[PATCH v6 1/3] dt: bindings: add documentation for zx2967 family thermal sensor

[PATCH v6 1/3] dt: bindings: add documentation for zx2967 family thermal sensor

[Baoyou Xie]

This patch adds dt-binding documentation for zx2967 family thermal sensor.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
---
 .../devicetree/bindings/thermal/zx2967-thermal.txt | 114 +++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/thermal/zx2967-thermal.txt

diff --git a/Documentation/devicetree/bindings/thermal/zx2967-thermal.txt b/Documentation/devicetree/bindings/thermal/zx2967-thermal.txt
new file mode 100644
index 0000000..00c4900
--- /dev/null
+++ b/Documentation/devicetree/bindings/thermal/zx2967-thermal.txt
@@ -0,0 +1,114 @@
+* ZTE zx2967 family Thermal
+
+Required Properties:
+- compatible: should be one of the following.
+    * zte,zx296718-thermal
+- reg: physical base address of the controller and length of memory mapped
+    region.
+- clocks : Pairs of phandle and specifier referencing the controller's clocks.
+- clock-names: "gate" for the topcrm clock.
+	       "pclk" for the apb clock.
+- coefficients: Coefficients of thermal sensor, note that those values need to
+		be multiplied by 1000, consists of:
+		slope of calibration cure.
+		offset of calibration cure.
+- #thermal-sensor-cells: must be 0.
+
+Example for tempsensor:
+
+	tempsensor: tempsensor@148a000 {
+		compatible = "zte,zx296718-thermal";
+		reg = <0x0148a000 0x20>;
+		clocks = <&topcrm TEMPSENSOR_GATE>, <&audiocrm AUDIO_TS_PCLK>;
+		clock-names = "gate", "pclk";
+		coefficients = <1951 (-922)>;
+		#thermal-sensor-cells = <0>;
+	};
+
+Example for cooling device:
+
+	cooling_dev: cooling_dev {
+		cluster0_cooling_dev: cluster0-cooling-dev {
+			#cooling-cells = <2>;
+			cpumask = <0xf>;
+			capacitance = <1500>;
+		};
+
+	cluster1_cooling_dev: cluster1-cooling-dev {
+			#cooling-cells = <2>;
+			cpumask = <0x30>;
+			capacitance = <2000>;
+		};
+	};
+
+Example for thermal zones:
+
+	thermal-zones {
+		zx296718_thermal: zx296718_thermal {
+			polling-delay-passive = <500>;
+			polling-delay = <1000>;
+			sustainable-power = <6500>;
+
+			thermal-sensors = <&tempsensor 0>;
+
+			trips {
+				trip0: switch_on_temperature {
+					temperature = <90000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				trip1: desired_temperature {
+					temperature = <100000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				crit: critical_temperature {
+					temperature = <110000>;
+					hysteresis = <2000>;
+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				map0 {
+					trip = <&trip0>;
+					cooling-device = <&gpu 2 5>;
+				};
+
+				map1 {
+					trip = <&trip0>;
+					cooling-device = <&cluster0_cooling_dev 1 2>;
+				};
+
+				map2 {
+					trip = <&trip1>;
+					cooling-device = <&cluster0_cooling_dev 1 2>;
+				};
+
+				map3 {
+					trip = <&crit>;
+					cooling-device = <&cluster0_cooling_dev 1 2>;
+				};
+
+				map4 {
+					trip = <&trip0>;
+					cooling-device = <&cluster1_cooling_dev 1 2>;
+					contribution = <9000>;
+				};
+
+				map5 {
+					trip = <&trip1>;
+					cooling-device = <&cluster1_cooling_dev 1 2>;
+					contribution = <4096>;
+				};
+
+				map6 {
+					trip = <&crit>;
+					cooling-device = <&cluster1_cooling_dev 1 2>;
+					contribution = <4096>;
+				};
+			};
+		};
+	};
-- 
2.7.4

[PATCH v6 2/3] MAINTAINERS: add zx2967 thermal drivers to ARM ZTE architecture

[Baoyou Xie]

Add the zx2967 thermal drivers as maintained by ARM ZTE
architecture maintainers, as they're parts of the core IP.

