[PATCH 2/5] phy: cpcap-usb: add DCP detection and make UART idle mode optional

Handle DCP separately from USB host connections based on CPCAP charger
detection status.

Make the existing idle UART mode optional via the "enable_uart" module
parameter. When disabled, the PHY remains in its USB/charger detection
configuration while idle. This reduces power usage in idle by 25mW.

Also initialize the PHY into the baseline configuration required for
reliable charger detection during probe.

Note: Enabling UART idle mode increases idle power consumption.

Signed-off-by: Ivaylo Dimitrov <[email protected]>
---
 drivers/phy/motorola/phy-cpcap-usb.c | 235 ++++++++++++++++++++++-----
 1 file changed, 191 insertions(+), 44 deletions(-)

diff --git a/drivers/phy/motorola/phy-cpcap-usb.c b/drivers/phy/motorola/phy-cpcap-usb.c
index c6cc8fce6940..3be2b3afaaf4 100644
--- a/drivers/phy/motorola/phy-cpcap-usb.c
+++ b/drivers/phy/motorola/phy-cpcap-usb.c
@@ -111,6 +111,14 @@ enum cpcap_gpio_mode {
 	CPCAP_OTG_DM_DP,
 };
 
+enum cpcap_mode {
+	CPCAP_IDLE,
+	CPCAP_CHARGER,
+	CPCAP_USB,
+	CPCAP_USB_HOST,
+	CPCAP_DOCK,
+};
+
 struct cpcap_phy_ddata {
 	struct regmap *reg;
 	struct device *dev;
@@ -125,10 +133,13 @@ struct cpcap_phy_ddata {
 	struct iio_channel *id;
 	struct regulator *vusb;
 	atomic_t active;
-	unsigned int vbus_provider:1;
-	unsigned int docked:1;
+	enum cpcap_mode mode;
 };
 
+static bool cpcap_enable_uart;
+module_param_named(enable_uart, cpcap_enable_uart, bool, 0644);
+MODULE_PARM_DESC(enable_uart,
+		 "Enable UART on the USB connector while idle (increases power consumption)");
 static bool cpcap_usb_vbus_valid(struct cpcap_phy_ddata *ddata)
 {
 	int error, value = 0;
@@ -176,6 +187,7 @@ static int cpcap_phy_get_ints_state(struct cpcap_phy_ddata *ddata,
 
 	s->id_ground = val & BIT(15);
 	s->id_float = val & BIT(14);
+	s->chrg_det = val & BIT(13);
 	s->vbusov = val & BIT(11);
 
 	error = regmap_read(ddata->reg, CPCAP_REG_INTS2, &val);
@@ -197,8 +209,9 @@ static int cpcap_phy_get_ints_state(struct cpcap_phy_ddata *ddata,
 	return 0;
 }
 
-static int cpcap_usb_set_uart_mode(struct cpcap_phy_ddata *ddata);
+static int cpcap_usb_set_idle_mode(struct cpcap_phy_ddata *ddata);
 static int cpcap_usb_set_usb_mode(struct cpcap_phy_ddata *ddata);
+static int cpcap_usb_set_dcp_mode(struct cpcap_phy_ddata *ddata);
 
 static void cpcap_usb_try_musb_mailbox(struct cpcap_phy_ddata *ddata,
 				       enum musb_vbus_id_status status)
@@ -229,7 +242,7 @@ static void cpcap_usb_detect(struct work_struct *work)
 	vbus = cpcap_usb_vbus_valid(ddata);
 
 	/* We need to kick the VBUS as USB A-host */
-	if (s.id_ground && ddata->vbus_provider) {
+	if (s.id_ground && ddata->mode == CPCAP_USB_HOST) {
 		dev_dbg(ddata->dev, "still in USB A-host mode, kicking VBUS\n");
 
 		cpcap_usb_try_musb_mailbox(ddata, MUSB_ID_GROUND);
@@ -244,7 +257,7 @@ static void cpcap_usb_detect(struct work_struct *work)
 		return;
 	}
 
-	if (vbus && s.id_ground && ddata->docked) {
+	if (vbus && s.id_ground && ddata->mode == CPCAP_DOCK) {
 		dev_dbg(ddata->dev, "still docked as A-host, signal ID down\n");
 
 		cpcap_usb_try_musb_mailbox(ddata, MUSB_ID_GROUND);
@@ -253,10 +266,10 @@ static void cpcap_usb_detect(struct work_struct *work)
 	}
 
