drivers/pwm/pwm-imx-util.c

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