[PATCH v3 06/23] thermal: armada: average over samples to avoid glitches
From: miquel.raynal@bootlin.com (Miquel Raynal)
Date: 2018-07-05 16:04:20
Also in:
linux-devicetree, linux-pm
Subsystem:
marvell mvebu thermal driver, the rest, thermal · Maintainers:
Miquel Raynal, Linus Torvalds, Rafael J. Wysocki, Daniel Lezcano
Configure the sample frequency and number of averaged samples. This is needed for two reasons: 1/ To be bootloader independent. 2/ To prepare the introduction of multi-sensors support by preventing inconsistencies when reading temperatures that could be a mean of samples took from different sensors. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> --- drivers/thermal/armada_thermal.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)
diff --git a/drivers/thermal/armada_thermal.c b/drivers/thermal/armada_thermal.c
index 9291ea3ad2f7..1f9706d96a0d 100644
--- a/drivers/thermal/armada_thermal.c
+++ b/drivers/thermal/armada_thermal.c@@ -54,7 +54,12 @@ #define CONTROL0_TSEN_START BIT(0) #define CONTROL0_TSEN_RESET BIT(1) #define CONTROL0_TSEN_ENABLE BIT(2) +#define CONTROL0_TSEN_AVG_BYPASS BIT(6) +#define CONTROL0_TSEN_OSR_SHIFT 24 +#define CONTROL0_TSEN_OSR_MAX 0x3 +#define CONTROL1_TSEN_AVG_SHIFT 0 +#define CONTROL1_TSEN_AVG_MASK 0x7 #define CONTROL1_EXT_TSEN_SW_RESET BIT(7) #define CONTROL1_EXT_TSEN_HW_RESETn BIT(8)
@@ -194,6 +199,13 @@ static void armada_ap806_init(struct platform_device *pdev, reg = readl_relaxed(priv->control0); reg &= ~CONTROL0_TSEN_RESET; reg |= CONTROL0_TSEN_START | CONTROL0_TSEN_ENABLE; + + /* Sample every ~2ms */ + reg |= CONTROL0_TSEN_OSR_MAX << CONTROL0_TSEN_OSR_SHIFT; + + /* Enable average (2 samples by default) */ + reg &= ~CONTROL0_TSEN_AVG_BYPASS; + writel(reg, priv->control0); /* Wait the sensors to be valid or the core will warn the user */
@@ -203,7 +215,20 @@ static void armada_ap806_init(struct platform_device *pdev, static void armada_cp110_init(struct platform_device *pdev, struct armada_thermal_priv *priv) { + u32 reg; + armada380_init(pdev, priv); + + /* Sample every ~2ms */ + reg = readl_relaxed(priv->control0); + reg |= CONTROL0_TSEN_OSR_MAX << CONTROL0_TSEN_OSR_SHIFT; + writel(reg, priv->control0); + + /* Average the output value over 2^1 = 2 samples */ + reg = readl_relaxed(priv->control1); + reg &= ~CONTROL1_TSEN_AVG_MASK << CONTROL1_TSEN_AVG_SHIFT; + reg |= 1 << CONTROL1_TSEN_AVG_SHIFT; + writel(reg, priv->control1); } static bool armada_is_valid(struct armada_thermal_priv *priv)
--
2.14.1