Signed-off-by: Baoyou Xie <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 MAINTAINERS | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 5fb9b62..edfdea3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1989,10 +1989,12 @@ F:	arch/arm/mach-zx/
 F:	drivers/clk/zte/
 F:	drivers/reset/reset-zx2967.c
 F:	drivers/soc/zte/
+F:	drivers/thermal/zx*
 F:	Documentation/devicetree/bindings/arm/zte.txt
 F:	Documentation/devicetree/bindings/clock/zx296702-clk.txt
 F:	Documentation/devicetree/bindings/reset/zte,zx2967-reset.txt
 F:	Documentation/devicetree/bindings/soc/zte/
+F:	Documentation/devicetree/bindings/thermal/zx*
 F:	include/dt-bindings/soc/zx*.h
 
 ARM/ZYNQ ARCHITECTURE
-- 
2.7.4

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[PATCH v6 3/3] thermal: zx2967: add thermal driver for ZTE's zx2967 family

[Baoyou Xie]

This patch adds thermal driver for ZTE's zx2967 family.

Signed-off-by: Baoyou Xie <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 drivers/thermal/Kconfig          |   8 ++
 drivers/thermal/Makefile         |   1 +
 drivers/thermal/zx2967_thermal.c | 265 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 274 insertions(+)
 create mode 100644 drivers/thermal/zx2967_thermal.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 18f2de6..f64bd50 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -444,4 +444,12 @@ config BCM2835_THERMAL
 	help
 	  Support for thermal sensors on Broadcom bcm2835 SoCs.
 
