extcon: arizona: Support direct microphone measurement via HPDET

With some GPIO control it is possible to detect microphones in a wider
range of configurations by directly measuring the microphone impedance
when the HPDET method cannot distinguish between the behaviour of the
two grounds. Allow a GPIO to be provided in platform data and use it to
implement this behaviour.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>

1 files changed, 45 insertions, 5 deletions

diff --git a/drivers/extcon/extcon-arizona.c b/drivers/extcon/extcon-arizona.c
index ba9525ee4706..de141f72c8e5 100644
--- a/drivers/extcon/extcon-arizona.c
+++ b/drivers/extcon/extcon-arizona.c
@@ -56,7 +56,7 @@ struct arizona_extcon_info {
         bool hpdet_active;
 
         int num_hpdet_res;
-        unsigned int hpdet_res[2];
+        unsigned int hpdet_res[3];
 
         bool mic;
         bool detecting;
@@ -313,6 +313,7 @@ static int arizona_hpdet_read(struct arizona_extcon_info *info)
 static int arizona_hpdet_do_id(struct arizona_extcon_info *info, int *reading)
 {
         struct arizona *arizona = info->arizona;
+        int id_gpio = arizona->pdata.hpdet_id_gpio;
         int ret;
 
         /*
@@ -338,9 +339,27 @@ static int arizona_hpdet_do_id(struct arizona_extcon_info *info, int *reading)
                                            ARIZONA_ACCESSORY_DETECT_MODE_1,
                                            ARIZONA_ACCDET_SRC,
                                            ~info->micd_modes[0].src);
+
                         regmap_update_bits(arizona->regmap,
                                            ARIZONA_HEADPHONE_DETECT_1,
-                                           ARIZONA_HP_POLL, 0);
+                                           ARIZONA_HP_POLL, ARIZONA_HP_POLL);
+                        return -EAGAIN;
+                }
+
+                /* Only check the mic directly if we didn't already ID it */
+                if (id_gpio && info->num_hpdet_res == 2 &&
+                    !((info->hpdet_res[0] > info->hpdet_res[1] * 2))) {
+                        dev_dbg(arizona->dev, "Measuring mic\n");
+
+                        regmap_update_bits(arizona->regmap,
+                                           ARIZONA_ACCESSORY_DETECT_MODE_1,
+                                           ARIZONA_ACCDET_MODE_MASK |
+                                           ARIZONA_ACCDET_SRC,
+                                           ARIZONA_ACCDET_MODE_HPR |
+                                           info->micd_modes[0].src);
+
+                        gpio_set_value_cansleep(id_gpio, 1);
+
                         regmap_update_bits(arizona->regmap,
                                            ARIZONA_HEADPHONE_DETECT_1,
                                            ARIZONA_HP_POLL, ARIZONA_HP_POLL);
@@ -348,10 +367,16 @@ static int arizona_hpdet_do_id(struct arizona_extcon_info *info, int *reading)
                 }
 
                 /* OK, got both.  Now, compare... */
-                dev_dbg(arizona->dev, "HPDET measured %d %d\n",
-                        info->hpdet_res[0], info->hpdet_res[1]);
+                dev_dbg(arizona->dev, "HPDET measured %d %d %d\n",
+                        info->hpdet_res[0], info->hpdet_res[1],
+                        info->hpdet_res[2]);
 
-                if (info->hpdet_res[0] > info->hpdet_res[1] * 2) {
+                /*
+                 * Either the two grounds measure differently or we
+                 * measure the mic as high impedance.
+                 */
+                if ((info->hpdet_res[0] > info->hpdet_res[1] * 2) ||
+                    (id_gpio && info->hpdet_res[2] > 10)) {
                         dev_dbg(arizona->dev, "Detected mic\n");
                         info->mic = true;
                         ret = extcon_set_cable_state_(&info->edev,
@@ -382,6 +407,7 @@ static irqreturn_t arizona_hpdet_irq(int irq, void *data)
 {
         struct arizona_extcon_info *info = data;
         struct arizona *arizona = info->arizona;
+        int id_gpio = arizona->pdata.hpdet_id_gpio;
         int report = ARIZONA_CABLE_HEADPHONE;
         int ret, reading;
 
@@ -446,6 +472,8 @@ static irqreturn_t arizona_hpdet_irq(int irq, void *data)
                 dev_warn(arizona->dev, "Failed to undo magic: %d\n", ret);
 
 done:
+        if (id_gpio)
+                gpio_set_value_cansleep(id_gpio, 0);
 
         /* Revert back to MICDET mode */
         regmap_update_bits(arizona->regmap,
@@ -854,6 +882,18 @@ static int arizona_extcon_probe(struct platform_device *pdev)
                 }
         }
 
+        if (arizona->pdata.hpdet_id_gpio > 0) {
+                ret = devm_gpio_request_one(&pdev->dev,
+                                            arizona->pdata.hpdet_id_gpio,
+                                            GPIOF_OUT_INIT_LOW,
+                                            "HPDET");
+                if (ret != 0) {
+                        dev_err(arizona->dev, "Failed to request GPIO%d: %d\n",
+                                arizona->pdata.hpdet_id_gpio, ret);
+                        goto err_register;
+                }
+        }
+
         if (arizona->pdata.micd_bias_start_time)
                 regmap_update_bits(arizona->regmap, ARIZONA_MIC_DETECT_1,
                                    ARIZONA_MICD_BIAS_STARTTIME_MASK,