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Subject[PATCH v5 1/3] extcon: usbc-tusb320: Add support for mode setting and reset
Reset the chip and set its mode to default (maintain mode set by PORT pin)
during probe to make sure it comes up in the default state.

Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
---
Changes since v3:
- Remove unused tusb_modes.
Changes since v2:
- Read state before setting default mode, then update it again after resetting.
- Remove mode tracing from irq handler
- Add a delay after reset to handle tSOFT_RESET
Changes since v1:
- Split first patch into two patches, one adding support for mode setting and reset on TUSB320,
and the other adding support for TUSB320L.

drivers/extcon/extcon-usbc-tusb320.c | 85 ++++++++++++++++++++++++++--
1 file changed, 81 insertions(+), 4 deletions(-)

diff --git a/drivers/extcon/extcon-usbc-tusb320.c b/drivers/extcon/extcon-usbc-tusb320.c
index 805af73b4152..1ed1dfe54206 100644
--- a/drivers/extcon/extcon-usbc-tusb320.c
+++ b/drivers/extcon/extcon-usbc-tusb320.c
@@ -19,15 +19,32 @@
#define TUSB320_REG9_ATTACHED_STATE_MASK 0x3
#define TUSB320_REG9_CABLE_DIRECTION BIT(5)
#define TUSB320_REG9_INTERRUPT_STATUS BIT(4)
-#define TUSB320_ATTACHED_STATE_NONE 0x0
-#define TUSB320_ATTACHED_STATE_DFP 0x1
-#define TUSB320_ATTACHED_STATE_UFP 0x2
-#define TUSB320_ATTACHED_STATE_ACC 0x3
+
+#define TUSB320_REGA 0xa
+#define TUSB320_REGA_I2C_SOFT_RESET BIT(3)
+#define TUSB320_REGA_MODE_SELECT_SHIFT 4
+#define TUSB320_REGA_MODE_SELECT_MASK 0x3
+
+enum tusb320_attached_state {
+ TUSB320_ATTACHED_STATE_NONE,
+ TUSB320_ATTACHED_STATE_DFP,
+ TUSB320_ATTACHED_STATE_UFP,
+ TUSB320_ATTACHED_STATE_ACC,
+};
+
+enum tusb320_mode {
+ TUSB320_MODE_PORT,
+ TUSB320_MODE_UFP,
+ TUSB320_MODE_DFP,
+ TUSB320_MODE_DRP,
+};

struct tusb320_priv {
struct device *dev;
struct regmap *regmap;
struct extcon_dev *edev;
+
+ enum tusb320_attached_state state;
};

static const char * const tusb_attached_states[] = {
@@ -62,6 +79,53 @@ static int tusb320_check_signature(struct tusb320_priv *priv)
return 0;
}

+static int tusb320_set_mode(struct tusb320_priv *priv, enum tusb320_mode mode)
+{
+ int ret;
+
+ /* Mode cannot be changed while cable is attached */
+ if (priv->state != TUSB320_ATTACHED_STATE_NONE)
+ return -EBUSY;
+
+ /* Write mode */
+ ret = regmap_write_bits(priv->regmap, TUSB320_REGA,
+ TUSB320_REGA_MODE_SELECT_MASK << TUSB320_REGA_MODE_SELECT_SHIFT,
+ mode << TUSB320_REGA_MODE_SELECT_SHIFT);
+ if (ret) {
+ dev_err(priv->dev, "failed to write mode: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int tusb320_reset(struct tusb320_priv *priv)
+{
+ int ret;
+
+ /* Set mode to default (follow PORT pin) */
+ ret = tusb320_set_mode(priv, TUSB320_MODE_PORT);
+ if (ret && ret != -EBUSY) {
+ dev_err(priv->dev,
+ "failed to set mode to PORT: %d\n", ret);
+ return ret;
+ }
+
+ /* Perform soft reset */
+ ret = regmap_write_bits(priv->regmap, TUSB320_REGA,
+ TUSB320_REGA_I2C_SOFT_RESET, 1);
+ if (ret) {
+ dev_err(priv->dev,
+ "failed to write soft reset bit: %d\n", ret);
+ return ret;
+ }
+
+ /* Wait for chip to go through reset */
+ msleep(95);
+
+ return 0;
+}
+
static irqreturn_t tusb320_irq_handler(int irq, void *dev_id)
{
struct tusb320_priv *priv = dev_id;
@@ -96,6 +160,8 @@ static irqreturn_t tusb320_irq_handler(int irq, void *dev_id)
extcon_sync(priv->edev, EXTCON_USB);
extcon_sync(priv->edev, EXTCON_USB_HOST);

+ priv->state = state;
+
regmap_write(priv->regmap, TUSB320_REG9, reg);

return IRQ_HANDLED;
@@ -145,6 +211,17 @@ static int tusb320_extcon_probe(struct i2c_client *client,
/* update initial state */
tusb320_irq_handler(client->irq, priv);

+ /* Reset chip to its default state */
+ ret = tusb320_reset(priv);
+ if (ret)
+ dev_warn(priv->dev, "failed to reset chip: %d\n", ret);
+ else
+ /*
+ * State and polarity might change after a reset, so update
+ * them again and make sure the interrupt status bit is cleared.
+ */
+ tusb320_irq_handler(client->irq, priv);
+
ret = devm_request_threaded_irq(priv->dev, client->irq, NULL,
tusb320_irq_handler,
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
--
2.33.0

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