+config ZX2967_THERMAL
+	tristate "Thermal sensors on zx2967 SoC"
+	depends on ARCH_ZX || COMPILE_TEST
+	help
+	  Enable the zx2967 thermal sensors driver, which supports
+	  the primitive temperature sensor embedded in zx2967 SoCs.
+	  This sensor generates the real time die temperature.
+
 endif
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 677c6d9..c00c05e 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -57,3 +57,4 @@ obj-$(CONFIG_HISI_THERMAL)     += hisi_thermal.o
 obj-$(CONFIG_MTK_THERMAL)	+= mtk_thermal.o
 obj-$(CONFIG_GENERIC_ADC_THERMAL)	+= thermal-generic-adc.o
 obj-$(CONFIG_BCM2835_THERMAL)	+= bcm2835_thermal.o
+obj-$(CONFIG_ZX2967_THERMAL)	+= zx2967_thermal.o
diff --git a/drivers/thermal/zx2967_thermal.c b/drivers/thermal/zx2967_thermal.c
new file mode 100644
index 0000000..d8642cf
--- /dev/null
+++ b/drivers/thermal/zx2967_thermal.c
@@ -0,0 +1,265 @@
+/*
+ * ZTE's zx2967 family thermal sensor driver
+ *
+ * Copyright (C) 2017 ZTE Ltd.
+ *
+ * Author: Baoyou Xie <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/thermal.h>
+
+/* Power Mode: 0->low 1->high */
+#define ZX2967_THERMAL_POWER_MODE	0
+
+/* DCF Control Register */
+#define ZX2967_THERMAL_DCF		0x4
+
+/* Selection Register */
+#define ZX2967_THERMAL_SEL		0x8
+
+/* Control Register */
+#define ZX2967_THERMAL_CTRL		0x10
+
+#define ZX2967_THERMAL_READY		0x1000
+#define ZX2967_THERMAL_TEMP_MASK	0xfff
+#define ZX2967_THERMAL_ID_MASK		0x18
+#define ZX2967_THERMAL_ID0		0x8
+#define ZX2967_THERMAL_ID1		0x10
+
+struct zx2967_thermal_sensor {
+	struct zx2967_thermal_priv *priv;
+	struct thermal_zone_device *tzd;
+	int id;
+};
+
+#define NUM_SENSORS	1
+
+struct zx2967_thermal_priv {
+	struct zx2967_thermal_sensor	sensors[NUM_SENSORS];
+	/* Prevents reads sensor in parallel */
+	struct mutex			lock;
+	struct clk			*clk_gate;
+	struct clk			*pclk;
+	s32				slope;
+	s32				offset;
+	void __iomem			*regs;
+	struct device			*dev;
+};
+
+static int zx2967_thermal_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
+
+	if (priv && priv->pclk)
+		clk_disable_unprepare(priv->pclk);
+
+	if (priv && priv->clk_gate)
+		clk_disable_unprepare(priv->clk_gate);
+
+	return 0;
+}
+
+static int zx2967_thermal_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
+	int error;
+
+	error = clk_prepare_enable(priv->clk_gate);
+	if (error)
+		return error;
+
+	error = clk_prepare_enable(priv->pclk);
+	if (error) {
+		clk_disable_unprepare(priv->clk_gate);
+		return error;
+	}
+
+	return 0;
+}
+
+static int zx2967_thermal_get_temp(void *data, int *temp)
+{
+	void __iomem *regs;
+	struct zx2967_thermal_sensor *sensor = data;
+	struct zx2967_thermal_priv *priv = sensor->priv;
+	unsigned long timeout = jiffies + msecs_to_jiffies(100);
+	u32 val, sel_id;
+
+	regs = priv->regs;
+	mutex_lock(&priv->lock);
+
+	writel_relaxed(0, regs + ZX2967_THERMAL_POWER_MODE);
+	writel_relaxed(2, regs + ZX2967_THERMAL_DCF);
+
+	val = readl_relaxed(regs + ZX2967_THERMAL_SEL);
+	val &= ~ZX2967_THERMAL_ID_MASK;
+	sel_id = sensor->id ? ZX2967_THERMAL_ID0 : ZX2967_THERMAL_ID1;
+	val |= sel_id;
+	writel_relaxed(val, regs + ZX2967_THERMAL_SEL);
+
+	usleep_range(100, 300);
+	val = readl_relaxed(regs + ZX2967_THERMAL_CTRL);
+	while (!(val & ZX2967_THERMAL_READY)) {
+		if (time_after(jiffies, timeout)) {
+			dev_err(priv->dev, "Thermal sensor %d data timeout\n",
+				sensor->id);
+			mutex_unlock(&priv->lock);
+			return -ETIMEDOUT;
+		}
+		usleep_range(100, 300);
+		val = readl_relaxed(regs + ZX2967_THERMAL_CTRL);
+	}
+
+	writel_relaxed(3, regs + ZX2967_THERMAL_DCF);
