regulator: fixed: Support for open drain gpio pin
Laxman Dewangan [Wed, 7 Mar 2012 10:28:33 +0000 (15:28 +0530)]
Adding flag on fixed regulator board configuration structure
to specify whether gpio is open drain type or not.
Passing this information to gpio library when requesting
gpio so that gpio driver can set the pin state accordingly,
for open drain type:
- Pin can be set HIGH as setting as input, PULL UP on
  pin make this as HIGH.
- Pin can be set LOW as setting it as output and drive to LOW.

The non-open drain pin can be  set HIGH/LOW by setting it to
output and driving it to HIGH/LOW.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
cherry picked from mainline commit
a4d9f179cc788b7f4b735d32c2e4a3b2562e8240

Change-Id: I2ee7789db67fdeea77c0d6ac2b44876af36c803e
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-on: http://git-master/r/94150
Reviewed-by: Automatic_Commit_Validation_User

drivers/regulator/fixed.c
include/linux/regulator/fixed.h

index 2fe9d99..a3c06f6 100644 (file)
@@ -131,6 +131,7 @@ static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
        drvdata->startup_delay = config->startup_delay;
 
        if (gpio_is_valid(config->gpio)) {
+               int gpio_flag;
                drvdata->enable_high = config->enable_high;
 
                /* FIXME: Remove below print warning
@@ -148,27 +149,25 @@ static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
                        dev_warn(&pdev->dev,
                                "using GPIO 0 for regulator enable control\n");
 
-               ret = gpio_request(config->gpio, config->supply_name);
-               if (ret) {
-                       dev_err(&pdev->dev,
-                          "Could not obtain regulator enable GPIO %d: %d\n",
-                                                       config->gpio, ret);
-                       goto err_name;
-               }
-
-               /* set output direction without changing state
+               /*
+                * set output direction without changing state
                 * to prevent glitch
                 */
                drvdata->is_enabled = config->enabled_at_boot;
                ret = drvdata->is_enabled ?
                                config->enable_high : !config->enable_high;
+               gpio_flag = ret ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
+
+               if (config->gpio_is_open_drain)
+                       gpio_flag |= GPIOF_OPEN_DRAIN;
 
-               ret = gpio_direction_output(config->gpio, ret);
+               ret = gpio_request_one(config->gpio, gpio_flag,
+                                               config->supply_name);
                if (ret) {
                        dev_err(&pdev->dev,
-                          "Could not configure regulator enable GPIO %d direction: %d\n",
+                          "Could not obtain regulator enable GPIO %d: %d\n",
                                                        config->gpio, ret);
-                       goto err_gpio;
+                       goto err_name;
                }
 
        } else {
index ffd7d50..d9b3ef9 100644 (file)
@@ -26,6 +26,12 @@ struct regulator_init_data;
  * @gpio:              GPIO to use for enable control
  *                     set to -EINVAL if not used
  * @startup_delay:     Start-up time in microseconds
+ * @gpio_is_open_drain: Gpio pin is open drain or normal type.
+ *                     If it is open drain type then HIGH will be set
+ *                     through PULL-UP with setting gpio as input
+ *                     and low will be set as gpio-output with driven
+ *                     to low. For non-open-drain case, the gpio will
+ *                     will be in output and drive to low/high accordingly.
  * @enable_high:       Polarity of enable GPIO
  *                     1 = Active high, 0 = Active low
  * @enabled_at_boot:   Whether regulator has been enabled at
@@ -43,6 +49,7 @@ struct fixed_voltage_config {
        int microvolts;
        int gpio;
        unsigned startup_delay;
+       unsigned gpio_is_open_drain:1;
        unsigned enable_high:1;
        unsigned enabled_at_boot:1;
        struct regulator_init_data *init_data;