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SubjectRe: [PATCH v4 2/3] thermal: hisilicon: add thermal sensor driver for Hi3660
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Hi Kevin,


On 29/08/2017 10:17, Tao Wang wrote:
> From: Tao Wang <kevin.wangtao@linaro.org>
>
> This patch adds the support for thermal sensor of Hi3660 SoC.

for the Hi3660 SoC thermal sensor.

> this will register sensors for thermal framework and use device
> tree to bind cooling device.

Is it possible to give a pointer to some documentation or to describe
the hardware?

An explanation of the adc min max coef[] range[] conversion would be nice.

In addition, having the rational behind the average and the max would be
nice. Do we really need both avg and max as virtual sensor?

> Signed-off-by: Tao Wang <kevin.wangtao@linaro.org>
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
> drivers/thermal/Kconfig | 13 +++
> drivers/thermal/Makefile | 1 +
> drivers/thermal/hisi_tsensor.c | 209 +++++++++++++++++++++++++++++++++++++++++


IMO, we don't need a new file, but merge this code with the current
hisi_thermal.c driver. BTW, the hi6220 has also a tsensor which is
different from this one.

I suggest to base the hi3660 thermal driver on top of the cleanup I sent
for the hi6220.

> 3 files changed, 223 insertions(+)
> create mode 100644 drivers/thermal/hisi_tsensor.c
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index b5b5fac..32f582d 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -203,6 +203,19 @@ config HISI_THERMAL
> thermal framework. cpufreq is used as the cooling device to throttle
> CPUs when the passive trip is crossed.
>
> +config HISI_TSENSOR
> + tristate "Hisilicon tsensor driver"
> + depends on ARCH_HISI || COMPILE_TEST
> + depends on HAS_IOMEM
> + depends on OF
> + default y
> + help
> + Enable this to plug Hisilicon's tsensor driver into the Linux thermal
> + framework. Besides all the hardware sensors, this also support two
> + virtual sensors, one for maximum of all the hardware sensor, and
> + one for average of all the hardware sensor.
> + Compitable with Hi3660 or higher.

s/Compitable/Compatible/

> +
> config IMX_THERMAL
> tristate "Temperature sensor driver for Freescale i.MX SoCs"
> depends on (ARCH_MXC && CPU_THERMAL) || COMPILE_TEST
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 094d703..8a16bd4 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_ST_THERMAL) += st/
> obj-$(CONFIG_QCOM_TSENS) += qcom/
> obj-$(CONFIG_TEGRA_SOCTHERM) += tegra/
> obj-$(CONFIG_HISI_THERMAL) += hisi_thermal.o
> +obj-$(CONFIG_HISI_TSENSOR) += hisi_tsensor.o
> obj-$(CONFIG_MTK_THERMAL) += mtk_thermal.o
> obj-$(CONFIG_GENERIC_ADC_THERMAL) += thermal-generic-adc.o
> obj-$(CONFIG_ZX2967_THERMAL) += zx2967_thermal.o
> diff --git a/drivers/thermal/hisi_tsensor.c b/drivers/thermal/hisi_tsensor.c
> new file mode 100644
> index 0000000..34cf2ba
> --- /dev/null
> +++ b/drivers/thermal/hisi_tsensor.c
> @@ -0,0 +1,209 @@
> +/*
> + * linux/drivers/thermal/hisi_tsensor.c
> + *
> + * Copyright (c) 2017 Hisilicon Limited.
> + * Copyright (c) 2017 Linaro Limited.
> + *
> + * Author: Tao Wang <kevin.wangtao@linaro.org>
> + * Author: Leo Yan <leo.yan@linaro.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/of.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/thermal.h>
> +
> +#include "thermal_core.h"
> +
> +#define VIRTUAL_SENSORS 2
> +
> +/* hisi Thermal Sensor Dev Structure */
> +struct hisi_thermal_sensor {
> + struct hisi_thermal_data *thermal;
> + struct thermal_zone_device *tzd;
> + void __iomem *sensor_reg;
> + unsigned int id;
> +};
> +
> +struct hisi_thermal_data {
> + struct platform_device *pdev;
> + struct hisi_thermal_sensor *sensors;
> + unsigned int range[2];
> + unsigned int coef[2];
> + unsigned int max_hw_sensor;
> +};
> +
> +static int hisi_thermal_get_temp(void *_sensor, int *temp)
> +{
> + struct hisi_thermal_sensor *sensor = _sensor;
> + struct hisi_thermal_data *data = sensor->thermal;
> + unsigned int idx, adc_min, adc_max, max_sensor;
> + int val, average = 0, max = 0;
> +
> + adc_min = data->range[0];
> + adc_max = data->range[1];
> + max_sensor = data->max_hw_sensor;
> +
> + if (sensor->id < max_sensor) {
> + val = readl(sensor->sensor_reg);
> + val = clamp_val(val, adc_min, adc_max);
That looks a bit fuzzy. Why not create a get_temp for physical sensor
and another one for the virtual? So there will be a clear distinction
between both.

> + } else {
> + for (idx = 0; idx < max_sensor; idx++) {
> + val = readl(data->sensors[idx].sensor_reg);

Below, it is assumed thermal_zone_of_sensor_register() can fail and
sensor->tzd becomes NULL. But no check is done here with the sensor's
tzd. Shall the code assume we take all the sensors even if a thermal
zone failed to register ?

