greybus: add pwm protocol driver

Add a PWM driver that implements the Greybus PWM protocol.
Signed-off-by: Matt Porter <mporter@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/Makefile

@@ -11,6 +11,7 @@ greybus-y :=	core.o		\
 		operation.o	\
 		i2c-gb.o	\
 		gpio-gb.o	\
+		pwm-gb.o	\
 		sdio-gb.o	\
 		uart-gb.o	\
 		battery-gb.o

drivers/staging/greybus/greybus_manifest.h

@@ -32,6 +32,7 @@ enum greybus_protocol {
 	GREYBUS_PROTOCOL_HID		= 0x05,
 	GREYBUS_PROTOCOL_SDIO		= 0x06,
 	GREYBUS_PROTOCOL_BATTERY	= 0x08,
+	GREYBUS_PROTOCOL_PWM		= 0x09,
 	GREYBUS_PROTOCOL_LED		= 0x0e,
 		/* ... */
 	GREYBUS_PROTOCOL_VENDOR		= 0xff,

drivers/staging/greybus/protocol.c

@@ -177,6 +177,10 @@ bool gb_protocol_init(void)
 		pr_err("error initializing i2c protocol\n");
 		ret = false;
 	}
+	if (!gb_pwm_protocol_init()) {
+		pr_err("error initializing pwm protocol\n");
+		ret = false;
+	}
 	if (!gb_uart_protocol_init()) {
 		pr_err("error initializing uart protocol\n");
 		ret = false;

drivers/staging/greybus/protocol.h

@@ -55,6 +55,9 @@ extern void gb_gpio_protocol_exit(void);
 extern bool gb_i2c_protocol_init(void);
 extern void gb_i2c_protocol_exit(void);
 
+extern bool gb_pwm_protocol_init(void);
+extern void gb_pwm_protocol_exit(void);
+
 extern bool gb_uart_protocol_init(void);
 extern void gb_uart_protocol_exit(void);