regulator: s2mps11: Add external GPIO control for S2MPS14

Add support for external control over GPIO for LDO10, LDO11 and LDO12
S2MPS14 regulators. External control can be turned on by writing 0x0 to
control register which in case of other regulators is used for disabling
them. These LDO10-LDO12 regulators can be disabled only by I2C GPIO or
PWREN pin so the patch actually allows proper way of disabling them.

Additionally the GPIO control has two benefits:
 - It is faster than toggling it over I2C bus.
 - It allows disabling the regulator during suspend to RAM; The AP will
   enable it during resume.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/regulator/s2mps11.c

@@ -27,6 +27,7 @@
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/of_regulator.h>
+#include <linux/of_gpio.h>
 #include <linux/mfd/samsung/core.h>
 #include <linux/mfd/samsung/s2mps11.h>
 #include <linux/mfd/samsung/s2mps14.h>
@@ -44,6 +45,8 @@ struct s2mps11_info {
 	 * was enabled.
 	 */
 	unsigned int s2mps14_suspend_state:30;
+	/* Array of size rdev_num with GPIO-s for external sleep control */
+	int *ext_control_gpio;
 };
 
 static int get_ramp_delay(int ramp_delay)
@@ -409,6 +412,8 @@ static int s2mps14_regulator_enable(struct regulator_dev *rdev)
 
 	if (s2mps11->s2mps14_suspend_state & (1 << rdev_get_id(rdev)))
 		val = S2MPS14_ENABLE_SUSPEND;
+	else if (s2mps11->ext_control_gpio[rdev_get_id(rdev)])
+		val = S2MPS14_ENABLE_EXT_CONTROL;
 	else
 		val = rdev->desc->enable_mask;
 
@@ -565,8 +570,40 @@ static const struct regulator_desc s2mps14_regulators[] = {
 	regulator_desc_s2mps14_buck1235(5),
 };
 
-static int s2mps11_pmic_dt_parse(struct platform_device *pdev,
+static int s2mps14_pmic_enable_ext_control(struct s2mps11_info *s2mps11,
+		struct regulator_dev *rdev)
+{
+	return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+			rdev->desc->enable_mask, S2MPS14_ENABLE_EXT_CONTROL);
+}
+
+static void s2mps14_pmic_dt_parse_ext_control_gpio(struct platform_device *pdev,
 		struct of_regulator_match *rdata, struct s2mps11_info *s2mps11)
+{
+	int *gpio = s2mps11->ext_control_gpio;
+	unsigned int i;
+	unsigned int valid_regulators[3] = { S2MPS14_LDO10, S2MPS14_LDO11,
+		S2MPS14_LDO12 };
+
+	for (i = 0; i < ARRAY_SIZE(valid_regulators); i++) {
+		unsigned int reg = valid_regulators[i];
+
+		if (!rdata[reg].init_data || !rdata[reg].of_node)
+			continue;
+
+		gpio[reg] = of_get_named_gpio(rdata[reg].of_node,
+				"samsung,ext-control-gpios", 0);
+		if (!gpio_is_valid(gpio[reg]))
+			gpio[reg] = 0;
+		else
+			dev_dbg(&pdev->dev, "Using GPIO %d for ext-control over %d/%s\n",
+					gpio[reg], reg, rdata[reg].name);
+	}
+}
+
+static int s2mps11_pmic_dt_parse(struct platform_device *pdev,
+		struct of_regulator_match *rdata, struct s2mps11_info *s2mps11,
+		enum sec_device_type dev_type)
 {
 	struct device_node *reg_np;
 
@@ -577,6 +614,9 @@ static int s2mps11_pmic_dt_parse(struct platform_device *pdev,
 	}
 
 	of_regulator_match(&pdev->dev, reg_np, rdata, s2mps11->rdev_num);
+	if (dev_type == S2MPS14X)
+		s2mps14_pmic_dt_parse_ext_control_gpio(pdev, rdata, s2mps11);
+
 	of_node_put(reg_np);
 
 	return 0;
@@ -613,6 +653,12 @@ static int s2mps11_pmic_probe(struct platform_device *pdev)
 		return -EINVAL;
 	};
 
+	s2mps11->ext_control_gpio = devm_kzalloc(&pdev->dev,
+			sizeof(*s2mps11->ext_control_gpio) * s2mps11->rdev_num,
+			GFP_KERNEL);
+	if (!s2mps11->ext_control_gpio)
+		return -ENOMEM;
+
 	if (!iodev->dev->of_node) {
 		if (iodev->pdata) {
 			pdata = iodev->pdata;
@@ -631,7 +677,7 @@ static int s2mps11_pmic_probe(struct platform_device *pdev)
 	for (i = 0; i < s2mps11->rdev_num; i++)
 		rdata[i].name = regulators[i].name;
 
-	ret = s2mps11_pmic_dt_parse(pdev, rdata, s2mps11);
+	ret = s2mps11_pmic_dt_parse(pdev, rdata, s2mps11, dev_type);
 	if (ret)
 		goto out;
 
@@ -652,6 +698,12 @@ common_reg:
 			config.of_node = rdata[i].of_node;
 		}
 
+		if (s2mps11->ext_control_gpio[i]) {
+			config.ena_gpio = s2mps11->ext_control_gpio[i];
+			config.ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
+		} else
+			config.ena_gpio = config.ena_gpio_flags = 0;
+
 		regulator = devm_regulator_register(&pdev->dev,
 						&regulators[i], &config);
 		if (IS_ERR(regulator)) {
@@ -660,6 +712,17 @@ common_reg:
 				i);
 			goto out;
 		}
+
+		if (s2mps11->ext_control_gpio[i]) {
+			ret = s2mps14_pmic_enable_ext_control(s2mps11,
+					regulator);
+			if (ret < 0) {
+				dev_err(&pdev->dev,
+						"failed to enable GPIO control over %s: %d\n",
+						regulator->desc->name, ret);
+				goto out;
+			}
+		}
 	}
 
 out:

include/linux/mfd/samsung/s2mps14.h

@@ -148,6 +148,8 @@ enum s2mps14_regulators {
 #define S2MPS14_ENABLE_SHIFT		6
 /* On/Off controlled by PWREN */
 #define S2MPS14_ENABLE_SUSPEND		(0x01 << S2MPS14_ENABLE_SHIFT)
+/* On/Off controlled by LDO10EN or EMMCEN */
+#define S2MPS14_ENABLE_EXT_CONTROL	(0x00 << S2MPS14_ENABLE_SHIFT)
 #define S2MPS14_LDO_N_VOLTAGES		(S2MPS14_LDO_VSEL_MASK + 1)
 #define S2MPS14_BUCK_N_VOLTAGES		(S2MPS14_BUCK_VSEL_MASK + 1)