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: Michael Hennerich <michael.hennerich@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>

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: Michael Hennerich <michael.hennerich@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Mike Frysinger
1 parent e1b5596533
Showing 3 changed files with 111 additions and 0 deletions Side-by-side Diff
arch/blackfin/Kconfig
arch/blackfin/kernel/Makefile
arch/blackfin/kernel/pwm.c
@@ -953,6 +953,16 @@
 	  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
@@ -21,6 +21,7 @@
 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
+/*
+ * 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);
...	...	@@ -953,6 +953,16 @@
953	953	To compile this driver as a module, choose M here: the module
954	954	will be called gptimers.
955	955
	956	+config HAVE_PWM
	957	+ tristate "Enable PWM API support"
	958	+ depends on BFIN_GPTIMERS
	959	+ help
	960	+ Enable support for the Pulse Width Modulation framework (as
	961	+ found in linux/pwm.h).
	962	+
	963	+ To compile this driver as a module, choose M here: the module
	964	+ will be called pwm.
	965	+
956	966	choice
957	967	prompt "Uncached DMA region"
958	968	default DMA_UNCACHED_1M
...	...	@@ -21,6 +21,7 @@
21	21	obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
22	22	CFLAGS_REMOVE_ftrace.o = -pg
23	23
	24	+obj-$(CONFIG_HAVE_PWM) += pwm.o
24	25	obj-$(CONFIG_IPIPE) += ipipe.o
25	26	obj-$(CONFIG_BFIN_GPTIMERS) += gptimers.o
26	27	obj-$(CONFIG_CPLB_INFO) += cplbinfo.o
	1	+/*
	2	+ * Blackfin Pulse Width Modulation (PWM) core
	3	+ *
	4	+ * Copyright (c) 2011 Analog Devices Inc.
	5	+ *
	6	+ * Licensed under the GPL-2 or later.
	7	+ */
	8	+
	9	+#include <linux/module.h>
	10	+#include <linux/pwm.h>
	11	+#include <linux/slab.h>
	12	+
	13	+#include <asm/gptimers.h>
	14	+#include <asm/portmux.h>
	15	+
	16	+struct pwm_device {
	17	+ unsigned id;
	18	+ unsigned short pin;
	19	+};
	20	+
	21	+static const unsigned short pwm_to_gptimer_per[] = {
	22	+ P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5,
	23	+ P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11,
	24	+};
	25	+
	26	+struct pwm_device pwm_request(int pwm_id, const char label)
	27	+{
	28	+ struct pwm_device *pwm;
	29	+ int ret;
	30	+
	31	+ /* XXX: pwm_id really should be unsigned */
	32	+ if (pwm_id < 0)
	33	+ return NULL;
	34	+
	35	+ pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
	36	+ if (!pwm)
	37	+ return pwm;
	38	+
	39	+ pwm->id = pwm_id;
	40	+ if (pwm->id >= ARRAY_SIZE(pwm_to_gptimer_per))
	41	+ goto err;
	42	+
	43	+ pwm->pin = pwm_to_gptimer_per[pwm->id];
	44	+ ret = peripheral_request(pwm->pin, label);
	45	+ if (ret)
	46	+ goto err;
	47	+
	48	+ return pwm;
	49	+ err:
	50	+ kfree(pwm);
	51	+ return NULL;
	52	+}
	53	+EXPORT_SYMBOL(pwm_request);
	54	+
	55	+void pwm_free(struct pwm_device *pwm)
	56	+{
	57	+ peripheral_free(pwm->pin);
	58	+ kfree(pwm);
	59	+}
	60	+EXPORT_SYMBOL(pwm_free);
	61	+
	62	+int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
	63	+{
	64	+ unsigned long period, duty;
	65	+ unsigned long long val;
	66	+
	67	+ if (duty_ns < 0 \|\| duty_ns > period_ns)
	68	+ return -EINVAL;
	69	+
	70	+ val = (unsigned long long)get_sclk() * period_ns;
	71	+ do_div(val, NSEC_PER_SEC);
	72	+ period = val;
	73	+
	74	+ val = (unsigned long long)period * duty_ns;
	75	+ do_div(val, period_ns);
	76	+ duty = period - val;
	77	+
	78	+ if (duty >= period)
	79	+ duty = period - 1;
	80	+
	81	+ set_gptimer_config(pwm->id, TIMER_MODE_PWM \| TIMER_PERIOD_CNT);
	82	+ set_gptimer_pwidth(pwm->id, duty);
	83	+ set_gptimer_period(pwm->id, period);
	84	+
	85	+ return 0;
	86	+}
	87	+EXPORT_SYMBOL(pwm_config);
	88	+
	89	+int pwm_enable(struct pwm_device *pwm)
	90	+{
	91	+ enable_gptimer(pwm->id);
	92	+ return 0;
	93	+}
	94	+EXPORT_SYMBOL(pwm_enable);
	95	+
	96	+void pwm_disable(struct pwm_device *pwm)
	97	+{
	98	+ disable_gptimer(pwm->id);
	99	+}
	100	+EXPORT_SYMBOL(pwm_disable);