From 36564d7e53f9efd14ab5692cd9475a75e8000c98 Mon Sep 17 00:00:00 2001 From: Andrey Smirnov Date: Tue, 10 Dec 2019 08:41:51 -0800 Subject: [PATCH] thermal: qoriq: Do not report invalid temperature reading Before returning measured temperature data to upper layer we need to make sure that the reading was marked as "valid" to avoid reporting bogus data. Signed-off-by: Andrey Smirnov Reviewed-by: Daniel Lezcano Tested-by: Lucas Stach Cc: Chris Healy Cc: Lucas Stach Cc: Eduardo Valentin Cc: Daniel Lezcano Cc: Angus Ainslie (Purism) Cc: linux-imx@nxp.com Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20191210164153.10463-11-andrew.smirnov@gmail.com --- drivers/thermal/qoriq_thermal.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/thermal/qoriq_thermal.c b/drivers/thermal/qoriq_thermal.c index 9a45594..1730dbe 100644 --- a/drivers/thermal/qoriq_thermal.c +++ b/drivers/thermal/qoriq_thermal.c @@ -49,6 +49,7 @@ #define REGS_TRITSR(n) (0x100 + 16 * (n)) /* Immediate Temperature * Site Register */ +#define TRITSR_V BIT(31) #define REGS_TTRnCR(n) (0xf10 + 4 * (n)) /* Temperature Range n * Control Register */ @@ -81,8 +82,24 @@ static int tmu_get_temp(void *p, int *temp) struct qoriq_sensor *qsensor = p; struct qoriq_tmu_data *qdata = qoriq_sensor_to_data(qsensor); u32 val; + /* + * REGS_TRITSR(id) has the following layout: + * + * 31 ... 7 6 5 4 3 2 1 0 + * V TEMP + * + * Where V bit signifies if the measurement is ready and is + * within sensor range. TEMP is an 8 bit value representing + * temperature in C. + */ + if (regmap_read_poll_timeout(qdata->regmap, + REGS_TRITSR(qsensor->id), + val, + val & TRITSR_V, + USEC_PER_MSEC, + 10 * USEC_PER_MSEC)) + return -ENODATA; - regmap_read(qdata->regmap, REGS_TRITSR(qsensor->id), &val); *temp = (val & 0xff) * 1000; return 0; -- 2.7.4