[RFC v4 08/14] power: pwrseq: simple: Add support for regulators and generic property

Krzysztof Kozlowski
2016-06-09T09:44:25Z

Some devices need real hard-reset by cutting the power. During power
sequence turn off and on all of provided regulators.

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, supplies etc.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
---
.../bindings/power/pwrseq/pwrseq-simple.txt | 30 +++++-
drivers/power/pwrseq/pwrseq_simple.c | 113 ++++++++++++++++++++-
2 files changed, 136 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..7e5a414a67fc 100644
--- a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-simple.txt
+++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-simple.txt
@@ -1,11 +1,18 @@
-* 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. Property for any node
+ Required properties:
+ - power-sequence
+
+2. Separate node (not recommended for new users)
+ Required properties:
+ - compatible : contains "mmc-pwrseq-simple".
+

Optional properties:
- reset-gpios : contains a list of GPIO specifiers. The reset GPIOs are asserted
@@ -16,6 +23,8 @@ Optional properties:
See ../clocks/clock-bindings.txt for details.
- clock-names : Must include the following entry:
"ext_clock" (External clock provided to the card).
+- *-supply : If supplies are provided, the driver will enable and disable
+ them during power sequence.

Example:

@@ -25,3 +34,16 @@ Example:
clocks = <&clk_32768_ck>;
clock-names = "ext_clock";
}
+
+ 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;
+ vdd-supply = <&buck8_reg>;
+ };
diff --git a/drivers/power/pwrseq/pwrseq_simple.c b/drivers/power/pwrseq/pwrseq_simple.c
index 93807a6ef162..f70e207f994b 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 +19,25 @@
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+#include <linux/regulator/of_regulator.h>
#include <linux/pwrseq.h>
+#include <linux/delay.h>
+
+static LIST_HEAD(mmc_pwrseq_devs);
+
+struct mmc_pwrseq_dev {
+ struct platform_device *pdev;
+ struct list_head entry;
+};

struct mmc_pwrseq_simple {
struct pwrseq pwrseq;
bool clk_enabled;
struct clk *ext_clk;
struct gpio_descs *reset_gpios;
+ unsigned int regulator_count;
+ struct regulator_bulk_data *regulators;
};

#define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
@@ -60,6 +75,14 @@ static void mmc_pwrseq_simple_post_power_on(struct pwrseq *_pwrseq)
{
struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(_pwrseq);

+ if (pwrseq->regulators) {
+ int err;
+
+ err = regulator_bulk_enable(pwrseq->regulator_count,
+ pwrseq->regulators);
+ WARN_ON_ONCE(err);
+ }
+
mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
}

@@ -73,6 +96,14 @@ static void mmc_pwrseq_simple_power_off(struct pwrseq *_pwrseq)
clk_disable_unprepare(pwrseq->ext_clk);
pwrseq->clk_enabled = false;
}
+
+ if (pwrseq->regulators) {
+ int err;
+
+ err = regulator_bulk_disable(pwrseq->regulator_count,
+ pwrseq->regulators);
+ WARN_ON_ONCE(err);
+ }
}

static const struct pwrseq_ops mmc_pwrseq_simple_ops = {
@@ -91,6 +122,7 @@ static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
{
struct mmc_pwrseq_simple *pwrseq;
struct device *dev = &pdev->dev;
+ int err;

pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
if (!pwrseq)
@@ -100,12 +132,39 @@ 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);

+ err = devm_of_regulator_all_get(dev, &pwrseq->regulator_count,
+ &pwrseq->regulators);
+ if (err)
+ return err;
+
+ if (pwrseq->regulators) {
+ /*
+ * 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_bulk_enable(pwrseq->regulator_count,
+ pwrseq->regulators);
+ WARN_ON_ONCE(err);
+
+ err = regulator_bulk_disable(pwrseq->regulator_count,
+ pwrseq->regulators);
+ 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 +181,14 @@ static int mmc_pwrseq_simple_remove(struct platform_device *pdev)

pwrseq_unregister(&pwrseq->pwrseq);

+ if (pwrseq->regulators) {
+ int err;
+
+ err = regulator_bulk_disable(pwrseq->regulator_count,
+ pwrseq->regulators);
+ WARN_ON_ONCE(err);
+ }
+
return 0;
}

@@ -134,5 +201,45 @@ 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 mmc_pwrseq_dev *pwrseq_dev;
+ 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))
+ continue;
+
+ pwrseq_dev = kzalloc(sizeof(*pwrseq_dev), GFP_KERNEL);
+ if (!pwrseq_dev)
+ continue;
+
+ of_node_get(np);
+ pdev->dev.of_node = np;
+ pwrseq_dev->pdev = pdev;
+ list_add(&pwrseq_dev->entry, &mmc_pwrseq_devs);
+ }
+
+ return platform_driver_register(&mmc_pwrseq_simple_driver);
+}
+module_init(mmc_pwrseq_simple_driver_init);
+
+static void __exit mmc_pwrseq_simple_driver_exit(void)
+{
+ struct mmc_pwrseq_dev *pwrseq_dev, *tmp;
+
+ list_for_each_entry_safe(pwrseq_dev, tmp, &mmc_pwrseq_devs, entry) {
+ list_del(&pwrseq_dev->entry);
+ of_node_put(pwrseq_dev->pdev->dev.of_node);
+ platform_device_unregister(pwrseq_dev->pdev);
+ kfree(pwrseq_dev);
+ }
+
+ platform_driver_unregister(&mmc_pwrseq_simple_driver);
+}
+module_exit(mmc_pwrseq_simple_driver_exit);
MODULE_LICENSE("GPL v2");
--
1.9.1