phy0_set_id_detect(_phy, 0);
+			sun4i_usb_phy0_set_vbus_detect(_phy, 1);
+		}
+	}
+
 	return 0;
 }
 
 static int sun4i_usb_phy_exit(struct phy *_phy)
 {
 	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
+	struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
+
+	if (phy->index == 0) {
+		/* Disable pull-ups */
+		sun4i_usb_phy0_update_iscr(_phy, ISCR_DPDM_PULLUP_EN, 0);
+		sun4i_usb_phy0_update_iscr(_phy, ISCR_ID_PULLUP_EN, 0);
+		data->phy0_init = false;
+	}
 
 	sun4i_usb_phy_passby(phy, 0);
 	reset_control_assert(phy->reset);
@@ -188,20 +279,46 @@ static int sun4i_usb_phy_exit(struct phy *_phy)
 static int sun4i_usb_phy_power_on(struct phy *_phy)
 {
 	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
-	int ret = 0;
+	struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
+	int ret;
+
+	if (!phy->vbus || phy->regulator_on)
+		return 0;
+
+	/* For phy0 only turn on Vbus if we don't have an ext. Vbus */
+	if (phy->index == 0 && data->vbus_det)
+		return 0;
 
-	if (phy->vbus)
-		ret = regulator_enable(phy->vbus);
+	ret = regulator_enable(phy->vbus);
+	if (ret)
+		return ret;
 
-	return ret;
+	phy->regulator_on = true;
+
+	/* We must report Vbus high within OTG_TIME_A_WAIT_VRISE msec. */
+	if (phy->index == 0 && data->phy0_poll)
+		mod_delayed_work(system_wq, &data->detect, DEBOUNCE_TIME);
+
+	return 0;
 }
 
 static int sun4i_usb_phy_power_off(struct phy *_phy)
 {
 	struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
+	struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
+
+	if (!phy->vbus || !phy->regulator_on)
+		return 0;
 
-	if (phy->vbus)
-		regulator_disable(phy->vbus);
+	regulator_disable(phy->vbus);
+	phy->regulator_on = false;
+
+	/*
+	 * phy0 vbus typically slowly discharges, sometimes this causes the
+	 * Vbus gpio to not trigger an edge irq on Vbus off, so force a rescan.
+	 */
+	if (phy->index == 0 && !data->phy0_poll)
+		mod_delayed_work(system_wq, &data->detect, POLL_TIME);
 
 	return 0;
 }
@@ -221,6 +338,49 @@ static struct phy_ops sun4i_usb_phy_ops = {
 	.owner		= THIS_MODULE,
 };
 
+static void sun4i_usb_phy0_id_vbus_det_scan(struct work_struct *work)
+{
+	struct sun4i_usb_phy_data *data =
+		container_of(work, struct sun4i_usb_phy_data, detect.work);
+	struct phy *phy0 = data->phys[0].phy;
+	int id_det, vbus_det;
+
+	id_det = gpiod_get_value_cansleep(data->id_det_gpio);
+	vbus_det = gpiod_get_value_cansleep(data->vbus_det_gpio);
+
+	mutex_lock(&phy0->mutex);
+
+	if (!data->phy0_init) {
+		mutex_unlock(&phy0->mutex);
+		return;
+	}
+
+	if (id_det != data->id_det) {
+		sun4i_usb_phy0_set_id_detect(phy0, id_det);
+		data->id_det = id_det;
+	}
+
+	if (vbus_det != data->vbus_det) {
+		sun4i_usb_phy0_set_vbus_detect(phy0, vbus_det);
+		data->vbus_det = vbus_det;
+	}
+
+	mutex_unlock(&phy0->mutex);
+
+	if (data->phy0_poll)
+		queue_delayed_work(system_wq, &data->detect, POLL_TIME);
+}
+
+static irqreturn_t sun4i_usb_phy0_id_vbus_det_irq(int irq, void *dev_id)
+{
+	struct sun4i_usb_phy_data *data = dev_id;
+
+	/* vbus or id changed, let the pins settle and then scan them */
+	mod_delayed_work(system_wq, &data->detect, DEBOUNCE_TIME);
+
+	return IRQ_HANDLED;
+}
+
 static struct phy *sun4i_usb_phy_xlate(struct device *dev,
 					struct of_phandle_args *args)
 {
@@ -232,6 +392,21 @@ static struct phy *sun4i_usb_phy_xlate(struct device *dev,
 	return data->phys[args->args[0]].phy;
 }
 
