regulator: Add 'start-up time' to fixed voltage regulators

Add a field to specify a delay for the start-up time of
a fixed voltage regulator.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/fixed.c

@@ -24,12 +24,14 @@
 #include <linux/regulator/driver.h>
 #include <linux/regulator/fixed.h>
 #include <linux/gpio.h>
+#include <linux/delay.h>
 
 struct fixed_voltage_data {
 	struct regulator_desc desc;
 	struct regulator_dev *dev;
 	int microvolts;
 	int gpio;
+	unsigned startup_delay;
 	unsigned enable_high:1;
 	unsigned is_enabled:1;
 };
@@ -48,6 +50,8 @@ static int fixed_voltage_enable(struct regulator_dev *dev)
 	if (gpio_is_valid(data->gpio)) {
 		gpio_set_value_cansleep(data->gpio, data->enable_high);
 		data->is_enabled = 1;
+		if (data->startup_delay)
+			udelay(data->startup_delay);
 	}
 
 	return 0;
@@ -117,6 +121,7 @@ static int regulator_fixed_voltage_probe(struct platform_device *pdev)
 
 	drvdata->microvolts = config->microvolts;
 	drvdata->gpio = config->gpio;
+	drvdata->startup_delay = config->startup_delay;
 
 	if (gpio_is_valid(config->gpio)) {
 		drvdata->enable_high = config->enable_high;

include/linux/regulator/fixed.h

@@ -25,6 +25,7 @@ struct regulator_init_data;
  * @microvolts:		Output voltage of regulator
  * @gpio:		GPIO to use for enable control
  * 			set to -EINVAL if not used
+ * @startup_delay:	Start-up time in microseconds
  * @enable_high:	Polarity of enable GPIO
  *			1 = Active high, 0 = Active low
  * @enabled_at_boot:	Whether regulator has been enabled at
@@ -41,6 +42,7 @@ struct fixed_voltage_config {
 	const char *supply_name;
 	int microvolts;
 	int gpio;
+	unsigned startup_delay;
 	unsigned enable_high:1;
 	unsigned enabled_at_boot:1;
 	struct regulator_init_data *init_data;