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Commit 006669ec authored by Mike Frysinger's avatar Mike Frysinger
Browse files

Blackfin: pwm: implement linux/pwm.h API 



For now, this only supports gptimers.  Support for dedicated PWM devices
as found on newer parts to come.

Signed-off-by: default avatarMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
parent e1b55965

arch/blackfin/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -953,6 +953,16 @@ config BFIN_GPTIMERS 
	  To compile this driver as a module, choose M here: the module

	  will be called gptimers.



config HAVE_PWM

	tristate "Enable PWM API support"

	depends on BFIN_GPTIMERS

	help

	  Enable support for the Pulse Width Modulation framework (as

	  found in linux/pwm.h).



	  To compile this driver as a module, choose M here: the module

	  will be called pwm.



choice

	prompt "Uncached DMA region"

	default DMA_UNCACHED_1M

arch/blackfin/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ obj-$(CONFIG_FUNCTION_TRACER) += ftrace-entry.o 
obj-$(CONFIG_FUNCTION_GRAPH_TRACER)  += ftrace.o

CFLAGS_REMOVE_ftrace.o = -pg



obj-$(CONFIG_HAVE_PWM)               += pwm.o

obj-$(CONFIG_IPIPE)                  += ipipe.o

obj-$(CONFIG_BFIN_GPTIMERS)          += gptimers.o

obj-$(CONFIG_CPLB_INFO)              += cplbinfo.o

arch/blackfin/kernel/pwm.c

0 → 100644
+100 −0
Original line number Diff line number Diff line 
/*

 * Blackfin Pulse Width Modulation (PWM) core

 *

 * Copyright (c) 2011 Analog Devices Inc.

 *

 * Licensed under the GPL-2 or later.

 */



#include <linux/module.h>

#include <linux/pwm.h>

#include <linux/slab.h>



#include <asm/gptimers.h>

#include <asm/portmux.h>



struct pwm_device {

	unsigned id;

	unsigned short pin;

};



static const unsigned short pwm_to_gptimer_per[] = {

	P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5,

	P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11,

};



struct pwm_device *pwm_request(int pwm_id, const char *label)

{

	struct pwm_device *pwm;

	int ret;



	/* XXX: pwm_id really should be unsigned */

	if (pwm_id < 0)

		return NULL;



	pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);

	if (!pwm)

		return pwm;



	pwm->id = pwm_id;

	if (pwm->id >= ARRAY_SIZE(pwm_to_gptimer_per))

		goto err;



	pwm->pin = pwm_to_gptimer_per[pwm->id];

	ret = peripheral_request(pwm->pin, label);

	if (ret)

		goto err;



	return pwm;

 err:

	kfree(pwm);

	return NULL;

}

EXPORT_SYMBOL(pwm_request);



void pwm_free(struct pwm_device *pwm)

{

	peripheral_free(pwm->pin);

	kfree(pwm);

}

EXPORT_SYMBOL(pwm_free);



int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)

{

	unsigned long period, duty;

	unsigned long long val;



	if (duty_ns < 0 || duty_ns > period_ns)

		return -EINVAL;



	val = (unsigned long long)get_sclk() * period_ns;

	do_div(val, NSEC_PER_SEC);

	period = val;



	val = (unsigned long long)period * duty_ns;

	do_div(val, period_ns);

	duty = period - val;



	if (duty >= period)

		duty = period - 1;



	set_gptimer_config(pwm->id, TIMER_MODE_PWM | TIMER_PERIOD_CNT);

	set_gptimer_pwidth(pwm->id, duty);

	set_gptimer_period(pwm->id, period);



	return 0;

}

EXPORT_SYMBOL(pwm_config);



int pwm_enable(struct pwm_device *pwm)

{

	enable_gptimer(pwm->id);

	return 0;

}

EXPORT_SYMBOL(pwm_enable);



void pwm_disable(struct pwm_device *pwm)

{

	disable_gptimer(pwm->id);

}

EXPORT_SYMBOL(pwm_disable);