+	val = readl_relaxed(regs + ZX2967_THERMAL_CTRL)
+			 & ZX2967_THERMAL_TEMP_MASK;
+	writel_relaxed(1, regs + ZX2967_THERMAL_POWER_MODE);
+
+	/* Calculate temperature */
+	*temp = DIV_ROUND_CLOSEST(((s32)val + priv->offset) * 1000,
+				  priv->slope);
+
+	mutex_unlock(&priv->lock);
+
+	return 0;
+}
+
+static struct thermal_zone_of_device_ops zx2967_of_thermal_ops = {
+	.get_temp = zx2967_thermal_get_temp,
+};
+
+static int zx2967_thermal_probe(struct platform_device *pdev)
+{
+	struct zx2967_thermal_priv *priv;
+	struct resource *res;
+	u32 buf[2];
+	int ret, i;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->regs))
+		return PTR_ERR(priv->regs);
+
+	ret = of_property_read_u32_array(pdev->dev.of_node,
+					 "coefficients", buf, 2);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to read coefficients\n");
+		return ret;
+	}
+	priv->slope = (s32)buf[0];
+	priv->offset = (s32)buf[1];
+
+	priv->clk_gate = devm_clk_get(&pdev->dev, "gate");
+	if (IS_ERR(priv->clk_gate)) {
+		ret = PTR_ERR(priv->clk_gate);
+		dev_err(&pdev->dev, "failed to get clock gate: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(priv->clk_gate);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to enable converter clock: %d\n",
+			ret);
+		return ret;
+	}
+
+	priv->pclk = devm_clk_get(&pdev->dev, "pclk");
+	if (IS_ERR(priv->pclk)) {
+		ret = PTR_ERR(priv->pclk);
+		clk_disable_unprepare(priv->clk_gate);
+		dev_err(&pdev->dev, "failed to get apb clock: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(priv->pclk);
+	if (ret) {
+		clk_disable_unprepare(priv->clk_gate);
+		dev_err(&pdev->dev, "failed to enable converter clock: %d\n",
+			ret);
+		return ret;
+	}
+
+	mutex_init(&priv->lock);
+	for (i = 0; i < NUM_SENSORS; i++) {
+		struct zx2967_thermal_sensor *sensor = &priv->sensors[i];
+
+		sensor->priv = priv;
+		sensor->id = i;
+		sensor->tzd = thermal_zone_of_sensor_register(&pdev->dev,
+					i, sensor, &zx2967_of_thermal_ops);
+		if (IS_ERR(sensor->tzd)) {
+			ret = PTR_ERR(sensor->tzd);
+			dev_err(&pdev->dev, "failed to register sensor %d: %d\n",
+				i, ret);
+			goto remove_ts;
+		}
+	}
+	priv->dev = &pdev->dev;
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+
+remove_ts:
+	clk_disable_unprepare(priv->clk_gate);
+	clk_disable_unprepare(priv->pclk);
+	for (i--; i >= 0; i--)
+		thermal_zone_of_sensor_unregister(&pdev->dev,
+						  priv->sensors[i].tzd);
+
+	return ret;
+}
+
+static int zx2967_thermal_exit(struct platform_device *pdev)
+{
+	struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < NUM_SENSORS; i++) {
+		struct zx2967_thermal_sensor *sensor = &priv->sensors[i];
+
+		thermal_zone_of_sensor_unregister(&pdev->dev, sensor->tzd);
+	}
+	clk_disable_unprepare(priv->pclk);
+	clk_disable_unprepare(priv->clk_gate);
+
+	return 0;
+}
+
+static const struct of_device_id zx2967_thermal_id_table[] = {
+	{ .compatible = "zte,zx296718-thermal" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, zx2967_thermal_id_table);
+
+static SIMPLE_DEV_PM_OPS(zx2967_thermal_pm_ops,
+			 zx2967_thermal_suspend, zx2967_thermal_resume);
+
+static struct platform_driver zx2967_thermal_driver = {
+	.probe = zx2967_thermal_probe,
+	.remove = zx2967_thermal_exit,
+	.driver = {
+		.name = "zx2967_thermal",
+		.of_match_table = zx2967_thermal_id_table,
+		.pm = &zx2967_thermal_pm_ops,
+	},
+};
+module_platform_driver(zx2967_thermal_driver);
+
+MODULE_AUTHOR("Baoyou Xie <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>");
+MODULE_DESCRIPTION("ZTE zx2967 thermal driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

