[PATCH v2 04/10] Input: ams_delta_serio: Replace power GPIO with regulator

[Janusz Krzysztofik]

Modify the driver so it no longer requests and manipulates the
"keybrd_pwr" GPIO pin but a "vcc" regulator supply instead.

For this to work with Amstrad Delta, define a regulator over the
"keybrd_pwr" GPIO pin with the "vcc" supply for ams-delta-serio device
and register it from the board file.  Both assign an absulute GPIO
number to the soon depreciated .gpio member of the regulator config
structure, and also build and register a GPIO lookup table so it is
ready for use by the regulator driver as soon as its upcoming update
is applied.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx>
---
Changelog:
v2: - extended comment above error code conversion, thanks Dmitry for 
      requesting that,
    - rebased on v4.18-rc1, no conflicts.

 arch/arm/mach-omap1/board-ams-delta.c | 63 +++++++++++++++++++++++++++++++++--
 drivers/input/serio/ams_delta_serio.c | 37 +++++++++++++++-----
 2 files changed, 89 insertions(+), 11 deletions(-)

diff --git a/arch/arm/mach-omap1/board-ams-delta.c b/arch/arm/mach-omap1/board-ams-delta.c
index 2119d2d3ba84..706eb2f9301d 100644
--- a/arch/arm/mach-omap1/board-ams-delta.c
+++ b/arch/arm/mach-omap1/board-ams-delta.c
@@ -509,6 +509,46 @@ static struct platform_device ams_delta_serio_device = {
 	.id		= PLATFORM_DEVID_NONE,
 };
 
+static struct regulator_consumer_supply keybrd_pwr_consumers[] = {
+	/*
+	 * Initialize supply .dev_name with NULL.  It will be replaced
+	 * with serio dev_name() as soon as the serio device is registered.
+	 */
+	REGULATOR_SUPPLY("vcc", NULL),
+};
+
+static struct regulator_init_data keybrd_pwr_initdata = {
+	.constraints		= {
+		.valid_ops_mask		= REGULATOR_CHANGE_STATUS,
+	},
+	.num_consumer_supplies	= ARRAY_SIZE(keybrd_pwr_consumers),
+	.consumer_supplies	= keybrd_pwr_consumers,
+};
+
+static struct fixed_voltage_config keybrd_pwr_config = {
+	.supply_name		= "keybrd_pwr",
+	.microvolts		= 5000000,
+	.gpio			= AMS_DELTA_GPIO_PIN_KEYBRD_PWR,
+	.enable_high		= 1,
+	.init_data		= &keybrd_pwr_initdata,
+};
+
+static struct platform_device keybrd_pwr_device = {
+	.name	= "reg-fixed-voltage",
+	.id	= PLATFORM_DEVID_AUTO,
+	.dev	= {
+		.platform_data	= &keybrd_pwr_config,
+	},
+};
+
+static struct gpiod_lookup_table keybrd_pwr_gpio_table = {
+	.table = {
+		GPIO_LOOKUP(LATCH2_LABEL, LATCH2_PIN_KEYBRD_PWR, NULL,
+			    GPIO_ACTIVE_HIGH),
+		{ },
+	},
+};
+
 static struct platform_device *ams_delta_devices[] __initdata = {
 	&latch1_gpio_device,
 	&latch2_gpio_device,
@@ -526,6 +566,7 @@ static struct platform_device *late_devices[] __initdata = {
 
 static struct gpiod_lookup_table *ams_delta_gpio_tables[] __initdata = {
 	&ams_delta_audio_gpio_table,
+	&keybrd_pwr_gpio_table,
 };
 
 static struct gpiod_lookup_table *late_gpio_tables[] __initdata = {
@@ -566,12 +607,30 @@ static void __init ams_delta_init(void)
 	platform_add_devices(ams_delta_devices, ARRAY_SIZE(ams_delta_devices));
 
