[PATCH 12/13] extcon: intel-cht-wc: Check new "intel,cht-wc-setup" device-property

[Hans de Goede <hdegoede@redhat.com>]

The CHT_WC_VBUS_GPIO_CTLO GPIO actually driving an external 5V Vboost
converter for Vbus depends on the board on which the Cherry Trail -
Whiskey Cove PMIC is actually used.

Since the information about the exact PMIC setup is necessary in other
places too, the kernel now adds a "intel,cht-wc-setup" string property
to the Whiskey Cove PMIC i2c-client based on DMI matching.

Only poke the CHT_WC_VBUS_GPIO_CTLO GPIO if this new property has the
"bq24292i,max17047,fusb302,pi3usb30532" value which indicates the Type-C
(with PD and DP-altmode) setup used on the GPD pocket and GPD win; and
on which this GPIO actually controls an external 5V Vboost converter.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/extcon/extcon-intel-cht-wc.c | 38 ++++++++++++++++------------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/drivers/extcon/extcon-intel-cht-wc.c b/drivers/extcon/extcon-intel-cht-wc.c
index 771f6f4cf92e..a7a6b43d699b 100644
--- a/drivers/extcon/extcon-intel-cht-wc.c
+++ b/drivers/extcon/extcon-intel-cht-wc.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/platform_device.h>
+#include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 
@@ -338,8 +339,8 @@ static int cht_wc_extcon_probe(struct platform_device *pdev)
 	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);
 	struct cht_wc_extcon_data *ext;
 	unsigned long mask = ~(CHT_WC_PWRSRC_VBUS | CHT_WC_PWRSRC_USBID_MASK);
-	int pwrsrc_sts, id;
-	int irq, ret;
+	int id, irq, pwrsrc_sts, ret;
+	const char *setup;
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
@@ -358,20 +359,25 @@ static int cht_wc_extcon_probe(struct platform_device *pdev)
 	if (IS_ERR(ext->edev))
 		return PTR_ERR(ext->edev);
 
-	/*
-	 * When a host-cable is detected the BIOS enables an external 5v boost
-	 * converter to power connected devices there are 2 problems with this:
-	 * 1) This gets seen by the external battery charger as a valid Vbus
-	 *    supply and it then tries to feed Vsys from this creating a
-	 *    feedback loop which causes aprox. 300 mA extra battery drain
-	 *    (and unless we drive the external-charger-disable pin high it
-	 *    also tries to charge the battery causing even more feedback).
-	 * 2) This gets seen by the pwrsrc block as a SDP USB Vbus supply
-	 * Since the external battery charger has its own 5v boost converter
-	 * which does not have these issues, we simply turn the separate
-	 * external 5v boost converter off and leave it off entirely.
-	 */
-	cht_wc_extcon_set_5v_boost(ext, false);
+	ret = device_property_read_string(ext->dev->parent, "intel,cht-wc-setup", &setup);
+	if (ret) {
+		dev_warn(ext->dev, "intel,cht-wc-setup not set\n");
+	} else if (!strcmp(setup, "bq24292i,max17047,fusb302,pi3usb30532")) {
+		/*
+		 * When a host-cable is detected the BIOS enables an external 5v boost
+		 * converter to power connected devices there are 2 problems with this:
+		 * 1) This gets seen by the external battery charger as a valid Vbus
+		 *    supply and it then tries to feed Vsys from this creating a
+		 *    feedback loop which causes aprox. 300 mA extra battery drain
+		 *    (and unless we drive the external-charger-disable pin high it
+		 *    also tries to charge the battery causing even more feedback).
+		 * 2) This gets seen by the pwrsrc block as a SDP USB Vbus supply
+		 * Since the external battery charger has its own 5v boost converter
+		 * which does not have these issues, we simply turn the separate
+		 * external 5v boost converter off and leave it off entirely.
+		 */
+		cht_wc_extcon_set_5v_boost(ext, false);
+	}
 
 	/* Enable sw control */
 	ret = cht_wc_extcon_sw_control(ext, true);
-- 
2.31.1