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         case 2:
  27                 return (struct pwm_regs *)PWM3_BASE_ADDR;
  28         case 3:
  29                 return (struct pwm_regs *)PWM4_BASE_ADDR;
  30 #ifdef CONFIG_MX6SX
  31         case 4:
  32                 return (struct pwm_regs *)PWM5_BASE_ADDR;
  33         case 5:
  34                 return (struct pwm_regs *)PWM6_BASE_ADDR;
  35         case 6:
  36                 return (struct pwm_regs *)PWM7_BASE_ADDR;
  37         case 7:
  38                 return (struct pwm_regs *)PWM8_BASE_ADDR;
  39 #endif
  40         default:
  41                 printf("unknown pwm_id: %d\n", pwm_id);
  42                 break;
  43         }
  44         return NULL;
  45 }
  46
  47 int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c,
  48                       unsigned long *duty_c, unsigned long *prescale)
  49 {
  50         unsigned long long c;
  51
  52         /*
  53          * we have not yet a clock framework for imx6, so add the clock
  54          * value here as a define. Replace it when we have the clock
  55          * framework.
  56          */
  57         c = CONFIG_IMX6_PWM_PER_CLK;
  58         c = c * period_ns;
  59         do_div(c, 1000000000);
  60         *period_c = c;
  61
  62         *prescale = *period_c / 0x10000 + 1;
  63
  64         *period_c /= *prescale;
  65         c = *period_c * (unsigned long long)duty_ns;
  66         do_div(c, period_ns);
  67         *duty_c = c;
  68
  69         /*
  70          * according to imx pwm RM, the real period value should be
  71          * PERIOD value in PWMPR plus 2.
  72          */
  73         if (*period_c > 2)
  74                 *period_c -= 2;
  75         else
  76                 *period_c = 0;
  77
  78         return 0;
  79 }