+static int sun4i_usb_phy_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sun4i_usb_phy_data *data = dev_get_drvdata(dev);
+
+	if (data->id_det_irq >= 0)
+		devm_free_irq(dev, data->id_det_irq, data);
+	if (data->vbus_det_irq >= 0)
+		devm_free_irq(dev, data->vbus_det_irq, data);
+
+	cancel_delayed_work_sync(&data->detect);
+
+	return 0;
+}
+
 static int sun4i_usb_phy_probe(struct platform_device *pdev)
 {
 	struct sun4i_usb_phy_data *data;
@@ -240,13 +415,15 @@ static int sun4i_usb_phy_probe(struct platform_device *pdev)
 	struct phy_provider *phy_provider;
 	bool dedicated_clocks;
 	struct resource *res;
-	int i;
+	int i, ret;
 
 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
 	mutex_init(&data->mutex);
+	INIT_DELAYED_WORK(&data->detect, sun4i_usb_phy0_id_vbus_det_scan);
+	dev_set_drvdata(dev, data);
 
 	if (of_device_is_compatible(np, "allwinner,sun5i-a13-usb-phy"))
 		data->num_phys = 2;
@@ -269,6 +446,26 @@ static int sun4i_usb_phy_probe(struct platform_device *pdev)
 	if (IS_ERR(data->base))
 		return PTR_ERR(data->base);
 
+	data->id_det_gpio = devm_gpiod_get(dev, "usb0_id_det", GPIOD_IN);
+	if (IS_ERR(data->id_det_gpio)) {
+		if (PTR_ERR(data->id_det_gpio) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		data->id_det_gpio = NULL;
+	}
+
+	data->vbus_det_gpio = devm_gpiod_get(dev, "usb0_vbus_det", GPIOD_IN);
+	if (IS_ERR(data->vbus_det_gpio)) {
+		if (PTR_ERR(data->vbus_det_gpio) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		data->vbus_det_gpio = NULL;
+	}
+
+	/* We either want both gpio pins or neither (when in host mode) */
+	if (!data->id_det_gpio != !data->vbus_det_gpio) {
+		dev_err(dev, "failed to get id or vbus detect pin\n");
+		return -ENODEV;
+	}
+
 	for (i = 0; i < data->num_phys; i++) {
 		struct sun4i_usb_phy *phy = data->phys + i;
 		char name[16];
@@ -318,10 +515,42 @@ static int sun4i_usb_phy_probe(struct platform_device *pdev)
 		phy_set_drvdata(phy->phy, &data->phys[i]);
 	}
 
-	dev_set_drvdata(dev, data);
+	data->id_det_irq = gpiod_to_irq(data->id_det_gpio);
+	data->vbus_det_irq = gpiod_to_irq(data->vbus_det_gpio);
+	if (data->id_det_irq  < 0 || data->vbus_det_irq < 0)
+		data->phy0_poll = true;
+
+	if (data->id_det_irq >= 0) {
+		ret = devm_request_irq(dev, data->id_det_irq,
+				sun4i_usb_phy0_id_vbus_det_irq,
+				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+				"usb0-id-det", data);
+		if (ret) {
+			dev_err(dev, "Err requesting id-det-irq: %d\n", ret);
+			return ret;
+		}
+	}
+
+	if (data->vbus_det_irq >= 0) {
+		ret = devm_request_irq(dev, data->vbus_det_irq,
+				sun4i_usb_phy0_id_vbus_det_irq,
+				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+				"usb0-vbus-det", data);
+		if (ret) {
+			dev_err(dev, "Err requesting vbus-det-irq: %d\n", ret);
+			data->vbus_det_irq = -1;
+			sun4i_usb_phy_remove(pdev); /* Stop detect work */
+			return ret;
+		}
+	}
+
 	phy_provider = devm_of_phy_provider_register(dev, sun4i_usb_phy_xlate);
+	if (IS_ERR(phy_provider)) {
+		sun4i_usb_phy_remove(pdev); /* Stop detect work */
+		return PTR_ERR(phy_provider);
+	}
 
-	return PTR_ERR_OR_ZERO(phy_provider);
+	return 0;
 }
 
 static const struct of_device_id sun4i_usb_phy_of_match[] = {
@@ -335,6 +564,7 @@ MODULE_DEVICE_TABLE(of, sun4i_usb_phy_of_match);
 
 static struct platform_driver sun4i_usb_phy_driver = {
 	.probe	= sun4i_usb_phy_probe,
+	.remove	= sun4i_usb_phy_remove,
 	.driver = {
 		.of_match_table	= sun4i_usb_phy_of_match,
 		.name  = "sun4i-usb-phy",