Add pwm core support

This patch adds framework support for PWM (pulse width modulation)
devices.
A new pwm can be registered from a hardware driver using
pwmchip_add(). It can then be requested from a client driver using
pwm_request(). A string is used as a unique identifier for the
pwms. It should usually be initialized by the hardware drivers
using dev_name(dev). The client API is the same as currently
in the Linux Kernel.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 63 insertions, 0 deletions

diff --git a/include/pwm.h b/include/pwm.h
new file mode 100644
index 0000000000..80f88b194d
--- /dev/null
+++ b/include/pwm.h
@@ -0,0 +1,63 @@
+#ifndef __PWM_H
+#define __PWM_H
+
+struct pwm_device;
+
+/*
+ * pwm_request - request a PWM device
+ */
+struct pwm_device *pwm_request(const char *pwmname);
+
+/*
+ * pwm_free - free a PWM device
+ */
+void pwm_free(struct pwm_device *pwm);
+
+/*
+ * pwm_config - change a PWM device configuration
+ */
+int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns);
+
+/*
+ * pwm_enable - start a PWM output toggling
+ */
+int pwm_enable(struct pwm_device *pwm);
+
+/*
+ * pwm_disable - stop a PWM output toggling
+ */
+void pwm_disable(struct pwm_device *pwm);
+
+struct pwm_chip;
+
+/**
+ * struct pwm_ops - PWM operations
+ * @request: optional hook for requesting a PWM
+ * @free: optional hook for freeing a PWM
+ * @config: configure duty cycles and period length for this PWM
+ * @enable: enable PWM output toggling
+ * @disable: disable PWM output toggling
+ */
+struct pwm_ops {
+	int (*request)(struct pwm_chip *chip);
+	void (*free)(struct pwm_chip *chip);
+	int (*config)(struct pwm_chip *chip, int duty_ns,
+						int period_ns);
+	int (*enable)(struct pwm_chip *chip);
+	void (*disable)(struct pwm_chip *chip);
+};
+
+/**
+ * struct pwm_chip - abstract a PWM
+ * @devname: unique identifier for this pwm
+ * @ops: The callbacks for this PWM
+ */
+struct pwm_chip {
+	const char		*devname;
+	struct pwm_ops		*ops;
+};
+
+int pwmchip_add(struct pwm_chip *chip);
+int pwmchip_remove(struct pwm_chip *chip);
+
+#endif /* __PWM_H */