git.openwrt.org Git - openwrt/staging/linusw.git/blob

   1 From c2ab54ab0425388e65901a7af2fbf69ead968708 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?N=C3=ADcolas=20F=2E=20R=2E=20A=2E=20Prado?=
   3  <nfraprado@collabora.com>
   4 Date: Thu, 13 Jul 2023 11:42:37 -0400
   5 Subject: [PATCH 33/42] thermal/drivers/mediatek/lvts_thermal: Make readings
   6  valid in filtered mode
   7 MIME-Version: 1.0
   8 Content-Type: text/plain; charset=UTF-8
   9 Content-Transfer-Encoding: 8bit
  10
  11 Currently, when a controller is configured to use filtered mode, thermal
  12 readings are valid only about 30% of the time.
  13
  14 Upon testing, it was noticed that lowering any of the interval settings
  15 resulted in an improved rate of valid data. The same was observed when
  16 decreasing the number of samples for each sensor (which also results in
  17 quicker measurements).
  18
  19 Retrying the read with a timeout longer than the time it takes to
  20 resample (about 344us with these settings and 4 sensors) also improves
  21 the rate.
  22
  23 Lower all timing settings to the minimum, configure the filtering to
  24 single sample, and poll the measurement register for at least one period
  25 to improve the data validity on filtered mode.  With these changes in
  26 place, out of 100000 reads, a single one failed, ie 99.999% of the data
  27 was valid.
  28
  29 Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
  30 Tested-by: Chen-Yu Tsai <wenst@chromium.org>
  31 Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
  32 Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
  33 Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
  34 Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
  35 Link: https://lore.kernel.org/r/20230713154743.611870-1-nfraprado@collabora.com
  36 ---
  37  drivers/thermal/mediatek/lvts_thermal.c | 19 ++++++++++++-------
  38  1 file changed, 12 insertions(+), 7 deletions(-)
  39
  40 --- a/drivers/thermal/mediatek/lvts_thermal.c
  41 +++ b/drivers/thermal/mediatek/lvts_thermal.c
  42 @@ -58,11 +58,11 @@
  43  #define LVTS_PROTTC(__base)            (__base + 0x00CC)
  44  #define LVTS_CLKEN(__base)             (__base + 0x00E4)
  45
  46 -#define LVTS_PERIOD_UNIT                       ((118 * 1000) / (256 * 38))
  47 -#define LVTS_GROUP_INTERVAL                    1
  48 -#define LVTS_FILTER_INTERVAL           1
  49 -#define LVTS_SENSOR_INTERVAL           1
  50 -#define LVTS_HW_FILTER                         0x2
  51 +#define LVTS_PERIOD_UNIT                       0
  52 +#define LVTS_GROUP_INTERVAL                    0
  53 +#define LVTS_FILTER_INTERVAL           0
  54 +#define LVTS_SENSOR_INTERVAL           0
  55 +#define LVTS_HW_FILTER                         0x0
  56  #define LVTS_TSSEL_CONF                                0x13121110
  57  #define LVTS_CALSCALE_CONF                     0x300
  58  #define LVTS_MONINT_CONF                       0x8300318C
  59 @@ -86,6 +86,9 @@
  60  #define LVTS_MSR_IMMEDIATE_MODE                0
  61  #define LVTS_MSR_FILTERED_MODE         1
  62
  63 +#define LVTS_MSR_READ_TIMEOUT_US       400
  64 +#define LVTS_MSR_READ_WAIT_US          (LVTS_MSR_READ_TIMEOUT_US / 2)
  65 +
  66  #define LVTS_HW_SHUTDOWN_MT8195                105000
  67
  68  #define LVTS_MINIMUM_THRESHOLD         20000
  69 @@ -268,6 +271,7 @@ static int lvts_get_temp(struct thermal_
  70         struct lvts_sensor *lvts_sensor = thermal_zone_device_priv(tz);
  71         void __iomem *msr = lvts_sensor->msr;
  72         u32 value;
  73 +       int rc;
  74
  75         /*
  76          * Measurement registers:
  77 @@ -280,7 +284,8 @@ static int lvts_get_temp(struct thermal_
  78          * 16   : Valid temperature
  79          * 15-0 : Raw temperature
  80          */
  81 -       value = readl(msr);
  82 +       rc = readl_poll_timeout(msr, value, value & BIT(16),
  83 +                               LVTS_MSR_READ_WAIT_US, LVTS_MSR_READ_TIMEOUT_US);
  84
  85         /*
  86          * As the thermal zone temperature will read before the
  87 @@ -293,7 +298,7 @@ static int lvts_get_temp(struct thermal_
  88          * functionning temperature and directly jump to a system
  89          * shutdown.
  90          */
  91 -       if (!(value & BIT(16)))
  92 +       if (rc)
  93                 return -EAGAIN;
  94
  95         *temp = lvts_raw_to_temp(value & 0xFFFF);