006669ec21
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>
100 lines
1.9 KiB
C
100 lines
1.9 KiB
C
/*
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* Blackfin Pulse Width Modulation (PWM) core
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*
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* Copyright (c) 2011 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <linux/module.h>
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#include <linux/pwm.h>
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#include <linux/slab.h>
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#include <asm/gptimers.h>
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#include <asm/portmux.h>
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struct pwm_device {
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unsigned id;
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unsigned short pin;
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};
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static const unsigned short pwm_to_gptimer_per[] = {
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P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5,
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P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11,
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};
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struct pwm_device *pwm_request(int pwm_id, const char *label)
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{
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struct pwm_device *pwm;
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int ret;
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/* XXX: pwm_id really should be unsigned */
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if (pwm_id < 0)
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return NULL;
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pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
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if (!pwm)
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return pwm;
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pwm->id = pwm_id;
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if (pwm->id >= ARRAY_SIZE(pwm_to_gptimer_per))
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goto err;
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pwm->pin = pwm_to_gptimer_per[pwm->id];
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ret = peripheral_request(pwm->pin, label);
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if (ret)
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goto err;
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return pwm;
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err:
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kfree(pwm);
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return NULL;
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}
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EXPORT_SYMBOL(pwm_request);
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void pwm_free(struct pwm_device *pwm)
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{
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peripheral_free(pwm->pin);
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kfree(pwm);
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}
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EXPORT_SYMBOL(pwm_free);
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int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
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{
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unsigned long period, duty;
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unsigned long long val;
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if (duty_ns < 0 || duty_ns > period_ns)
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return -EINVAL;
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val = (unsigned long long)get_sclk() * period_ns;
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do_div(val, NSEC_PER_SEC);
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period = val;
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val = (unsigned long long)period * duty_ns;
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do_div(val, period_ns);
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duty = period - val;
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if (duty >= period)
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duty = period - 1;
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set_gptimer_config(pwm->id, TIMER_MODE_PWM | TIMER_PERIOD_CNT);
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set_gptimer_pwidth(pwm->id, duty);
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set_gptimer_period(pwm->id, period);
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return 0;
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}
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EXPORT_SYMBOL(pwm_config);
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int pwm_enable(struct pwm_device *pwm)
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{
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enable_gptimer(pwm->id);
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return 0;
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}
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EXPORT_SYMBOL(pwm_enable);
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void pwm_disable(struct pwm_device *pwm)
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{
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disable_gptimer(pwm->id);
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}
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EXPORT_SYMBOL(pwm_disable);
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