Re: [PATCH v15 5/8] hwmon: sy7636a: Add temperature driver for sy7636a

From: Guenter Roeck
Date: Wed Nov 10 2021 - 10:55:39 EST

On Wed, Nov 10, 2021 at 10:29:45PM +1000, Alistair Francis wrote:
> This is a multi-function device to interface with the sy7636a
> EPD PMIC chip from Silergy.
>
> Signed-off-by: Alistair Francis <alistair@xxxxxxxxxxxxx>
> ---
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/sy7636a-hwmon.rst | 24 ++++++
> drivers/hwmon/Kconfig | 9 +++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/sy7636a-hwmon.c | 108 ++++++++++++++++++++++++++
> 5 files changed, 143 insertions(+)
> create mode 100644 Documentation/hwmon/sy7636a-hwmon.rst
> create mode 100644 drivers/hwmon/sy7636a-hwmon.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 7046bf1870d9..a887308850cd 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -180,6 +180,7 @@ Hardware Monitoring Kernel Drivers
> smsc47m1
> sparx5-temp
> stpddc60
> + sy7636a-hwmon
> tc654
> tc74
> thmc50
> diff --git a/Documentation/hwmon/sy7636a-hwmon.rst b/Documentation/hwmon/sy7636a-hwmon.rst
> new file mode 100644
> index 000000000000..6b3e36d028dd
> --- /dev/null
> +++ b/Documentation/hwmon/sy7636a-hwmon.rst
> @@ -0,0 +1,24 @@
> +Kernel driver sy7636a-hwmon
> +=========================
> +
> +Supported chips:
> +
> + * Silergy SY7636A PMIC
> +
> +
> +Description
> +-----------
> +
> +This driver adds hardware temperature reading support for
> +the Silergy SY7636A PMIC.
> +
> +The following sensors are supported
> +
> + * Temperature
> + - SoC on-die temperature in milli-degree C
> +
> +sysfs-Interface
> +---------------
> +
> +temp0_input
> + - SoC on-die temperature (milli-degree C)
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 64bd3dfba2c4..3139a286c35a 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1662,6 +1662,15 @@ config SENSORS_SIS5595
> This driver can also be built as a module. If so, the module
> will be called sis5595.
>
> +config SENSORS_SY7636A
> + tristate "Silergy SY7636A"
> + help
> + If you say yes here you get support for the thermistor readout of
> + the Silergy SY7636A PMIC.
> +
> + This driver can also be built as a module. If so, the module
> + will be called sy7636a-hwmon.
> +
> config SENSORS_DME1737
> tristate "SMSC DME1737, SCH311x and compatibles"
> depends on I2C && !PPC
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index baee6a8d4dd1..8f8da52098d1 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -182,6 +182,7 @@ obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o
> obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
> obj-$(CONFIG_SENSORS_SPARX5) += sparx5-temp.o
> obj-$(CONFIG_SENSORS_STTS751) += stts751.o
> +obj-$(CONFIG_SENSORS_SY7636A) += sy7636a-hwmon.o
> obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o
> obj-$(CONFIG_SENSORS_TC74) += tc74.o
> obj-$(CONFIG_SENSORS_THMC50) += thmc50.o
> diff --git a/drivers/hwmon/sy7636a-hwmon.c b/drivers/hwmon/sy7636a-hwmon.c
> new file mode 100644
> index 000000000000..84ceaae3a404
> --- /dev/null
> +++ b/drivers/hwmon/sy7636a-hwmon.c
> @@ -0,0 +1,108 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Functions to access SY3686A power management chip temperature
> + *
> + * Copyright (C) 2021 reMarkable AS - http://www.remarkable.com/
> + *
> + * Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@xxxxxxxxxxxxxx>
> + * Alistair Francis <alistair@xxxxxxxxxxxxx>
> + */
> +
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/machine.h>
> +
> +#include <linux/mfd/sy7636a.h>
> +
> +static int sy7636a_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *temp)
> +{
> + struct regmap *regmap = dev_get_drvdata(dev);
> + int ret, reg_val;
> +
> + ret = regmap_read(regmap,
> + SY7636A_REG_TERMISTOR_READOUT, &reg_val);
> + if (ret)
> + return ret;
> +
> + *temp = reg_val * 1000;
> +
> + return 0;
> +}
> +
> +static umode_t sy7636a_is_visible(const void *data,
> + enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + if (type != hwmon_temp)
> + return 0;
> +
> + if (attr != hwmon_temp_input)
> + return 0;
> +
> + return 0444;
> +}
> +
> +static const struct hwmon_ops sy7636a_hwmon_ops = {
> + .is_visible = sy7636a_is_visible,
> + .read = sy7636a_read,
> +};
> +
> +static const struct hwmon_channel_info *sy7636a_info[] = {
> + HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
> + HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
> + NULL
> +};
> +
> +static const struct hwmon_chip_info sy7636a_chip_info = {
> + .ops = &sy7636a_hwmon_ops,
> + .info = sy7636a_info,
> +};
> +
> +static int sy7636a_sensor_probe(struct platform_device *pdev)
> +{
> + struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
> + struct regulator *regulator;
> + struct device *hwmon_dev;
> + int err;
> +
> + if (!regmap)
> + return -EPROBE_DEFER;
> +
> + regulator = devm_regulator_get(&pdev->dev, "vcom");
> + if (IS_ERR(regulator)) {
> + return PTR_ERR(regulator);
> + }
> +
> + err = regulator_enable(regulator);
> + if (err) {
> + regulator_put(regulator);

Is this needed ? I would have assumed that the devm_ function
above would ensure that the put is handled automatically.

Guenter

> + return err;
> + }
> +
> + hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
> + "sy7636a_temperature", regmap, &sy7636a_chip_info, NULL);
> +
> + if (IS_ERR(hwmon_dev)) {
> + err = PTR_ERR(hwmon_dev);
> + dev_err(&pdev->dev, "Unable to register hwmon device, returned %d\n", err);
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +static struct platform_driver sy7636a_sensor_driver = {
> + .probe = sy7636a_sensor_probe,
> + .driver = {
> + .name = "sy7636a-temperature",
> + },
> +};
> +module_platform_driver(sy7636a_sensor_driver);
> +
> +MODULE_DESCRIPTION("SY7636A sensor driver");
> +MODULE_LICENSE("GPL");
> --
> 2.31.1
>