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
pwm_request(int pwm_id,const char * label)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
pwm_free(struct pwm_device * pwm)55 void pwm_free(struct pwm_device *pwm)
56 {
57 peripheral_free(pwm->pin);
58 kfree(pwm);
59 }
60 EXPORT_SYMBOL(pwm_free);
61
pwm_config(struct pwm_device * pwm,int duty_ns,int period_ns)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
pwm_enable(struct pwm_device * pwm)89 int pwm_enable(struct pwm_device *pwm)
90 {
91 enable_gptimer(pwm->id);
92 return 0;
93 }
94 EXPORT_SYMBOL(pwm_enable);
95
pwm_disable(struct pwm_device * pwm)96 void pwm_disable(struct pwm_device *pwm)
97 {
98 disable_gptimer(pwm->id);
99 }
100 EXPORT_SYMBOL(pwm_disable);
101