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Re: [PATCH v6 3/3] thermal: zx2967: add thermal driver for ZTE's zx2967 family

[Eduardo Valentin]

Helllo Baoyou,

Sorry I was not clear enough in my previous comment.

Please find the explanation below:


On Thu, Feb 02, 2017 at 11:08:06PM +0800, Baoyou Xie wrote:
> This patch adds thermal driver for ZTE's zx2967 family.
> 

<cut>

> +
> +static int zx2967_thermal_probe(struct platform_device *pdev)
> +{
> +	struct zx2967_thermal_priv *priv;
> +	struct resource *res;
> +	u32 buf[2];
> +	int ret, i;
> +
> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	priv->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(priv->regs))
> +		return PTR_ERR(priv->regs);
> +
> +	ret = of_property_read_u32_array(pdev->dev.of_node,
> +					 "coefficients", buf, 2);

What I meant in my previous comment is that of-thermal already does the
above parsing for you. Therefore, the above line is not needed. And...

> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to read coefficients\n");
> +		return ret;
> +	}
> +	priv->slope = (s32)buf[0];
> +	priv->offset = (s32)buf[1];
> +

You should also not need to have priv data for storing the slope and
offset.

> +	priv->clk_gate = devm_clk_get(&pdev->dev, "gate");
> +	if (IS_ERR(priv->clk_gate)) {
> +		ret = PTR_ERR(priv->clk_gate);
> +		dev_err(&pdev->dev, "failed to get clock gate: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(priv->clk_gate);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to enable converter clock: %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	priv->pclk = devm_clk_get(&pdev->dev, "pclk");
> +	if (IS_ERR(priv->pclk)) {
> +		ret = PTR_ERR(priv->pclk);
> +		clk_disable_unprepare(priv->clk_gate);
> +		dev_err(&pdev->dev, "failed to get apb clock: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(priv->pclk);
> +	if (ret) {
> +		clk_disable_unprepare(priv->clk_gate);
> +		dev_err(&pdev->dev, "failed to enable converter clock: %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	mutex_init(&priv->lock);
> +	for (i = 0; i < NUM_SENSORS; i++) {
> +		struct zx2967_thermal_sensor *sensor = &priv->sensors[i];
> +
> +		sensor->priv = priv;
> +		sensor->id = i;
> +		sensor->tzd = thermal_zone_of_sensor_register(&pdev->dev,
> +					i, sensor, &zx2967_of_thermal_ops);

After calling the above function, if it succeeds, and you have the
coefficients property in your DTS, then

> +		if (IS_ERR(sensor->tzd)) {
> +			ret = PTR_ERR(sensor->tzd);
> +			dev_err(&pdev->dev, "failed to register sensor %d: %d\n",
> +				i, ret);
> +			goto remove_ts;
> +		}

Right here, you should be able to access sensor->tzd->tzp->slope and
sensor->tzd->tzp->offset, if you added the entry:
		coefficients = <SLOPE OFFSET>;

		in you thermal zone in DT.

I hope this clarifies.

Let me know if you are able to use the parsing from of-thermal, instead
of in your driver.

> +	}
> +	priv->dev = &pdev->dev;
> +	platform_set_drvdata(pdev, priv);
> +
> +	return 0;
> +
> +remove_ts:
> +	clk_disable_unprepare(priv->clk_gate);
> +	clk_disable_unprepare(priv->pclk);
> +	for (i--; i >= 0; i--)
> +		thermal_zone_of_sensor_unregister(&pdev->dev,
> +						  priv->sensors[i].tzd);
> +
> +	return ret;
> +}
> +
> +static int zx2967_thermal_exit(struct platform_device *pdev)
> +{
> +	struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
> +	int i;
> +
> +	for (i = 0; i < NUM_SENSORS; i++) {
> +		struct zx2967_thermal_sensor *sensor = &priv->sensors[i];
> +
> +		thermal_zone_of_sensor_unregister(&pdev->dev, sensor->tzd);
> +	}
> +	clk_disable_unprepare(priv->pclk);
> +	clk_disable_unprepare(priv->clk_gate);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id zx2967_thermal_id_table[] = {
> +	{ .compatible = "zte,zx296718-thermal" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, zx2967_thermal_id_table);
> +
> +static SIMPLE_DEV_PM_OPS(zx2967_thermal_pm_ops,
> +			 zx2967_thermal_suspend, zx2967_thermal_resume);
> +
> +static struct platform_driver zx2967_thermal_driver = {
> +	.probe = zx2967_thermal_probe,
> +	.remove = zx2967_thermal_exit,
> +	.driver = {
> +		.name = "zx2967_thermal",
> +		.of_match_table = zx2967_thermal_id_table,
> +		.pm = &zx2967_thermal_pm_ops,
> +	},
> +};
> +module_platform_driver(zx2967_thermal_driver);
> +
> +MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 thermal driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.7.4
> 

