drivers/pwm/pwm-imx-util.c

   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 }