From cadf29dc2a8bcaae83e6e4c3229965de747c8601 Mon Sep 17 00:00:00 2001 From: Caesar Wang Date: Mon, 12 Dec 2016 19:05:34 +0800 Subject: [PATCH] thermal: rockchip: optimize the conversion table In order to support the valid temperature can conver to analog value. The rockchip thermal driver has not supported the all valid temperature to convert the analog value. (e.g.: 61C, 62C, 63C....) For example: In some cases, we need adjust the trip point. $cd /sys/class/thermal/thermal_zone* $echo 68000 > trip_point_0_temp That will return the max analogic value indicates the invalid before posting this patch. So, this patch will optimize the conversion table to support the other cases. Signed-off-by: Caesar Wang Signed-off-by: Eduardo Valentin --- drivers/thermal/rockchip_thermal.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c index f027b86b993d..cacc12b44ca1 100644 --- a/drivers/thermal/rockchip_thermal.c +++ b/drivers/thermal/rockchip_thermal.c @@ -317,6 +317,7 @@ static const struct tsadc_table rk3288_code_table[] = { {3452, 115000}, {3437, 120000}, {3421, 125000}, + {0, 125000}, }; static const struct tsadc_table rk3368_code_table[] = { @@ -401,10 +402,12 @@ static u32 rk_tsadcv2_temp_to_code(const struct chip_tsadc_table *table, int temp) { int high, low, mid; + unsigned long num; + unsigned int denom; u32 error = table->data_mask; low = 0; - high = table->length - 1; + high = (table->length - 1) - 1; /* ignore the last check for table */ mid = (high + low) / 2; /* Return mask code data when the temp is over table range */ @@ -421,6 +424,26 @@ static u32 rk_tsadcv2_temp_to_code(const struct chip_tsadc_table *table, mid = (low + high) / 2; } + /* + * The conversion code granularity provided by the table. Let's + * assume that the relationship between temperature and + * analog value between 2 table entries is linear and interpolate + * to produce less granular result. + */ + num = abs(table->id[mid + 1].code - table->id[mid].code); + num *= temp - table->id[mid].temp; + denom = table->id[mid + 1].temp - table->id[mid].temp; + + switch (table->mode) { + case ADC_DECREMENT: + return table->id[mid].code - (num / denom); + case ADC_INCREMENT: + return table->id[mid].code + (num / denom); + default: + pr_err("%s: unknown table mode: %d\n", __func__, table->mode); + return error; + } + exit: pr_err("%s: invalid temperature, temp=%d error=%d\n", __func__, temp, error); -- 2.20.1