Re: [PATCH v6 3/3] thermal: zx2967: add thermal driver for ZTE's zx2967 family

[Mathieu Poirier]

On Thu, Feb 02, 2017 at 11:08:06PM +0800, Baoyou Xie wrote:
> This patch adds thermal driver for ZTE's zx2967 family.
> 
> Signed-off-by: Baoyou Xie <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
>  drivers/thermal/Kconfig          |   8 ++
>  drivers/thermal/Makefile         |   1 +
>  drivers/thermal/zx2967_thermal.c | 265 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 274 insertions(+)
>  create mode 100644 drivers/thermal/zx2967_thermal.c
> 
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 18f2de6..f64bd50 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -444,4 +444,12 @@ config BCM2835_THERMAL
>  	help
>  	  Support for thermal sensors on Broadcom bcm2835 SoCs.
>  
> +config ZX2967_THERMAL
> +	tristate "Thermal sensors on zx2967 SoC"
> +	depends on ARCH_ZX || COMPILE_TEST
> +	help
> +	  Enable the zx2967 thermal sensors driver, which supports
> +	  the primitive temperature sensor embedded in zx2967 SoCs.
> +	  This sensor generates the real time die temperature.
> +
>  endif
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 677c6d9..c00c05e 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -57,3 +57,4 @@ obj-$(CONFIG_HISI_THERMAL)     += hisi_thermal.o
>  obj-$(CONFIG_MTK_THERMAL)	+= mtk_thermal.o
>  obj-$(CONFIG_GENERIC_ADC_THERMAL)	+= thermal-generic-adc.o
>  obj-$(CONFIG_BCM2835_THERMAL)	+= bcm2835_thermal.o
> +obj-$(CONFIG_ZX2967_THERMAL)	+= zx2967_thermal.o
> diff --git a/drivers/thermal/zx2967_thermal.c b/drivers/thermal/zx2967_thermal.c
> new file mode 100644
> index 0000000..d8642cf
> --- /dev/null
> +++ b/drivers/thermal/zx2967_thermal.c
> @@ -0,0 +1,265 @@
> +/*
> + * ZTE's zx2967 family thermal sensor driver
> + *
> + * Copyright (C) 2017 ZTE Ltd.
> + *
> + * Author: Baoyou Xie <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> + *
> + * License terms: GNU General Public License (GPL) version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/thermal.h>
> +
> +/* Power Mode: 0->low 1->high */
> +#define ZX2967_THERMAL_POWER_MODE	0
> +
> +/* DCF Control Register */
> +#define ZX2967_THERMAL_DCF		0x4
> +
> +/* Selection Register */
> +#define ZX2967_THERMAL_SEL		0x8
> +
> +/* Control Register */
> +#define ZX2967_THERMAL_CTRL		0x10
> +
> +#define ZX2967_THERMAL_READY		0x1000
> +#define ZX2967_THERMAL_TEMP_MASK	0xfff
> +#define ZX2967_THERMAL_ID_MASK		0x18
> +#define ZX2967_THERMAL_ID0		0x8
> +#define ZX2967_THERMAL_ID1		0x10
> +
> +struct zx2967_thermal_sensor {
> +	struct zx2967_thermal_priv *priv;
> +	struct thermal_zone_device *tzd;
> +	int id;
> +};
> +
> +#define NUM_SENSORS	1
> +
> +struct zx2967_thermal_priv {
> +	struct zx2967_thermal_sensor	sensors[NUM_SENSORS];

Do we really need an array here if there's only 1 sensor?

> +	/* Prevents reads sensor in parallel */
> +	struct mutex			lock;
> +	struct clk			*clk_gate;
> +	struct clk			*pclk;
> +	s32				slope;
> +	s32				offset;
> +	void __iomem			*regs;
> +	struct device			*dev;
> +};

Please add proper kernel style documentation for both structure.  And as far as
I can tell the stuctures could be merged into a single one. 

