Re: [PATCH v13 5/9] thermal: sy7636a: Add thermal driver for sy7636a

Daniel Lezcano
2021-10-16T10:33:06Z

On 15/10/2021 14:25, Alistair Francis wrote:
> Add thermal driver to enable kernel based polling
> and shutdown of device for temperatures out of spec

As it is an initial submission, could you give a brief description of
the sensor even if it is very simple ?

> Signed-off-by: Alistair Francis <alistair@alistair23.me>
> ---
> drivers/thermal/Kconfig | 6 ++
> drivers/thermal/Makefile | 1 +
> drivers/thermal/sy7636a_thermal.c | 94 +++++++++++++++++++++++++++++++
> 3 files changed, 101 insertions(+)
> create mode 100644 drivers/thermal/sy7636a_thermal.c
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index d7f44deab5b1..6ee0e7de1b37 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -450,6 +450,12 @@ depends on (ARCH_STI || ARCH_STM32) && OF
> source "drivers/thermal/st/Kconfig"
> endmenu
>
> +config SY7636A_THERMAL
> + tristate "SY7636A thermal management"

no deps ?

> + help
> + Enable the sy7636a thermal driver, which supports the
> + temperature sensor embedded in Silabs SY7636A IC.
> +
> source "drivers/thermal/tegra/Kconfig"
>
> config GENERIC_ADC_THERMAL
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 82fc3e616e54..2e1aca8a0a09 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -51,6 +51,7 @@ obj-$(CONFIG_DA9062_THERMAL) += da9062-thermal.o
> obj-y += intel/
> obj-$(CONFIG_TI_SOC_THERMAL) += ti-soc-thermal/
> obj-y += st/
> +obj-$(CONFIG_SY7636A_THERMAL) += sy7636a_thermal.o
> obj-$(CONFIG_QCOM_TSENS) += qcom/
> obj-y += tegra/
> obj-$(CONFIG_HISI_THERMAL) += hisi_thermal.o
> diff --git a/drivers/thermal/sy7636a_thermal.c b/drivers/thermal/sy7636a_thermal.c
> new file mode 100644
> index 000000000000..9e58305ca3ce
> --- /dev/null
> +++ b/drivers/thermal/sy7636a_thermal.c
> @@ -0,0 +1,94 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Functions to access SY3686A power management chip temperature
> + *
> + * Copyright (C) 2019 reMarkable AS - http://www.remarkable.com/

2021

> + *
> + * Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>
> + * Alistair Francis <alistair@alistair23.me>
> + */

From Documentation/process/submitting-drivers.rst

"""
Copyright:
The copyright owner must agree to use of GPL.
It's best if the submitter and copyright owner
are the same person/entity. If not, the name of
the person/entity authorizing use of GPL should be
listed in case it's necessary to verify the will of
the copyright owner.
"""

[Cc'ed Lars Ivar Miljeteig]

> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/thermal.h>
> +
> +#include <linux/mfd/sy7636a.h>
> +
> +static int sy7636a_get_temp(void *arg, int *res)

...(struct thermal_zone_device *tz, int *temp)

> +{
> + unsigned int mode_ctr;
> + int ret, reg_val;
> + struct regmap *regmap = arg;
> + bool isVoltageActive;

Looks like c++ code

> + ret = regmap_read(regmap,
> + SY7636A_REG_OPERATION_MODE_CRL, &mode_ctr);
> + if (ret)
> + return ret;
> +
> + isVoltageActive = mode_ctr & SY7636A_OPERATION_MODE_CRL_ONOFF;
> +
> + /* If operation mode isn't set to control, then let's set it. */
> + if (!isVoltageActive) {
> + ret = regmap_write(regmap,
> + SY7636A_REG_OPERATION_MODE_CRL,
> + mode_ctr | SY7636A_OPERATION_MODE_CRL_ONOFF);
> + if (ret)
> + return ret;
> + }

Who is turnning off the 'control' outside of this driver?

> + ret = regmap_read(regmap,
> + SY7636A_REG_TERMISTOR_READOUT, &reg_val);
> + if (ret)
> + return ret;
> +
> + /* Restore the operation mode if it wasn't set */
> + if (!isVoltageActive) {
> + ret = regmap_write(regmap,
> + SY7636A_REG_OPERATION_MODE_CRL,
> + mode_ctr);
> + if (ret)
> + return ret;
> + }

IIUC, this is a mfd, so if a component outside of this driver is
touching this SY7636A_REG_OPERATION_MODE_CRL, there is no guarantee
these operations will stay consistent.

Is that correct ?

> + *res = reg_val * 1000;
> +
> + return ret;
> +}
> +
> +static const struct thermal_zone_of_device_ops ops = {
> + .get_temp = sy7636a_get_temp,
> +};
> +
> +static int sy7636a_thermal_probe(struct platform_device *pdev)
> +{
> + struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
> + struct thermal_zone_device *thermal_zone_dev;

regmap return value check, please

> + thermal_zone_dev = devm_thermal_zone_of_sensor_register(
> + pdev->dev.parent,
> + 0,
> + regmap,
> + &ops);

Fix indent please

> +
> + return PTR_ERR_OR_ZERO(thermal_zone_dev);
> +}
> +
> +static const struct platform_device_id sy7636a_thermal_id_table[] = {
> + { "sy7636a-thermal", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(platform, sy7636a_thermal_id_table);
> +
> +static struct platform_driver sy7636a_thermal_driver = {
> + .driver = {
> + .name = "sy7636a-thermal",
> + },
> + .probe = sy7636a_thermal_probe,
> + .id_table = sy7636a_thermal_id_table,
> +};
> +module_platform_driver(sy7636a_thermal_driver);
> +
> +MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
> +MODULE_DESCRIPTION("SY7636A thermal driver");
> +MODULE_LICENSE("GPL v2");
>

--
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |