[ARM] pxa: Add bare bones PWM API

Signed-off-by: Russell King <[e-mail]>

arch/arm/Kconfig

···
 	  Europe.  There is an ARM Linux project with a web page at
 	  <http://www.arm.linux.org.uk/>.
 
+config HAVE_PWM
+	bool
+
 config SYS_SUPPORTS_APM_EMULATION
 	bool
 

include/linux/pwm.h

···
+#ifndef __LINUX_PWM_H
+#define __LINUX_PWM_H
+
+struct pwm_device;
+
+/*
+ * pwm_request - request a PWM device
+ */
+struct pwm_device *pwm_request(int pwm_id, const char *label);
+
+/*
+ * 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);
+
+#endif /* __ASM_ARCH_PWM_H */