 	/*
-	 * As soon as devices have been registered, assign their dev_names
-	 * to respective GPIO lookup tables before they are added.
+	 * As soon as regulator consumers have been registered, assign their
+	 * dev_names to consumer supply entries of respective regulators.
+	 */
+	keybrd_pwr_consumers[0].dev_name =
+			dev_name(&ams_delta_serio_device.dev);
+
+	/*
+	 * Once consumer supply entries are populated with dev_names,
+	 * register regulator devices.  At this stage only the keyboard
+	 * power regulator has its consumer supply table fully populated.
+	 */
+	platform_device_register(&keybrd_pwr_device);
+
+	/*
+	 * As soon as GPIO consumers have been registered, assign
+	 * their dev_names to respective GPIO lookup tables.
 	 */
 	ams_delta_audio_gpio_table.dev_id =
 			dev_name(&ams_delta_audio_device.dev);
+	keybrd_pwr_gpio_table.dev_id = dev_name(&keybrd_pwr_device.dev);
 
+	/*
+	 * Once GPIO lookup tables are populated with dev_names, register them.
+	 */
 	gpiod_add_lookup_tables(ams_delta_gpio_tables,
 				ARRAY_SIZE(ams_delta_gpio_tables));
 
diff --git a/drivers/input/serio/ams_delta_serio.c b/drivers/input/serio/ams_delta_serio.c
index 551a4fa73fe4..854d0d3ada52 100644
--- a/drivers/input/serio/ams_delta_serio.c
+++ b/drivers/input/serio/ams_delta_serio.c
@@ -23,6 +23,7 @@
 #include <linux/gpio.h>
 #include <linux/irq.h>
 #include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
 #include <linux/serio.h>
 #include <linux/slab.h>
 #include <linux/module.h>
@@ -39,6 +40,7 @@ MODULE_LICENSE("GPL");
 
 struct ams_delta_serio {
 	struct serio *serio;
+	struct regulator *vcc;
 };
 
 static int check_data(struct serio *serio, int data)
@@ -94,16 +96,18 @@ static irqreturn_t ams_delta_serio_interrupt(int irq, void *dev_id)
 
 static int ams_delta_serio_open(struct serio *serio)
 {
-	/* enable keyboard */
-	gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 1);
+	struct ams_delta_serio *priv = serio->port_data;
 
-	return 0;
+	/* enable keyboard */
+	return regulator_enable(priv->vcc);
 }
 
 static void ams_delta_serio_close(struct serio *serio)
 {
+	struct ams_delta_serio *priv = serio->port_data;
+
 	/* disable keyboard */
-	gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 0);
+	regulator_disable(priv->vcc);
 }
 
 static const struct gpio ams_delta_gpios[] __initconst_or_module = {
@@ -117,11 +121,6 @@ static const struct gpio ams_delta_gpios[] __initconst_or_module = {
 		.flags	= GPIOF_DIR_IN,
 		.label	= "serio-clock",
 	},
-	{
-		.gpio	= AMS_DELTA_GPIO_PIN_KEYBRD_PWR,
-		.flags	= GPIOF_OUT_INIT_LOW,
-		.label	= "serio-power",
-	},
 	{
 		.gpio	= AMS_DELTA_GPIO_PIN_KEYBRD_DATAOUT,
 		.flags	= GPIOF_OUT_INIT_LOW,
@@ -146,6 +145,26 @@ static int ams_delta_serio_init(struct platform_device *pdev)
 		goto serio;
 	}
 
+	priv->vcc = devm_regulator_get(&pdev->dev, "vcc");
+	if (IS_ERR(priv->vcc)) {
+		err = PTR_ERR(priv->vcc);
+		dev_err(&pdev->dev, "regulator request failed (%d)\n", err);
+		/*
+		 * When running on a non-dt platform and requested regulator
+		 * is not available, devm_regulator_get() never returns
+		 * -EPROBE_DEFER as it is not able to justify if the regulator
+		 * may still appear later.  On the other hand, the board can
+		 * still set full constriants flag at late_initcall in order
+		 * to instruct devm_regulator_get() to returnn a dummy one
+		 * if sufficient.  Hence, if we get -ENODEV here, let's convert
+		 * it to -EPROBE_DEFER and wait for the board to decide or
+		 * let Deferred Probe infrastructure handle this error.
+		 */
+		if (err == -ENODEV)
+			err = -EPROBE_DEFER;
+		goto gpio;
+	}
+
 	err = request_irq(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
 			ams_delta_serio_interrupt, IRQ_TYPE_EDGE_RISING,
 			DRIVER_NAME, priv);
-- 
2.16.4