xref: /openbmc/u-boot/drivers/pwm/pwm-imx-util.c (revision 9d466f2f)
1 /*
2  * (C) Copyright 2014
3  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
4  *
5  * Basic support for the pwm module on imx6.
6  *
7  * Based on linux:drivers/pwm/pwm-imx.c
8  * from
9  * Sascha Hauer <s.hauer@pengutronix.de>
10  *
11  * SPDX-License-Identifier:	GPL-2.0
12  */
13 
14 #include <common.h>
15 #include <div64.h>
16 #include <asm/arch/imx-regs.h>
17 
18 /* pwm_id from 0..7 */
19 struct pwm_regs *pwm_id_to_reg(int pwm_id)
20 {
21 	switch (pwm_id) {
22 	case 0:
23 		return (struct pwm_regs *)PWM1_BASE_ADDR;
24 	case 1:
25 		return (struct pwm_regs *)PWM2_BASE_ADDR;
26 #ifdef CONFIG_MX6
27 	case 2:
28 		return (struct pwm_regs *)PWM3_BASE_ADDR;
29 	case 3:
30 		return (struct pwm_regs *)PWM4_BASE_ADDR;
31 #endif
32 #ifdef CONFIG_MX6SX
33 	case 4:
34 		return (struct pwm_regs *)PWM5_BASE_ADDR;
35 	case 5:
36 		return (struct pwm_regs *)PWM6_BASE_ADDR;
37 	case 6:
38 		return (struct pwm_regs *)PWM7_BASE_ADDR;
39 	case 7:
40 		return (struct pwm_regs *)PWM8_BASE_ADDR;
41 #endif
42 	default:
43 		printf("unknown pwm_id: %d\n", pwm_id);
44 		break;
45 	}
46 	return NULL;
47 }
48 
49 int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c,
50 		      unsigned long *duty_c, unsigned long *prescale)
51 {
52 	unsigned long long c;
53 
54 	/*
55 	 * we have not yet a clock framework for imx6, so add the clock
56 	 * value here as a define. Replace it when we have the clock
57 	 * framework.
58 	 */
59 	c = CONFIG_IMX6_PWM_PER_CLK;
60 	c = c * period_ns;
61 	do_div(c, 1000000000);
62 	*period_c = c;
63 
64 	*prescale = *period_c / 0x10000 + 1;
65 
66 	*period_c /= *prescale;
67 	c = *period_c * (unsigned long long)duty_ns;
68 	do_div(c, period_ns);
69 	*duty_c = c;
70 
71 	/*
72 	 * according to imx pwm RM, the real period value should be
73 	 * PERIOD value in PWMPR plus 2.
74 	 */
75 	if (*period_c > 2)
76 		*period_c -= 2;
77 	else
78 		*period_c = 0;
79 
80 	return 0;
81 }
82