> + val = clamp_val(val, adc_min, adc_max);
> + average += val;
> + if (val > max)
> + max = val;
> + }
> +
> + if (sensor->id == max_sensor)
> + val = max;
> + else
> + val = average / max_sensor;
> + }
>
> + *temp = ((val - adc_min) * data->coef[0]) / (adc_max - adc_min)
> + + data->coef[1];

Pre-compute (adc_max - adc_min) at init time and check it is greater
than zero, otherwise for a bad DT configuration we can end up with
division by zero and crash the kernel (assuming having adc ranges in the
DT is what we want).

> + return 0;
> +}
> +
> +static struct thermal_zone_of_device_ops hisi_of_thermal_ops = {
> + .get_temp = hisi_thermal_get_temp,
> +};
> +
> +static void hisi_thermal_toggle_sensor(struct hisi_thermal_sensor *sensor,
> + bool on)
> +{
> + struct thermal_zone_device *tzd = sensor->tzd;
> +
> + tzd->ops->set_mode(tzd,
> + on ? THERMAL_DEVICE_ENABLED : THERMAL_DEVICE_DISABLED);
> +}
> +
> +static int hisi_thermal_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev->of_node;
> + struct hisi_thermal_data *data;
> + struct hisi_thermal_sensor *sensor;
> + struct resource *res;
> + unsigned int max_sensor;
> + int ret, i;
> +
> + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + data->pdev = pdev;
> + ret = of_property_read_u32(np, "hisi,tsensors", &max_sensor);
> + if (ret < 0) {
> + dev_err(dev, "failed to get max sensor\n");
> + return -EINVAL;
> + }
> + data->max_hw_sensor = max_sensor;

Do we really need a max sensor definition in the DT? Isn't it something
we can deduce by looping with platform_get_resource below ?

eg.

while ((res = platform_get_resource(..., num_sensor++)) {
...
}
That said, I think we can assume there are 3 sensors always, no?

> + data->sensors = devm_kzalloc(dev,
> + sizeof(*data->sensors) * (max_sensor + VIRTUAL_SENSORS),
> + GFP_KERNEL);
> + if (IS_ERR(data->sensors)) {

s/IS_ERR(data->sensors)/!data->sensors/

> + dev_err(dev, "failed to alloc sensors\n");

No message on memory allocation failure, there is already one from the
mm framework.

> + return -ENOMEM;
> + }
> +
> + ret = of_property_read_u32_array(np, "hisi,coef", data->coef, 2);
> + if (ret < 0) {
> + dev_err(dev, "failed to get coef\n");
> + return -EINVAL;

return ret;

> + }
> +
> + ret = of_property_read_u32_array(np, "hisi,adc-range", data->range, 2);
> + if (ret < 0) {
> + dev_err(dev, "failed to get range\n");
> + return -EINVAL;

return ret;

> + }

Are these data really needed through DT? Isn't it something we can hardcode?

> + platform_set_drvdata(pdev, data);
> +
> + for (i = 0; i < max_sensor + VIRTUAL_SENSORS; ++i) {
> + sensor = &data->sensors[i];
> + if (i < max_sensor) {
> + res = platform_get_resource(pdev, IORESOURCE_MEM, i);

Error check?

> + sensor->sensor_reg = devm_ioremap_resource(dev, res);
> + if (IS_ERR(sensor->sensor_reg)) {
> + dev_err(dev, "failed to get reg base\n");
> + return -ENOMEM;

s/-ENOMEM/PTR_ERR(sensor->sensor_reg)/

> + }
> + }
> +
> + sensor->id = i;

How can we deal with holes in the DT?

> + sensor->thermal = data;
> + sensor->tzd = thermal_zone_of_sensor_register(dev,
> + i, sensor, &hisi_of_thermal_ops);
> + if (IS_ERR(sensor->tzd)) {
> + sensor->tzd = NULL;
> + } else {
> + hisi_thermal_toggle_sensor(sensor, true);
> + dev_info(dev, "thermal sensor%d registered\n", i);
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int hisi_thermal_exit(struct platform_device *pdev)
> +{
> + struct hisi_thermal_data *data = platform_get_drvdata(pdev);
> + int i;
> +
> + for (i = 0; i < data->max_hw_sensor + VIRTUAL_SENSORS; i++) {
> + struct hisi_thermal_sensor *sensor = &data->sensors[i];
> +
> + if (!sensor->tzd)
> + continue;
> +
> + hisi_thermal_toggle_sensor(sensor, false);
> + thermal_zone_of_sensor_unregister(&pdev->dev, sensor->tzd);
> + }
> +
> + return 0;
> +}
> +
> +static const struct of_device_id hisi_thermal_id_table[] = {
> + { .compatible = "hisilicon,hi3660-tsensor" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, hisi_thermal_id_table);
> +
> +static struct platform_driver hisi_thermal_driver = {
> + .probe = hisi_thermal_probe,
> + .remove = hisi_thermal_exit,
> + .driver = {
> + .name = "hisi_tsensor",
> + .of_match_table = hisi_thermal_id_table,
> + },
> +};
> +
> +module_platform_driver(hisi_thermal_driver);
> +
> +MODULE_AUTHOR("Tao Wang <kevin.wangtao@linaro.org>");
> +MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
> +MODULE_DESCRIPTION("hisi tsensor driver");
> +MODULE_LICENSE("GPL v2");
>


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