| Heiko Schocher | 2b38776 | 2014-07-18 06:07:19 +0200 | [diff] [blame] | 1 | /* |
| 2 | * (C) Copyright 2014 |
| 3 | * Heiko Schocher, DENX Software Engineering, hs@denx.de. |
| 4 | * |
| 5 | * Basic support for the pwm modul 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..3 */ |
| 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 | break; |
| 25 | case 1: |
| 26 | return (struct pwm_regs *)PWM2_BASE_ADDR; |
| 27 | break; |
| 28 | case 2: |
| 29 | return (struct pwm_regs *)PWM3_BASE_ADDR; |
| 30 | break; |
| 31 | case 3: |
| 32 | return (struct pwm_regs *)PWM4_BASE_ADDR; |
| 33 | break; |
| 34 | default: |
| 35 | printf("unknown pwm_id: %d\n", pwm_id); |
| 36 | break; |
| 37 | } |
| 38 | return NULL; |
| 39 | } |
| 40 | |
| 41 | int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c, |
| 42 | unsigned long *duty_c, unsigned long *prescale) |
| 43 | { |
| 44 | unsigned long long c; |
| 45 | |
| 46 | /* |
| 47 | * we have not yet a clock framework for imx6, so add the clock |
| 48 | * value here as a define. Replace it when we have the clock |
| 49 | * framework. |
| 50 | */ |
| 51 | c = CONFIG_IMX6_PWM_PER_CLK; |
| 52 | c = c * period_ns; |
| 53 | do_div(c, 1000000000); |
| 54 | *period_c = c; |
| 55 | |
| 56 | *prescale = *period_c / 0x10000 + 1; |
| 57 | |
| 58 | *period_c /= *prescale; |
| 59 | c = (unsigned long long)(*period_c * duty_ns); |
| 60 | do_div(c, period_ns); |
| 61 | *duty_c = c; |
| 62 | |
| 63 | /* |
| 64 | * according to imx pwm RM, the real period value should be |
| 65 | * PERIOD value in PWMPR plus 2. |
| 66 | */ |
| 67 | if (*period_c > 2) |
| 68 | *period_c -= 2; |
| 69 | else |
| 70 | *period_c = 0; |
| 71 | |
| 72 | return 0; |
| 73 | } |