> +
> +static int zx2967_thermal_suspend(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
> +
> +	if (priv && priv->pclk)
> +		clk_disable_unprepare(priv->pclk);
> +
> +	if (priv && priv->clk_gate)
> +		clk_disable_unprepare(priv->clk_gate);
> +
> +	return 0;
> +}
> +
> +static int zx2967_thermal_resume(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
> +	int error;
> +
> +	error = clk_prepare_enable(priv->clk_gate);
> +	if (error)
> +		return error;
> +
> +	error = clk_prepare_enable(priv->pclk);
> +	if (error) {
> +		clk_disable_unprepare(priv->clk_gate);
> +		return error;
> +	}
> +
> +	return 0;
> +}

The above two function need to be enclosed with CONFIG_PM_SLEEP.  Have a look at
other drivers that are using SIMPLE_DEV_PM_OPS.

> +
> +static int zx2967_thermal_get_temp(void *data, int *temp)
> +{
> +	void __iomem *regs;
> +	struct zx2967_thermal_sensor *sensor = data;
> +	struct zx2967_thermal_priv *priv = sensor->priv;
> +	unsigned long timeout = jiffies + msecs_to_jiffies(100);
> +	u32 val, sel_id;
> +
> +	regs = priv->regs;
> +	mutex_lock(&priv->lock);
> +
> +	writel_relaxed(0, regs + ZX2967_THERMAL_POWER_MODE);
> +	writel_relaxed(2, regs + ZX2967_THERMAL_DCF);
> +
> +	val = readl_relaxed(regs + ZX2967_THERMAL_SEL);
> +	val &= ~ZX2967_THERMAL_ID_MASK;
> +	sel_id = sensor->id ? ZX2967_THERMAL_ID0 : ZX2967_THERMAL_ID1;
> +	val |= sel_id;
> +	writel_relaxed(val, regs + ZX2967_THERMAL_SEL);
> +
> +	usleep_range(100, 300);

Polling (like below) can't be use here?  If not provide a good explanation as to
why that is the case.

> +	val = readl_relaxed(regs + ZX2967_THERMAL_CTRL);
> +	while (!(val & ZX2967_THERMAL_READY)) {
> +		if (time_after(jiffies, timeout)) {
> +			dev_err(priv->dev, "Thermal sensor %d data timeout\n",
> +				sensor->id);
> +			mutex_unlock(&priv->lock);
> +			return -ETIMEDOUT;
> +		}
> +		usleep_range(100, 300);
> +		val = readl_relaxed(regs + ZX2967_THERMAL_CTRL);
> +	}

See if you can use readx_poll_timeout()

> +
> +	writel_relaxed(3, regs + ZX2967_THERMAL_DCF);
> +	val = readl_relaxed(regs + ZX2967_THERMAL_CTRL)
> +			 & ZX2967_THERMAL_TEMP_MASK;
> +	writel_relaxed(1, regs + ZX2967_THERMAL_POWER_MODE);

Please add a #define (along with an explanation) for the values used with
writel_relaxed().  Otherwise reviewers are left guessing. 

> +
> +	/* Calculate temperature */
> +	*temp = DIV_ROUND_CLOSEST(((s32)val + priv->offset) * 1000,
> +				  priv->slope);

Same here, I have to guess why 1000 is used.

> +
> +	mutex_unlock(&priv->lock);
> +
> +	return 0;
> +}
> +
> +static struct thermal_zone_of_device_ops zx2967_of_thermal_ops = {
> +	.get_temp = zx2967_thermal_get_temp,
> +};
> +
> +static int zx2967_thermal_probe(struct platform_device *pdev)
> +{
> +	struct zx2967_thermal_priv *priv;
> +	struct resource *res;
> +	u32 buf[2];
> +	int ret, i;
> +
> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	priv->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(priv->regs))
> +		return PTR_ERR(priv->regs);
> +
> +	ret = of_property_read_u32_array(pdev->dev.of_node,
> +					 "coefficients", buf, 2);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to read coefficients\n");
> +		return ret;
> +	}
> +	priv->slope = (s32)buf[0];
> +	priv->offset = (s32)buf[1];

Are you sure you don't want to check the values of ->slope and ->offset?  I
certainly wouldn't trust the DT...

