pwm-imx-util.c
1.45 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
/*
* (C) Copyright 2014
* Heiko Schocher, DENX Software Engineering, hs@denx.de.
*
* Basic support for the pwm modul on imx6.
*
* Based on linux:drivers/pwm/pwm-imx.c
* from
* Sascha Hauer <s.hauer@pengutronix.de>
*
* SPDX-License-Identifier: GPL-2.0
*/
#include <common.h>
#include <div64.h>
#include <asm/arch/imx-regs.h>
/* pwm_id from 0..3 */
struct pwm_regs *pwm_id_to_reg(int pwm_id)
{
switch (pwm_id) {
case 0:
return (struct pwm_regs *)PWM1_BASE_ADDR;
break;
case 1:
return (struct pwm_regs *)PWM2_BASE_ADDR;
break;
case 2:
return (struct pwm_regs *)PWM3_BASE_ADDR;
break;
case 3:
return (struct pwm_regs *)PWM4_BASE_ADDR;
break;
default:
printf("unknown pwm_id: %d\n", pwm_id);
break;
}
return NULL;
}
int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c,
unsigned long *duty_c, unsigned long *prescale)
{
unsigned long long c;
/*
* we have not yet a clock framework for imx6, so add the clock
* value here as a define. Replace it when we have the clock
* framework.
*/
c = CONFIG_IMX6_PWM_PER_CLK;
c = c * period_ns;
do_div(c, 1000000000);
*period_c = c;
*prescale = *period_c / 0x10000 + 1;
*period_c /= *prescale;
c = (unsigned long long)(*period_c * duty_ns);
do_div(c, period_ns);
*duty_c = c;
/*
* according to imx pwm RM, the real period value should be
* PERIOD value in PWMPR plus 2.
*/
if (*period_c > 2)
*period_c -= 2;
else
*period_c = 0;
return 0;
}