phy: cpcap-usb: Add CPCAP PMIC USB support

Some Motorola phones like droid 4 use a custom CPCAP PMIC that has a
multiplexing USB PHY.

This USB PHY can operate at least in four modes using pin multiplexing
and two control GPIOS:

- Pass through companion PHY for the SoC USB PHY
- ULPI PHY for the SoC
- Pass through USB for the modem
- UART debug console for the SoC

This patch adds support for droid 4 USB PHY and debug UART modes,
support for other modes can be added later on as needed.

Both peripheral and host mode are working for the USB. The
host mode depends on the cpcap-charger driver for VBUS.

VBUS and ID pin detection are done using cpcap-adc IIO ADC
driver.

Cc: devicetree@vger.kernel.org
Cc: Marcel Partap <mpartap@gmx.net>
Cc: Michael Scott <michael.scott@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Tested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/phy-cpcap-usb.txt

+Motorola CPCAP PMIC USB PHY binding
+
+Required properties:
+compatible: Shall be either "motorola,cpcap-usb-phy" or
+	    "motorola,mapphone-cpcap-usb-phy"
+#phy-cells: Shall be 0
+interrupts: CPCAP PMIC interrupts used by the USB PHY
+interrupt-names: Interrupt names
+io-channels: IIO ADC channels used by the USB PHY
+io-channel-names: IIO ADC channel names
+vusb-supply: Regulator for the PHY
+
+Optional properties:
+pinctrl: Optional alternate pin modes for the PHY
+pinctrl-names: Names for optional pin modes
+mode-gpios: Optional GPIOs for configuring alternate modes
+
+Example:
+cpcap_usb2_phy: phy {
+	compatible = "motorola,mapphone-cpcap-usb-phy";
+	pinctrl-0 = <&usb_gpio_mux_sel1 &usb_gpio_mux_sel2>;
+	pinctrl-1 = <&usb_ulpi_pins>;
+	pinctrl-2 = <&usb_utmi_pins>;
+	pinctrl-3 = <&uart3_pins>;
+	pinctrl-names = "default", "ulpi", "utmi", "uart";
+	#phy-cells = <0>;
+	interrupts-extended = <
+		&cpcap 15 0 &cpcap 14 0 &cpcap 28 0 &cpcap 19 0
+		&cpcap 18 0 &cpcap 17 0 &cpcap 16 0 &cpcap 49 0
+		&cpcap 48 1
+	>;
+	interrupt-names =
+		"id_ground", "id_float", "se0conn", "vbusvld",
+		"sessvld", "sessend", "se1", "dm", "dp";
+	mode-gpios = <&gpio2 28 GPIO_ACTIVE_HIGH
+		      &gpio1 0 GPIO_ACTIVE_HIGH>;
+	io-channels = <&cpcap_adc 2>, <&cpcap_adc 7>;
+	io-channel-names = "vbus", "id";
+	vusb-supply = <&vusb>;
+};

drivers/phy/Kconfig

@@ -53,6 +53,7 @@ source "drivers/phy/amlogic/Kconfig"
 source "drivers/phy/broadcom/Kconfig"
 source "drivers/phy/hisilicon/Kconfig"
 source "drivers/phy/marvell/Kconfig"
+source "drivers/phy/motorola/Kconfig"
 source "drivers/phy/qualcomm/Kconfig"
 source "drivers/phy/renesas/Kconfig"
 source "drivers/phy/rockchip/Kconfig"

drivers/phy/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_ARCH_TEGRA)		+= tegra/
 obj-y					+= broadcom/	\
 					   hisilicon/	\
 					   marvell/	\
+					   motorola/	\
 					   qualcomm/	\
 					   samsung/	\
 					   st/		\

drivers/phy/motorola/Kconfig

+#
+# Phy drivers for Motorola devices
+#
+config PHY_CPCAP_USB
+	tristate "CPCAP PMIC USB PHY driver"
+	depends on USB_SUPPORT && IIO
+	select GENERIC_PHY
+	select USB_PHY
+	help
+	  Enable this for USB to work on Motorola phones and tablets
+	  such as Droid 4.

drivers/phy/motorola/Makefile

+#
+# Makefile for the phy drivers.
+#
+
+obj-$(CONFIG_PHY_CPCAP_USB)		+= phy-cpcap-usb.o