> +
> +	priv->clk_gate = devm_clk_get(&pdev->dev, "gate");
> +	if (IS_ERR(priv->clk_gate)) {
> +		ret = PTR_ERR(priv->clk_gate);
> +		dev_err(&pdev->dev, "failed to get clock gate: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(priv->clk_gate);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to enable converter clock: %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	priv->pclk = devm_clk_get(&pdev->dev, "pclk");
> +	if (IS_ERR(priv->pclk)) {
> +		ret = PTR_ERR(priv->pclk);
> +		clk_disable_unprepare(priv->clk_gate);

An error path is already defined below - add a 'goto' statement that jumps to
it.  That way it consolidates the exit point for the function and avoid code
duplication.  

> +		dev_err(&pdev->dev, "failed to get apb clock: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(priv->pclk);
> +	if (ret) {
> +		clk_disable_unprepare(priv->clk_gate);

Same comment a above.

> +		dev_err(&pdev->dev, "failed to enable converter clock: %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	mutex_init(&priv->lock);
> +	for (i = 0; i < NUM_SENSORS; i++) {
> +		struct zx2967_thermal_sensor *sensor = &priv->sensors[i];
> +
> +		sensor->priv = priv;
> +		sensor->id = i;
> +		sensor->tzd = thermal_zone_of_sensor_register(&pdev->dev,
> +					i, sensor, &zx2967_of_thermal_ops);
> +		if (IS_ERR(sensor->tzd)) {
> +			ret = PTR_ERR(sensor->tzd);
> +			dev_err(&pdev->dev, "failed to register sensor %d: %d\n",
> +				i, ret);
> +			goto remove_ts;
> +		}
> +	}
> +	priv->dev = &pdev->dev;
> +	platform_set_drvdata(pdev, priv);
> +
> +	return 0;
> +
> +remove_ts:
> +	clk_disable_unprepare(priv->clk_gate);
> +	clk_disable_unprepare(priv->pclk);
> +	for (i--; i >= 0; i--)
> +		thermal_zone_of_sensor_unregister(&pdev->dev,
> +						  priv->sensors[i].tzd);
> +
> +	return ret;
> +}
> +
> +static int zx2967_thermal_exit(struct platform_device *pdev)
> +{
> +	struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
> +	int i;
> +
> +	for (i = 0; i < NUM_SENSORS; i++) {
> +		struct zx2967_thermal_sensor *sensor = &priv->sensors[i];
> +
> +		thermal_zone_of_sensor_unregister(&pdev->dev, sensor->tzd);
> +	}
> +	clk_disable_unprepare(priv->pclk);
> +	clk_disable_unprepare(priv->clk_gate);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id zx2967_thermal_id_table[] = {
> +	{ .compatible = "zte,zx296718-thermal" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, zx2967_thermal_id_table);
> +
> +static SIMPLE_DEV_PM_OPS(zx2967_thermal_pm_ops,
> +			 zx2967_thermal_suspend, zx2967_thermal_resume);
> +
> +static struct platform_driver zx2967_thermal_driver = {
> +	.probe = zx2967_thermal_probe,
> +	.remove = zx2967_thermal_exit,
> +	.driver = {
> +		.name = "zx2967_thermal",
> +		.of_match_table = zx2967_thermal_id_table,
> +		.pm = &zx2967_thermal_pm_ops,
> +	},
> +};
> +module_platform_driver(zx2967_thermal_driver);
> +
> +MODULE_AUTHOR("Baoyou Xie <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 thermal driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.7.4
> 
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