 	/* No VBUS needed with docks */
-	if (vbus && s.id_ground && !ddata->vbus_provider) {
+	if (vbus && s.id_ground && ddata->mode != CPCAP_USB_HOST) {
 		dev_dbg(ddata->dev, "connected to a dock\n");
 
-		ddata->docked = true;
+		ddata->mode = CPCAP_DOCK;
 
 		error = cpcap_usb_set_usb_mode(ddata);
 		if (error)
@@ -275,10 +288,10 @@ static void cpcap_usb_detect(struct work_struct *work)
 		return;
 	}
 
-	if (s.id_ground && !ddata->docked) {
+	if (s.id_ground && ddata->mode != CPCAP_DOCK) {
 		dev_dbg(ddata->dev, "id ground, USB host mode\n");
 
-		ddata->vbus_provider = true;
+		ddata->mode = CPCAP_USB_HOST;
 
 		error = cpcap_usb_set_usb_mode(ddata);
 		if (error)
@@ -296,36 +309,53 @@ static void cpcap_usb_detect(struct work_struct *work)
 		return;
 	}
 
-	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3,
-				   CPCAP_BIT_VBUSSTBY_EN |
-				   CPCAP_BIT_VBUSEN_SPI, 0);
-	if (error)
-		goto out_err;
-
 	vbus = cpcap_usb_vbus_valid(ddata);
 
-	/* Otherwise assume we're connected to a USB host */
-	if (vbus) {
-		dev_dbg(ddata->dev, "connected to USB host\n");
-		error = cpcap_usb_set_usb_mode(ddata);
+	/* Check if we're connected to a USB host */
+	if (vbus && ddata->mode != CPCAP_USB_HOST) {
+		if (!s.chrg_det || !s.sessvld || ddata->mode != CPCAP_IDLE)
+			return;
+
+		if (s.se1)
+			ddata->mode = CPCAP_CHARGER;
+		else if (!s.dm && !s.dp)
+			ddata->mode = CPCAP_USB;
+		else
+			return;
+
+		dev_dbg(ddata->dev, "connected to %s\n",
+			s.se1 ? "DCP" : "USB host");
+
+		error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3,
+					   CPCAP_BIT_VBUSSTBY_EN |
+					   CPCAP_BIT_VBUSEN_SPI, 0);
 		if (error)
 			goto out_err;
-		cpcap_usb_try_musb_mailbox(ddata, MUSB_VBUS_VALID);
+
+		if (ddata->mode == CPCAP_CHARGER)
+			error = cpcap_usb_set_dcp_mode(ddata);
+		else
+			error = cpcap_usb_set_usb_mode(ddata);
+
+		if (error)
+			goto out_err;
+
+		if (ddata->mode == CPCAP_USB)
+			cpcap_usb_try_musb_mailbox(ddata, MUSB_VBUS_VALID);
 
 		return;
 	}
 
-	ddata->vbus_provider = false;
-	ddata->docked = false;
+	if (ddata->mode == CPCAP_IDLE)
+		return;
+
+	ddata->mode = CPCAP_IDLE;
 	cpcap_usb_try_musb_mailbox(ddata, MUSB_VBUS_OFF);
 
-	/* Default to debug UART mode */
-	error = cpcap_usb_set_uart_mode(ddata);
+	error = cpcap_usb_set_idle_mode(ddata);
 	if (error)
 		goto out_err;
 
-	dev_dbg(ddata->dev, "set UART mode\n");
-
 	return;
 
 out_err:
@@ -374,7 +404,7 @@ static const char * const cpcap_phy_irqs[] = {
 	"id_ground", "id_float",
 
 	/* REG_INT1 */
-	"se0conn", "vbusvld", "sessvld", "sessend", "se1",
+	"se0conn", "vbusvld", "sessvld", "sessend", "chrg_det",
 
 	/* REG_INT_3 */
 	"dm", "dp",
@@ -412,9 +442,10 @@ static int cpcap_usb_gpio_set_mode(struct cpcap_phy_ddata *ddata,
 	return 0;
 }
 
