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authorMike Frysinger <vapier@gentoo.org>2011-06-15 16:55:39 -0400
committerMike Frysinger <vapier@gentoo.org>2011-07-23 01:18:23 -0400
commit006669ec21d99e161015150ffedeeaeaad513c3b (patch)
treef248b63a06a302f8f0b038208bd34b4dfc824502 /arch/blackfin/kernel/pwm.c
parente1b55965337e2c0cd26055ce446c506448c08e6d (diff)
downloadlinux-006669ec21d99e161015150ffedeeaeaad513c3b.tar.gz
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>
Diffstat (limited to 'arch/blackfin/kernel/pwm.c')
-rw-r--r--arch/blackfin/kernel/pwm.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/pwm.c b/arch/blackfin/kernel/pwm.c
new file mode 100644
index 00000000000..33f5942733b
--- /dev/null
+++ b/arch/blackfin/kernel/pwm.c
@@ -0,0 +1,100 @@
+/*
+ * 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);