target/linux/brcm2708/patches-3.10/0194-lirc_rpi-Use-read_current_timer-to-determine-transmi.patch

   1 From fd945928d6fd544d2f4bdde718b097b01bafb048 Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Tue, 22 Apr 2014 13:58:14 +0100
   4 Subject: [PATCH 194/196] lirc_rpi: Use read_current_timer to determine
   5  transmitter delay. Thanks to jjmz and others See:
   6  https://github.com/raspberrypi/linux/issues/525
   7
   8 ---
   9  drivers/staging/media/lirc/lirc_rpi.c | 32 +++++++++++++++++---------------
  10  1 file changed, 17 insertions(+), 15 deletions(-)
  11
  12 diff --git a/drivers/staging/media/lirc/lirc_rpi.c b/drivers/staging/media/lirc/lirc_rpi.c
  13 index 8aee83f..57ffacf 100644
  14 --- a/drivers/staging/media/lirc/lirc_rpi.c
  15 +++ b/drivers/staging/media/lirc/lirc_rpi.c
  16 @@ -30,6 +30,7 @@
  17  #include <linux/sched.h>
  18  #include <linux/kernel.h>
  19  #include <linux/time.h>
  20 +#include <linux/timex.h>
  21  #include <linux/string.h>
  22  #include <linux/delay.h>
  23  #include <linux/platform_device.h>
  24 @@ -41,7 +42,7 @@
  25
  26  #define LIRC_DRIVER_NAME "lirc_rpi"
  27  #define RBUF_LEN 256
  28 -#define LIRC_TRANSMITTER_LATENCY 256
  29 +#define LIRC_TRANSMITTER_LATENCY 50
  30
  31  #ifndef MAX_UDELAY_MS
  32  #define MAX_UDELAY_US 5000
  33 @@ -107,19 +108,15 @@ static void safe_udelay(unsigned long usecs)
  34  static int init_timing_params(unsigned int new_duty_cycle,
  35         unsigned int new_freq)
  36  {
  37 -       /*
  38 -        * period, pulse/space width are kept with 8 binary places -
  39 -        * IE multiplied by 256.
  40 -        */
  41 -       if (256 * 1000000L / new_freq * new_duty_cycle / 100 <=
  42 +       if (1000 * 1000000L / new_freq * new_duty_cycle / 100 <=
  43             LIRC_TRANSMITTER_LATENCY)
  44                 return -EINVAL;
  45 -       if (256 * 1000000L / new_freq * (100 - new_duty_cycle) / 100 <=
  46 +       if (1000 * 1000000L / new_freq * (100 - new_duty_cycle) / 100 <=
  47             LIRC_TRANSMITTER_LATENCY)
  48                 return -EINVAL;
  49         duty_cycle = new_duty_cycle;
  50         freq = new_freq;
  51 -       period = 256 * 1000000L / freq;
  52 +       period = 1000 * 1000000L / freq;
  53         pulse_width = period * duty_cycle / 100;
  54         space_width = period - pulse_width;
  55         dprintk("in init_timing_params, freq=%d pulse=%ld, "
  56 @@ -130,11 +127,14 @@ static int init_timing_params(unsigned int new_duty_cycle,
  57  static long send_pulse_softcarrier(unsigned long length)
  58  {
  59         int flag;
  60 -       unsigned long actual, target, d;
  61 +       unsigned long actual, target;
  62 +       unsigned long actual_us, initial_us, target_us;
  63
  64 -       length <<= 8;
  65 +       length *= 1000;
  66
  67         actual = 0; target = 0; flag = 0;
  68 +       read_current_timer(&actual_us);
  69 +
  70         while (actual < length) {
  71                 if (flag) {
  72                         gpiochip->set(gpiochip, gpio_out_pin, invert);
  73 @@ -143,17 +143,19 @@ static long send_pulse_softcarrier(unsigned long length)
  74                         gpiochip->set(gpiochip, gpio_out_pin, !invert);
  75                         target += pulse_width;
  76                 }
  77 -               d = (target - actual -
  78 -                    LIRC_TRANSMITTER_LATENCY + 128) >> 8;
  79 +               initial_us = actual_us;
  80 +               target_us = actual_us + (target - actual) / 1000;
  81                 /*
  82                  * Note - we've checked in ioctl that the pulse/space
  83                  * widths are big enough so that d is > 0
  84                  */
  85 -               udelay(d);
  86 -               actual += (d << 8) + LIRC_TRANSMITTER_LATENCY;
  87 +               if  ((int)(target_us - actual_us) > 0)
  88 +                       udelay(target_us - actual_us);
  89 +               read_current_timer(&actual_us);
  90 +               actual += (actual_us - initial_us) * 1000;
  91                 flag = !flag;
  92         }
  93 -       return (actual-length) >> 8;
  94 +       return (actual-length) / 1000;
  95  }
  96
  97  static long send_pulse(unsigned long length)
  98 --
  99 1.9.1
 100