-static int cpcap_usb_set_uart_mode(struct cpcap_phy_ddata *ddata)
+static int cpcap_usb_set_idle_mode(struct cpcap_phy_ddata *ddata)
 {
 	int sysrq, error;
+	unsigned int val;
 
 	/* Disable sysrq to prevent random sysrq events on line glitches */
 	sysrq = sysrq_mask();
@@ -426,30 +457,52 @@ static int cpcap_usb_set_uart_mode(struct cpcap_phy_ddata *ddata)
 	if (error)
 		goto out_err;
 
-	if (ddata->pins_uart) {
-		error = pinctrl_select_state(ddata->pins, ddata->pins_uart);
+	if (cpcap_enable_uart && ddata->pins_uart) {
+		error = pinctrl_select_state(ddata->pins,  ddata->pins_uart);
+		if (error)
+			goto out_err;
+	} else if (!cpcap_enable_uart && ddata->pins_ulpi) {
+		error = pinctrl_select_state(ddata->pins, ddata->pins_ulpi);
 		if (error)
 			goto out_err;
 	}
 
 	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC1,
+				   CPCAP_BIT_DP150KPU |
+				   CPCAP_BIT_DP1K5PU |
+				   CPCAP_BIT_DM1K5PU |
+				   CPCAP_BIT_DPPD |
+				   CPCAP_BIT_DMPD |
 				   CPCAP_BIT_VBUSPD,
+				   CPCAP_BIT_DP150KPU |
 				   CPCAP_BIT_VBUSPD);
 	if (error)
 		goto out_err;
 
-	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC2,
-				   0xffff, CPCAP_BIT_UARTMUX0 |
-				   CPCAP_BIT_EMUMODE0);
+	val = CPCAP_BIT_USBSUSPEND;
+
+	if (cpcap_enable_uart)
+		val |= (CPCAP_BIT_UARTMUX0 | CPCAP_BIT_EMUMODE0);
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC2, 0xffff, val);
 	if (error)
 		goto out_err;
 
-	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3, 0x7fff,
-				   CPCAP_BIT_IDPU_SPI);
+	val = CPCAP_BIT_VBUSSTBY_EN |
+	      CPCAP_BIT_VBUSPD_SPI |
+	      CPCAP_BIT_DMPD_SPI |
+	      CPCAP_BIT_DPPD_SPI |
+	      CPCAP_BIT_PU_SPI |
+	      CPCAP_BIT_IDPU_SPI |
+	      CPCAP_BIT_ULPI_SPI_SEL;
+
+	if (!cpcap_enable_uart)
+		val |= CPCAP_BIT_SUSPEND_SPI;
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3, 0x7fff, val);
 	if (error)
 		goto out_err;
 
-	/* Enable UART mode */
 	error = cpcap_usb_gpio_set_mode(ddata, CPCAP_DM_DP);
 	if (error)
 		goto out_err;
@@ -457,6 +510,8 @@ static int cpcap_usb_set_uart_mode(struct cpcap_phy_ddata *ddata)
 	if (sysrq & 1)
 		sysrq_toggle_support(sysrq);
 
+	dev_dbg(ddata->dev, "set %s mode\n", cpcap_enable_uart ? "UART" : "IDLE");
+
 	return 0;
 
 out_err:
@@ -517,6 +572,42 @@ static int cpcap_usb_set_usb_mode(struct cpcap_phy_ddata *ddata)
 	return error;
 }
 
+static int cpcap_usb_set_dcp_mode(struct cpcap_phy_ddata *ddata)
+{
+	int error = 0;
+
+	/* Disable lines to prevent glitches from waking up mdm6600 */
+	error = cpcap_usb_gpio_set_mode(ddata, CPCAP_UNKNOWN_DISABLED);
+	if (error)
+		return error;
+
+	if (ddata->pins_ulpi) {
+		error = pinctrl_select_state(ddata->pins, ddata->pins_ulpi);
+		if (error) {
+			dev_err(ddata->dev, "could not set usb mode: %i\n",
+				error);
+
+			return error;
+		}
+	}
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3,
+				   CPCAP_BIT_SUSPEND_SPI, 0);
+	if (error)
+		goto out_err;
+
+	error = cpcap_usb_gpio_set_mode(ddata, CPCAP_DM_DP);
+	if (error)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	dev_err(ddata->dev, "%s failed with %i\n", __func__, error);
+
+	return error;
+}
+
 static int cpcap_usb_init_optional_pins(struct cpcap_phy_ddata *ddata)
 {
 	ddata->pins = devm_pinctrl_get(ddata->dev);
@@ -546,9 +637,6 @@ static int cpcap_usb_init_optional_pins(struct cpcap_phy_ddata *ddata)
 		ddata->pins_uart = NULL;
 	}
 
