From dbdaa582e4ee38c9e2c2d500ebb102a350b7e1fc Mon Sep 17 00:00:00 2001 From: Amit Kucheria Date: Wed, 20 Mar 2019 18:47:56 +0530 Subject: [PATCH] drivers: thermal: tsens: simplify get_temp_tsens_v2 routine The current implementation is based on an algorithm published in the docs. Instead of reading the temperature thrice w/o any explanation, improve the algorithm. This will become the basis for a common get_temp routine in the future. Signed-off-by: Amit Kucheria Signed-off-by: Eduardo Valentin --- drivers/thermal/qcom/tsens-v2.c | 55 ++++++++++----------------------- 1 file changed, 17 insertions(+), 38 deletions(-) diff --git a/drivers/thermal/qcom/tsens-v2.c b/drivers/thermal/qcom/tsens-v2.c index 01ec1b2681f2..780e16b09b28 100644 --- a/drivers/thermal/qcom/tsens-v2.c +++ b/drivers/thermal/qcom/tsens-v2.c @@ -25,58 +25,37 @@ #define TM_Sn_STATUS_OFF 0x00a0 #define TM_TRDY_OFF 0x00e4 -#define LAST_TEMP_MASK 0xfff - -static int get_temp_tsens_v2(struct tsens_priv *priv, int id, int *temp) +static int get_temp_tsens_v2(struct tsens_priv *priv, int i, int *temp) { - struct tsens_sensor *s = &priv->sensor[id]; + struct tsens_sensor *s = &priv->sensor[i]; u32 temp_idx = LAST_TEMP_0 + s->hw_id; u32 valid_idx = VALID_0 + s->hw_id; - u32 last_temp = 0, last_temp2 = 0, last_temp3 = 0, valid; + u32 last_temp = 0, valid, mask; int ret; - ret = regmap_field_read(priv->rf[temp_idx], &last_temp); - if (ret) - return ret; - ret = regmap_field_read(priv->rf[valid_idx], &valid); if (ret) return ret; - - if (valid) - goto done; - - /* Try a second time */ - ret = regmap_field_read(priv->rf[valid_idx], &valid); - if (ret) - return ret; - ret = regmap_field_read(priv->rf[temp_idx], &last_temp2); - if (ret) - return ret; - if (valid) { - last_temp = last_temp2; - goto done; + while (!valid) { + /* Valid bit is 0 for 6 AHB clock cycles. + * At 19.2MHz, 1 AHB clock is ~60ns. + * We should enter this loop very, very rarely. + */ + ndelay(400); + ret = regmap_field_read(priv->rf[valid_idx], &valid); + if (ret) + return ret; } - /* Try a third/last time */ - ret = regmap_field_read(priv->rf[valid_idx], &valid); - if (ret) - return ret; - ret = regmap_field_read(priv->rf[temp_idx], &last_temp3); + /* Valid bit is set, OK to read the temperature */ + ret = regmap_field_read(priv->rf[temp_idx], &last_temp); if (ret) return ret; - if (valid) { - last_temp = last_temp3; - goto done; - } - if (last_temp == last_temp2) - last_temp = last_temp2; - else if (last_temp2 == last_temp3) - last_temp = last_temp3; -done: + mask = GENMASK(priv->fields[LAST_TEMP_0].msb, + priv->fields[LAST_TEMP_0].lsb); /* Convert temperature from deciCelsius to milliCelsius */ - *temp = sign_extend32(last_temp, fls(LAST_TEMP_MASK) - 1) * 100; + *temp = sign_extend32(last_temp, fls(mask) - 1) * 100; return 0; } -- 2.30.2