Re: [PATCH 4/8] hwmon: Add support for Azoteq IQS620AT temperature sensor

[Guenter Roeck <linux@roeck-us.net>]

On Sun, Oct 20, 2019 at 11:11:19PM -0500, Jeff LaBundy wrote:
> This patch adds support for the Azoteq IQS620AT temperature sensor,
> capable of reporting its absolute die temperature.
> 
> Signed-off-by: Jeff LaBundy <jeff@labundy.com>

Seems to me this might be more feasible as iio driver.
Jonathan, what do you think ?

> ---
>  drivers/hwmon/Kconfig         | 12 +++++-
>  drivers/hwmon/Makefile        |  1 +
>  drivers/hwmon/iqs620at-temp.c | 96 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 108 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/hwmon/iqs620at-temp.c
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 13a6b4a..3e56be6 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -385,6 +385,16 @@ config SENSORS_ATXP1
>  	  This driver can also be built as a module. If so, the module
>  	  will be called atxp1.
>  
> +config SENSORS_IQS620AT
> +	tristate "Azoteq IQS620AT temperature sensor"
> +	depends on MFD_IQS62X
> +	help
> +	  Say Y here if you want to build support for the Azoteq IQS620AT
> +	  temperature sensor.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called iqs620at-temp.
> +
>  config SENSORS_DS620
>  	tristate "Dallas Semiconductor DS620"
>  	depends on I2C
> @@ -1593,7 +1603,7 @@ config SENSORS_ADS7871
>  
>  config SENSORS_AMC6821
>  	tristate "Texas Instruments AMC6821"
> -	depends on I2C 
> +	depends on I2C

No unrelated changes, please, and most definitely no
unrelated whitespace changes.

>  	help
>  	  If you say yes here you get support for the Texas Instruments
>  	  AMC6821 hardware monitoring chips.
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 40c036e..2360add 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -83,6 +83,7 @@ obj-$(CONFIG_SENSORS_IIO_HWMON) += iio_hwmon.o
>  obj-$(CONFIG_SENSORS_INA209)	+= ina209.o
>  obj-$(CONFIG_SENSORS_INA2XX)	+= ina2xx.o
>  obj-$(CONFIG_SENSORS_INA3221)	+= ina3221.o
> +obj-$(CONFIG_SENSORS_IQS620AT)	+= iqs620at-temp.o
>  obj-$(CONFIG_SENSORS_IT87)	+= it87.o
>  obj-$(CONFIG_SENSORS_JC42)	+= jc42.o
>  obj-$(CONFIG_SENSORS_K8TEMP)	+= k8temp.o
> diff --git a/drivers/hwmon/iqs620at-temp.c b/drivers/hwmon/iqs620at-temp.c
> new file mode 100644
> index 0000000..0af49b6
> --- /dev/null
> +++ b/drivers/hwmon/iqs620at-temp.c
> @@ -0,0 +1,96 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Azoteq IQS620AT Temperature Sensor
> + *
> + * Copyright (C) 2019
> + * Author: Jeff LaBundy <jeff@labundy.com>
> + */
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/iqs62x.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define IQS620_TEMP_UI_OUT			0x1A
> +
> +static umode_t iqs620_temp_is_visible(const void *drvdata,
> +				      enum hwmon_sensor_types type,
> +				      u32 attr, int channel)
> +{
> +	if (type != hwmon_temp || attr != hwmon_temp_input)
> +		return 0;
> +
> +	return 0444;
> +}
> +
> +static int iqs620_temp_read(struct device *dev, enum hwmon_sensor_types type,
> +			    u32 attr, int channel, long *val)
> +{
> +	struct iqs62x_core *iqs62x = dev_get_drvdata(dev);
> +	int error;
> +	__le16 val_buf;
> +
> +	if (type != hwmon_temp || attr != hwmon_temp_input)
> +		return -EINVAL;

			-EOPNOTSUPP
> +
> +	error = regmap_raw_read(iqs62x->map, IQS620_TEMP_UI_OUT, &val_buf,
> +				sizeof(val_buf));
> +	if (error)
> +		return error;
> +
> +	*val = (le16_to_cpu(val_buf) - 100) * 1000;
> +
> +	return 0;
> +}
> +
> +static const struct hwmon_ops iqs620_temp_ops = {
> +	.is_visible = iqs620_temp_is_visible,
> +	.read = iqs620_temp_read,
> +};
> +
> +static const struct hwmon_channel_info *iqs620_temp_channel_info[] = {
> +	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
> +	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
> +	NULL
> +};
> +
> +static const struct hwmon_chip_info iqs620_temp_chip_info = {
> +	.ops = &iqs620_temp_ops,
> +	.info = iqs620_temp_channel_info,
> +};
> +
> +static int iqs620_temp_probe(struct platform_device *pdev)
> +{
> +	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
> +	struct device *hdev;
> +	int error = 0;
> +
> +	hdev = devm_hwmon_device_register_with_info(&pdev->dev,
> +						    iqs62x->dev_desc->dev_name,
> +						    iqs62x,
> +						    &iqs620_temp_chip_info,
> +						    NULL);
> +	if (IS_ERR(hdev)) {
> +		error = PTR_ERR(hdev);
> +		dev_err(&pdev->dev, "Failed to register device: %d\n", error);

Such an error would either be static, caused by bad attributes,
or a bad name, which is already logged, or a memory allocation
failure, which is also already logged. The error message does
therefore not add any value.

> +	}
> +
> +	return error;
> +}
> +
> +static struct platform_driver iqs620_temp_platform_driver = {
> +	.driver = {
> +		.name	= IQS620_DRV_NAME_TEMP,
> +	},
> +	.probe		= iqs620_temp_probe,
> +};
> +module_platform_driver(iqs620_temp_platform_driver);
> +
> +MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
> +MODULE_DESCRIPTION("Azoteq IQS620AT Temperature Sensor");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:" IQS620_DRV_NAME_TEMP);
> -- 
> 2.7.4
>