[PATCH v2 10/15] phy: renesas: rcar-gen3-usb2: Add support for PWRRDY

[Claudiu]

From: Claudiu Beznea <claudiu.beznea.uj at bp.renesas.com>

On the Renesas RZ/G3S SoC, the USB PHY has an input signal called PWRRDY.
This signal is managed by the system controller and must be de-asserted
after powering on the area where USB PHY resides and asserted before
powering it off.

The connection b/w the system controller and the USB PHY is implemented
through the renesas,sysc-signal device tree property. This property
specifies the register offset and the bitmask required to control the
signal. The system controller exports the syscon regmap, and the read/write
access to the memory area of the PWRRDY signal is reference-counted, as the
same system controller signal is connected to both RZ/G3S USB PHYs.

Add support for the PWRRDY signal control.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj at bp.renesas.com>
---

Changes in v2:
- none; this patch is new


 drivers/phy/renesas/phy-rcar-gen3-usb2.c | 66 ++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2.c b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
index 59f74aa993ac..84459755adf5 100644
--- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
+++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
@@ -12,12 +12,14 @@
 #include <linux/extcon-provider.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/reset.h>
 #include <linux/string.h>
@@ -111,6 +113,12 @@ struct rcar_gen3_phy {
 	bool powered;
 };
 
+struct rcar_gen3_pwrrdy {
+	struct regmap *regmap;
+	u32 offset;
+	u32 mask;
+};
+
 struct rcar_gen3_chan {
 	void __iomem *base;
 	struct device *dev;	/* platform_device's device */
@@ -118,6 +126,7 @@ struct rcar_gen3_chan {
 	struct rcar_gen3_phy rphys[NUM_OF_PHYS];
 	struct regulator *vbus;
 	struct reset_control *rstc;
+	struct rcar_gen3_pwrrdy *pwrrdy;
 	struct work_struct work;
 	struct mutex lock;	/* protects rphys[...].powered */
 	enum usb_dr_mode dr_mode;
@@ -133,6 +142,7 @@ struct rcar_gen3_phy_drv_data {
 	const struct phy_ops *phy_usb2_ops;
 	bool no_adp_ctrl;
 	bool init_bus;
+	bool pwrrdy;
 };
 
 /*
@@ -587,6 +597,7 @@ static const struct rcar_gen3_phy_drv_data rz_g3s_phy_usb2_data = {
 	.phy_usb2_ops = &rcar_gen3_phy_usb2_ops,
 	.no_adp_ctrl = true,
 	.init_bus = true,
+	.pwrrdy = true,
 };
 
 static const struct of_device_id rcar_gen3_phy_usb2_match_table[] = {
@@ -707,6 +718,55 @@ static int rcar_gen3_phy_usb2_init_bus(struct rcar_gen3_chan *channel)
 	return ret;
 }
 
+static void rcar_gen3_phy_usb2_set_pwrrdy(struct rcar_gen3_chan *channel, bool power_on)
+{
+	struct rcar_gen3_pwrrdy *pwrrdy = channel->pwrrdy;
+
+	/* N/A on this platform. */
+	if (!pwrrdy)
+		return;
+
+	regmap_update_bits(pwrrdy->regmap, pwrrdy->offset, pwrrdy->mask, !power_on);
+}
+
+static void rcar_gen3_phy_usb2_pwrrdy_off(void *data)
+{
+	rcar_gen3_phy_usb2_set_pwrrdy(data, false);
+}
+
+static int rcar_gen3_phy_usb2_init_pwrrdy(struct rcar_gen3_chan *channel)
+{
+	struct device *dev = channel->dev;
+	struct rcar_gen3_pwrrdy *pwrrdy;
+	struct of_phandle_args args;
+	int ret;
+
+	pwrrdy = devm_kzalloc(dev, sizeof(*pwrrdy), GFP_KERNEL);
+	if (!pwrrdy)
+		return -ENOMEM;
+
+	ret = of_parse_phandle_with_args(dev->of_node, "renesas,sysc-signal",
+					 "#renesas,sysc-signal-cells", 0, &args);
+	if (ret)
+		return ret;
+
+	pwrrdy->regmap = syscon_node_to_regmap(args.np);
+	pwrrdy->offset = args.args[0];
+	pwrrdy->mask = args.args[1];
+
+	of_node_put(args.np);
+
+	if (IS_ERR(pwrrdy->regmap))
+		return PTR_ERR(pwrrdy->regmap);
+
+	channel->pwrrdy = pwrrdy;
+
+	/* Power it ON. */
+	rcar_gen3_phy_usb2_set_pwrrdy(channel, true);
+
+	return devm_add_action_or_reset(dev, rcar_gen3_phy_usb2_pwrrdy_off, channel);
+}
+
 static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
 {
 	const struct rcar_gen3_phy_drv_data *phy_data;
@@ -763,6 +823,12 @@ static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, channel);
 	channel->dev = dev;
 
+	if (phy_data->pwrrdy) {
+		ret = rcar_gen3_phy_usb2_init_pwrrdy(channel);
+		if (ret)
+			goto error;
+	}
+
 	if (phy_data->init_bus) {
 		ret = rcar_gen3_phy_usb2_init_bus(channel);
 		if (ret)
-- 
2.39.2