-	if (ddata->pins_uart)
-		return pinctrl_select_state(ddata->pins, ddata->pins_uart);
-
 	return 0;
 }
 
@@ -601,6 +689,65 @@ static int cpcap_usb_init_iio(struct cpcap_phy_ddata *ddata)
 	return error;
 }
 
+static int cpcap_usb_init_usb(struct cpcap_phy_ddata *ddata)
+{
+	struct cpcap_usb_ints_state s;
+	int error;
+	int mask;
+
+	error = cpcap_phy_get_ints_state(ddata, &s);
+	if (error)
+		return error;
+
+	error = cpcap_usb_gpio_set_mode(ddata, CPCAP_UNKNOWN_DISABLED);
+	if (error)
+		return error;
+
+	if (ddata->pins_ulpi) {
+		error = pinctrl_select_state(ddata->pins, ddata->pins_ulpi);
+		if (error)
+			return error;
+	}
+
+	/*
+	 * Do not touch DM/DP PD as this will break charger detection if charger
+	 * is connected before we detect it.
+	 */
+	if (s.se1) {
+		mask = CPCAP_BIT_VBUSEN_SPI | CPCAP_BIT_VBUSPU_SPI |
+		       CPCAP_BIT_SUSPEND_SPI | CPCAP_BIT_ULPI_SPI_SEL;
+	} else {
+		mask = CPCAP_BIT_VBUSEN_SPI | CPCAP_BIT_VBUSPU_SPI |
+		       CPCAP_BIT_DMPD_SPI | CPCAP_BIT_DPPD_SPI |
+		       CPCAP_BIT_SUSPEND_SPI | CPCAP_BIT_PU_SPI |
+		       CPCAP_BIT_ULPI_SPI_SEL;
+	}
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC3, mask,
+				   CPCAP_BIT_ULPI_SPI_SEL);
+	if (error)
+		return error;
+
+	/*
+	 * Configure safe DP/DM termination state.
+	 *
+	 * Vendor kernel uses:
+	 *   DP150KPU = enabled
+	 *   all USB pullups/pulldowns = disabled
+	 */
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_USBC1,
+				   CPCAP_BIT_DP150KPU |
+				   CPCAP_BIT_DP1K5PU |
+				   CPCAP_BIT_DM1K5PU |
+				   CPCAP_BIT_DPPD |
+				   CPCAP_BIT_DMPD,
+				   CPCAP_BIT_DP150KPU);
+	if (error)
+		return error;
+
+	return cpcap_usb_gpio_set_mode(ddata, CPCAP_DM_DP);
+}
+
 #ifdef CONFIG_OF
 static const struct of_device_id cpcap_usb_phy_id_table[] = {
 	{
@@ -678,6 +825,10 @@ static int cpcap_usb_phy_probe(struct platform_device *pdev)
 	if (error)
 		goto out_reg_disable;
 
+	error = cpcap_usb_init_usb(ddata);
+	if (error)
+		goto out_reg_disable;
+
 	error = cpcap_usb_init_interrupts(pdev, ddata);
 	if (error)
 		goto out_reg_disable;
@@ -697,13 +848,9 @@ static int cpcap_usb_phy_probe(struct platform_device *pdev)
 static void cpcap_usb_phy_remove(struct platform_device *pdev)
 {
 	struct cpcap_phy_ddata *ddata = platform_get_drvdata(pdev);
-	int error;
 
 	atomic_set(&ddata->active, 0);
-	error = cpcap_usb_set_uart_mode(ddata);
-	if (error)
-		dev_err(ddata->dev, "could not set UART mode\n");
-
+	cpcap_usb_set_idle_mode(ddata);
 	cpcap_usb_try_musb_mailbox(ddata, MUSB_VBUS_OFF);
 
 	usb_remove_phy(&ddata->phy);
-- 
2.25.1