Commit 0b58c08b authored by Marc Gonzalez's avatar Marc Gonzalez Committed by Eduardo Valentin

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: default avatarMarc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: default avatarEduardo Valentin <edubezval@gmail.com>
parent 469ace07
* Tango Thermal
The SMP8758 SoC includes 3 instances of this temperature sensor
(in the CPU, video decoder, and PCIe controller).
Required properties:
- #thermal-sensor-cells: Should be 0 (see thermal.txt)
- compatible: "sigma,smp8758-thermal"
- reg: Address range of the thermal registers
Example:
cpu_temp: thermal@920100 {
#thermal-sensor-cells = <0>;
compatible = "sigma,smp8758-thermal";
reg = <0x920100 12>;
};
......@@ -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
......
......@@ -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
......
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/thermal.h>
#include <linux/platform_device.h>
/*
* 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");
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