dm: pwm: Add a PWM uclass

Add a uclass that supports Pulse Width Modulation (PWM) devices. It
provides methods to enable/disable and configure the device.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/Kconfig

@@ -46,6 +46,8 @@ source "drivers/pinctrl/Kconfig"
 
 source "drivers/power/Kconfig"
 
+source "drivers/pwm/Kconfig"
+
 source "drivers/ram/Kconfig"
 
 source "drivers/remoteproc/Kconfig"

drivers/pwm/Kconfig

@@ -0,0 +1,10 @@
+config DM_PWM
+	bool "Enable support for pulse-width modulation devices (PWM)"
+	depends on DM
+	help
+	  A pulse-width modulator emits a pulse of varying width and provides
+	  control over the duty cycle (high and low time) of the signal. This
+	  is often used to control a voltage level. The more time the PWM
+	  spends in the 'high' state, the higher the voltage. The PWM's
+	  frequency/period can be controlled along with the proportion of that
+	  time that the signal is high.

drivers/pwm/Makefile

@@ -10,4 +10,5 @@
 
 #ccflags-y += -DDEBUG
 
+obj-$(CONFIG_DM_PWM) += pwm-uclass.o
 obj-$(CONFIG_PWM_IMX) += pwm-imx.o pwm-imx-util.o

drivers/pwm/pwm-uclass.c

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <pwm.h>
+
+int pwm_set_config(struct udevice *dev, uint channel, uint period_ns,
+		   uint duty_ns)
+{
+	struct pwm_ops *ops = pwm_get_ops(dev);
+
+	if (!ops->set_config)
+		return -ENOSYS;
+
+	return ops->set_config(dev, channel, period_ns, duty_ns);
+}
+
+int pwm_set_enable(struct udevice *dev, uint channel, bool enable)
+{
+	struct pwm_ops *ops = pwm_get_ops(dev);
+
+	if (!ops->set_enable)
+		return -ENOSYS;
+
+	return ops->set_enable(dev, channel, enable);
+}
+
+UCLASS_DRIVER(pwm) = {
+	.id		= UCLASS_PWM,
+	.name		= "pwm",
+};

include/dm/uclass-id.h

@@ -51,6 +51,7 @@ enum uclass_id {
 	UCLASS_PINCTRL,		/* Pinctrl (pin muxing/configuration) device */
 	UCLASS_PINCONFIG,	/* Pin configuration node device */
 	UCLASS_PMIC,		/* PMIC I/O device */
+	UCLASS_PWM,		/* Pulse-width modulator */
 	UCLASS_PWRSEQ,		/* Power sequence device */
 	UCLASS_REGULATOR,	/* Regulator device */
 	UCLASS_RESET,		/* Reset device */

include/pwm.h

@@ -1,6 +1,7 @@
 /*
  * header file for pwm driver.
  *
+ * Copyright 2016 Google Inc.
  * Copyright (c) 2011 samsung electronics
  * Donghwa Lee <dh09.lee@samsung.com>
  *
@@ -10,9 +11,61 @@
 #ifndef _pwm_h_
 #define _pwm_h_
 
+/* struct pwm_ops: Operations for the PWM uclass */
+struct pwm_ops {
+	/**
+	 * set_config() - Set the PWM configuration
+	 *
+	 * @dev:	PWM device to update
+	 * @channel:	PWM channel to update
+	 * @period_ns:	PWM period in nanoseconds
+	 * @duty_ns:	PWM duty period in nanoseconds
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*set_config)(struct udevice *dev, uint channel, uint period_ns,
+			  uint duty_ns);
+
+	/**
+	 * set_enable() - Enable or disable the PWM
+	 *
+	 * @dev:	PWM device to update
+	 * @channel:	PWM channel to update
+	 * @enable:	true to enable, false to disable
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*set_enable)(struct udevice *dev, uint channel, bool enable);
+};
+
+#define pwm_get_ops(dev)	((struct pwm_ops *)(dev)->driver->ops)
+
+/**
+ * pwm_set_config() - Set the PWM configuration
+ *
+ * @dev:	PWM device to update
+ * @channel:	PWM channel to update
+ * @period_ns:	PWM period in nanoseconds
+ * @duty_ns:	PWM duty period in nanoseconds
+ * @return 0 if OK, -ve on error
+ */
+int pwm_set_config(struct udevice *dev, uint channel, uint period_ns,
+		   uint duty_ns);
+
+/**
+ * pwm_set_enable() - Enable or disable the PWM
+ *
+ * @dev:	PWM device to update
+ * @channel:	PWM channel to update
+ * @enable:	true to enable, false to disable
+ * @return 0 if OK, -ve on error
+ */
+int pwm_set_enable(struct udevice *dev, uint channel, bool enable);
+
+/* Legacy interface */
+#ifndef CONFIG_DM_PWM
 int	pwm_init		(int pwm_id, int div, int invert);
 int	pwm_config		(int pwm_id, int duty_ns, int period_ns);
 int	pwm_enable		(int pwm_id);
 void	pwm_disable		(int pwm_id);
+#endif
 
 #endif /* _pwm_h_ */