regulator: s5m8767: Use GPIO for controlling Buck9/eMMC

Add support for GPIO control (enable/disable) over Buck9. The Buck9
Converter is used as a supply for eMMC Host Controller.

BUCK9EN GPIO of S5M8767 chip may be used by application processor to
enable or disable the Buck9. This 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; Without the patch the regulator supplying
   eMMC must be defined as fixed-regulator.

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

1 files changed, 84 insertions, 3 deletions

diff --git a/drivers/regulator/s5m8767.c b/drivers/regulator/s5m8767.c
index d7164bb75d3e..6850a25a41c4 100644
--- a/drivers/regulator/s5m8767.c
+++ b/drivers/regulator/s5m8767.c
@@ -11,11 +11,8 @@
  *
  */
 
-#include <linux/bug.h>
 #include <linux/err.h>
-#include <linux/gpio.h>
 #include <linux/of_gpio.h>
-#include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/driver.h>
@@ -483,6 +480,65 @@ static struct regulator_desc regulators[] = {
         s5m8767_regulator_desc(BUCK9),
 };
 
+/*
+ * Enable GPIO control over BUCK9 in regulator_config for that regulator.
+ */
+static void s5m8767_regulator_config_ext_control(struct s5m8767_info *s5m8767,
+                struct sec_regulator_data *rdata,
+                struct regulator_config *config)
+{
+        int i, mode = 0;
+
+        if (rdata->id != S5M8767_BUCK9)
+                return;
+
+        /* Check if opmode for regulator matches S5M8767_ENCTRL_USE_GPIO */
+        for (i = 0; i < s5m8767->num_regulators; i++) {
+                const struct sec_opmode_data *opmode = &s5m8767->opmode[i];
+                if (opmode->id == rdata->id) {
+                        mode = s5m8767_opmode_reg[rdata->id][opmode->mode];
+                        break;
+                }
+        }
+        if (mode != S5M8767_ENCTRL_USE_GPIO) {
+                dev_warn(s5m8767->dev,
+                                "ext-control for %s: mismatched op_mode (%x), ignoring\n",
+                                rdata->reg_node->name, mode);
+                return;
+        }
+
+        if (!gpio_is_valid(rdata->ext_control_gpio)) {
+                dev_warn(s5m8767->dev,
+                                "ext-control for %s: GPIO not valid, ignoring\n",
+                                rdata->reg_node->name);
+                return;
+        }
+
+        config->ena_gpio = rdata->ext_control_gpio;
+        config->ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
+}
+
+/*
+ * Turn on GPIO control over BUCK9.
+ */
+static int s5m8767_enable_ext_control(struct s5m8767_info *s5m8767,
+                struct regulator_dev *rdev)
+{
+        int ret, reg, enable_ctrl;
+
+        if (rdev_get_id(rdev) != S5M8767_BUCK9)
+                return -EINVAL;
+
+        ret = s5m8767_get_register(rdev, &reg, &enable_ctrl);
+        if (ret)
+                return ret;
+
+        return regmap_update_bits(s5m8767->iodev->regmap_pmic,
+                        reg, S5M8767_ENCTRL_MASK,
+                        S5M8767_ENCTRL_USE_GPIO << S5M8767_ENCTRL_SHIFT);
+}
+
+
 #ifdef CONFIG_OF
 static int s5m8767_pmic_dt_parse_dvs_gpio(struct sec_pmic_dev *iodev,
                         struct sec_platform_data *pdata,
@@ -520,6 +576,16 @@ static int s5m8767_pmic_dt_parse_ds_gpio(struct sec_pmic_dev *iodev,
         return 0;
 }
 
+static void s5m8767_pmic_dt_parse_ext_control_gpio(struct sec_pmic_dev *iodev,
+                struct sec_regulator_data *rdata,
+                struct device_node *reg_np)
+{
+        rdata->ext_control_gpio = of_get_named_gpio(reg_np,
+                        "s5m8767,pmic-ext-control-gpios", 0);
+        if (!gpio_is_valid(rdata->ext_control_gpio))
+                rdata->ext_control_gpio = 0;
+}
+
 static int s5m8767_pmic_dt_parse_pdata(struct platform_device *pdev,
                                         struct sec_platform_data *pdata)
 {
@@ -574,6 +640,8 @@ static int s5m8767_pmic_dt_parse_pdata(struct platform_device *pdev,
                         continue;
                 }
 
+                s5m8767_pmic_dt_parse_ext_control_gpio(iodev, rdata, reg_np);
+
                 rdata->id = i;
                 rdata->initdata = of_get_regulator_init_data(
                                                 &pdev->dev, reg_np);
@@ -940,6 +1008,9 @@ static int s5m8767_pmic_probe(struct platform_device *pdev)
                 config.driver_data = s5m8767;
                 config.regmap = iodev->regmap_pmic;
                 config.of_node = pdata->regulators[i].reg_node;
+                if (pdata->regulators[i].ext_control_gpio)
+                        s5m8767_regulator_config_ext_control(s5m8767,
+                                        &pdata->regulators[i], &config);
 
                 rdev[i] = devm_regulator_register(&pdev->dev, &regulators[id],
                                                   &config);
@@ -949,6 +1020,16 @@ static int s5m8767_pmic_probe(struct platform_device *pdev)
                                         id);
                         return ret;
                 }
+
+                if (pdata->regulators[i].ext_control_gpio) {
+                        ret = s5m8767_enable_ext_control(s5m8767, rdev[i]);
+                        if (ret < 0) {
+                                dev_err(s5m8767->dev,
+                                                "failed to enable gpio control over %s: %d\n",
+                                                rdev[i]->desc->name, ret);
+                                return ret;
+                        }
+                }
         }
 
         return 0;