regulator: fixed: add off-on-delay

Depends on board design, the gpio controlling regulator may
connects with a big capacitance. When need off, it takes some time
to let the regulator to be truly off. If not add enough delay, the
regulator might have always been on, so introduce off-on-delay to
handle such case.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1572311875-22880-3-git-send-email-peng.fan@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/fixed.c

@@ -123,6 +123,7 @@ of_get_fixed_voltage_config(struct device *dev,
 		config->enabled_at_boot = true;
 
 	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
+	of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
 
 	if (of_find_property(np, "vin-supply", NULL))
 		config->input_supply = "vin";
@@ -189,6 +190,7 @@ static int reg_fixed_voltage_probe(struct platform_device *pdev)
 	}
 
 	drvdata->desc.enable_time = config->startup_delay;
+	drvdata->desc.off_on_delay = config->off_on_delay;
 
 	if (config->input_supply) {
 		drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,

include/linux/regulator/fixed.h

@@ -36,6 +36,7 @@ struct fixed_voltage_config {
 	const char *input_supply;
 	int microvolts;
 	unsigned startup_delay;
+	unsigned int off_on_delay;
 	unsigned enabled_at_boot:1;
 	struct regulator_init_data *init_data;
 };