[PATCH v3 06/12] power: pwrseq: simple: Add support for regulator and generic property

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

Some devices need real hard-reset by cutting the power.  During power
sequence turn off and on the regulator, if it is provided.

Additionally add support for instantiating the pwrseq-simple device on a
generic property 'power-sequence'.  The device will attach itself to the
node containing the property and parse the node's properties like
reset-gpios, ext-supply etc.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
---
 .../bindings/power/pwrseq/pwrseq-simple.txt        | 29 +++++++-
 drivers/power/pwrseq/pwrseq_simple.c               | 85 +++++++++++++++++++++-
 2 files changed, 107 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-simple.txt b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-simple.txt
index ce0e76749671..a8c3f13ee83f 100644
--- a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-simple.txt
+++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-simple.txt
@@ -1,11 +1,17 @@
-* The simple MMC power sequence provider
+* The simple power sequence provider
 
-The purpose of the simple MMC power sequence provider is to supports a set of
+The purpose of the simple power sequence provider is to supports a set of
 common properties between various SOC designs. It thus enables us to use the
 same provider for several SOC designs.
 
-Required properties:
-- compatible : contains "mmc-pwrseq-simple".
+The driver supports two types of bindings:
+1. Separate node
+   Required properties:
+   - compatible : contains "mmc-pwrseq-simple".
+
+2. Property for any node
+   Required properties:
+   - power-sequence
 
 Optional properties:
 - reset-gpios : contains a list of GPIO specifiers. The reset GPIOs are asserted
@@ -16,6 +22,7 @@ Optional properties:
   See ../clocks/clock-bindings.txt for details.
 - clock-names : Must include the following entry:
   "ext_clock" (External clock provided to the card).
+- ext-supply : External regulator supply
 
 Example:
 
@@ -24,4 +31,18 @@ Example:
 		reset-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>;
 		clocks = <&clk_32768_ck>;
 		clock-names = "ext_clock";
+		ext-supply = <&buck8>;
 	}
+
+	usb3503@08 {
+		compatible = "smsc,usb3503";
+		reg = <0x08>;
+
+		intn-gpios = <&gpx3 0 GPIO_ACTIVE_HIGH>;
+		connect-gpios = <&gpx3 4 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&gpx3 5 GPIO_ACTIVE_HIGH>;
+		initial-mode = <1>;
+
+		power-sequence;
+		ext-supply = <&buck8_reg>;
+	};
diff --git a/drivers/power/pwrseq/pwrseq_simple.c b/drivers/power/pwrseq/pwrseq_simple.c
index 93807a6ef162..4096261b16a4 100644
--- a/drivers/power/pwrseq/pwrseq_simple.c
+++ b/drivers/power/pwrseq/pwrseq_simple.c
@@ -1,12 +1,15 @@
 /*
- *  Copyright (C) 2014 Linaro Ltd
+ * Copyright (C) 2014 Linaro Ltd
+ * Copyright (C) 2016 Samsung Electronics
  *
  * Author: Ulf Hansson <ulf.hansson@linaro.org>
+ *         Krzysztof Kozlowski <k.kozlowski@samsung.com>
  *
  * License terms: GNU General Public License (GPL) version 2
  *
  *  Simple MMC power sequence management
  */
+#include <linux/of.h>
 #include <linux/clk.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -16,13 +19,16 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
 #include <linux/pwrseq.h>
+#include <linux/delay.h>
 
 struct mmc_pwrseq_simple {
 	struct pwrseq pwrseq;
 	bool clk_enabled;
 	struct clk *ext_clk;
 	struct gpio_descs *reset_gpios;
+	struct regulator *ext_reg;
 };
 
 #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
@@ -60,6 +66,13 @@ static void mmc_pwrseq_simple_post_power_on(struct pwrseq *_pwrseq)
 {
 	struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(_pwrseq);
 
+	if (pwrseq->ext_reg) {
+		int err;
+
+		err = regulator_enable(pwrseq->ext_reg);
+		WARN_ON_ONCE(err);
+	}
+
 	mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
 }
 
@@ -73,6 +86,13 @@ static void mmc_pwrseq_simple_power_off(struct pwrseq *_pwrseq)
 		clk_disable_unprepare(pwrseq->ext_clk);
 		pwrseq->clk_enabled = false;
 	}
+
+	if (pwrseq->ext_reg) {
+		int err;
+
+		err = regulator_disable(pwrseq->ext_reg);
+		WARN_ON_ONCE(err);
+	}
 }
 
 static const struct pwrseq_ops mmc_pwrseq_simple_ops = {
@@ -100,12 +120,40 @@ static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
 	if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
 		return PTR_ERR(pwrseq->ext_clk);
 
+	pwrseq->ext_reg = devm_regulator_get_optional(dev, "ext");
+	if (IS_ERR(pwrseq->ext_reg)) {
+		if (PTR_ERR(pwrseq->ext_reg) == -ENODEV)
+			pwrseq->ext_reg = NULL;
+		else
+			return PTR_ERR(pwrseq->ext_reg);
+	} else {
+		int err;
+		/*
+		 * Be sure that regulator is off, before the driver will start
+		 * power sequence. It is likely that regulator is on by default
+		 * and it without toggling it here, it would be disabled much
+		 * later by the core.
+		 */
+
+		err = regulator_enable(pwrseq->ext_reg);
+		WARN_ON_ONCE(err);
+
+		err = regulator_disable(pwrseq->ext_reg);
+		WARN_ON_ONCE(err);
+	}
+
 	pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset",
 							GPIOD_OUT_HIGH);
 	if (IS_ERR(pwrseq->reset_gpios) &&
 	    PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
 	    PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
-		return PTR_ERR(pwrseq->reset_gpios);
+		/*
+		 * Don't care about errors. If this pwrseq device was added
+		 * to node with existing reset-gpios, then the GPIO reset will
+		 * be handled by other device.
+		 */
+		dev_warn(dev, "Cannot get reset gpio: %ld\n",
+			 PTR_ERR(pwrseq->reset_gpios));
 	}
 
 	pwrseq->pwrseq.dev = dev;
@@ -122,6 +170,13 @@ static int mmc_pwrseq_simple_remove(struct platform_device *pdev)
 
 	pwrseq_unregister(&pwrseq->pwrseq);
 
+	if (pwrseq->ext_reg) {
+		int err;
+
+		err = regulator_disable(pwrseq->ext_reg);
+		WARN_ON_ONCE(err);
+	}
+
 	return 0;
 }
 
@@ -134,5 +189,29 @@ static struct platform_driver mmc_pwrseq_simple_driver = {
 	},
 };
 
-module_platform_driver(mmc_pwrseq_simple_driver);
+static int __init mmc_pwrseq_simple_driver_init(void)
+{
+	struct platform_device *pdev;
+	struct device_node *np;
+
+	for_each_node_with_property(np, "power-sequence") {
+		pdev = platform_device_register_simple("pwrseq_simple",
+						       PLATFORM_DEVID_AUTO,
+						       NULL, 0);
+		if (!IS_ERR(pdev)) {
+			of_node_get(np);
+			pdev->dev.of_node = np;
+		}
+	}
+
+	return platform_driver_register(&mmc_pwrseq_simple_driver);
+}
+module_init(mmc_pwrseq_simple_driver_init);
+
+static void __exit mmc_pwrseq_simple_driver_exit(void)
+{
+	/* FIXME: of_node_put? */
+	platform_driver_unregister(&mmc_pwrseq_simple_driver);
+}
+module_exit(mmc_pwrseq_simple_driver_exit);
 MODULE_LICENSE("GPL v2");
-- 
1.9.1