From 0b58c08b593d082858e74503bdf553ea01f9f15a Mon Sep 17 00:00:00 2001 From: Marc Gonzalez Date: Tue, 19 Apr 2016 16:21:16 +0200 Subject: thermal: add temperature sensor support for tango SoC The Tango thermal driver provides support for the primitive temperature sensor embedded in Tango chips since the SMP8758. This sensor only generates a 1-bit signal to indicate whether the die temperature exceeds a programmable threshold. Signed-off-by: Marc Gonzalez Signed-off-by: Eduardo Valentin --- drivers/thermal/Kconfig | 9 ++++ drivers/thermal/Makefile | 1 + drivers/thermal/tango_thermal.c | 111 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 121 insertions(+) create mode 100644 drivers/thermal/tango_thermal.c (limited to 'drivers/thermal') diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index a6777cb..ee02e60 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -389,6 +389,15 @@ depends on ARCH_STI && OF source "drivers/thermal/st/Kconfig" endmenu +config TANGO_THERMAL + tristate "Tango thermal management" + depends on ARCH_TANGO || COMPILE_TEST + help + Enable the Tango thermal driver, which supports the primitive + temperature sensor embedded in Tango chips since the SMP8758. + This sensor only generates a 1-bit signal to indicate whether + the die temperature exceeds a programmable threshold. + source "drivers/thermal/tegra/Kconfig" config QCOM_SPMI_TEMP_ALARM diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index d64f7f7..998134f 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -35,6 +35,7 @@ obj-y += samsung/ obj-$(CONFIG_DOVE_THERMAL) += dove_thermal.o obj-$(CONFIG_DB8500_THERMAL) += db8500_thermal.o obj-$(CONFIG_ARMADA_THERMAL) += armada_thermal.o +obj-$(CONFIG_TANGO_THERMAL) += tango_thermal.o obj-$(CONFIG_IMX_THERMAL) += imx_thermal.o obj-$(CONFIG_DB8500_CPUFREQ_COOLING) += db8500_cpufreq_cooling.o obj-$(CONFIG_INTEL_POWERCLAMP) += intel_powerclamp.o diff --git a/drivers/thermal/tango_thermal.c b/drivers/thermal/tango_thermal.c new file mode 100644 index 0000000..d6592bf --- /dev/null +++ b/drivers/thermal/tango_thermal.c @@ -0,0 +1,111 @@ +#include +#include +#include +#include +#include + +/* + * According to a data sheet draft, "this temperature sensor uses a bandgap + * type of circuit to compare a voltage which has a negative temperature + * coefficient with a voltage that is proportional to absolute temperature. + * A resistor bank allows 41 different temperature thresholds to be selected + * and the logic output will then indicate whether the actual die temperature + * lies above or below the selected threshold." + */ + +#define TEMPSI_CMD 0 +#define TEMPSI_RES 4 +#define TEMPSI_CFG 8 + +#define CMD_OFF 0 +#define CMD_ON 1 +#define CMD_READ 2 + +#define IDX_MIN 15 +#define IDX_MAX 40 + +struct tango_thermal_priv { + void __iomem *base; + int thresh_idx; +}; + +static bool temp_above_thresh(void __iomem *base, int thresh_idx) +{ + writel(CMD_READ | thresh_idx << 8, base + TEMPSI_CMD); + usleep_range(10, 20); + writel(CMD_READ | thresh_idx << 8, base + TEMPSI_CMD); + + return readl(base + TEMPSI_RES); +} + +static int tango_get_temp(void *arg, int *res) +{ + struct tango_thermal_priv *priv = arg; + int idx = priv->thresh_idx; + + if (temp_above_thresh(priv->base, idx)) { + /* Search upward by incrementing thresh_idx */ + while (idx < IDX_MAX && temp_above_thresh(priv->base, ++idx)) + cpu_relax(); + idx = idx - 1; /* always return lower bound */ + } else { + /* Search downward by decrementing thresh_idx */ + while (idx > IDX_MIN && !temp_above_thresh(priv->base, --idx)) + cpu_relax(); + } + + *res = (idx * 9 / 2 - 38) * 1000; /* millidegrees Celsius */ + priv->thresh_idx = idx; + + return 0; +} + +static const struct thermal_zone_of_device_ops ops = { + .get_temp = tango_get_temp, +}; + +static int tango_thermal_probe(struct platform_device *pdev) +{ + struct resource *res; + struct tango_thermal_priv *priv; + struct thermal_zone_device *tzdev; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + priv->thresh_idx = IDX_MIN; + writel(CMD_ON, priv->base + TEMPSI_CMD); + + tzdev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, priv, &ops); + if (IS_ERR(tzdev)) + return PTR_ERR(tzdev); + + return 0; +} + +static const struct of_device_id tango_sensor_ids[] = { + { + .compatible = "sigma,smp8758-thermal", + }, + { /* sentinel */ } +}; + +static struct platform_driver tango_thermal_driver = { + .probe = tango_thermal_probe, + .driver = { + .name = "tango-thermal", + .of_match_table = tango_sensor_ids, + }, +}; + +module_platform_driver(tango_thermal_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sigma Designs"); +MODULE_DESCRIPTION("Tango temperature sensor"); -- cgit v1.1