Re: [PATCH v6 08/13] hwmon: add support for the sl28cpld hardware monitoring controller

Andy Shevchenko
2020-07-26T09:19:04Z

On Sun, Jul 26, 2020 at 01:18:29AM +0200, Michael Walle wrote:
> Add support for the hardware monitoring controller of the sl28cpld board
> management controller. This driver is part of a multi-function device.

FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Signed-off-by: Michael Walle <michael@walle.cc>
> Acked-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Changes since v5:
> - none
>
> Changes since v4:
> - update copyright year
> - remove #include <linux/of_device.h>, suggested by Andy.
> - use PTR_ERR_OR_ZERO(), suggested by Andy.
> - remove the platform device table
> - don't use KBUID_MODNAME
>
> Changes since v3:
> - see cover letter
>
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/sl28cpld.rst | 36 ++++++++
> drivers/hwmon/Kconfig | 10 +++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/sl28cpld-hwmon.c | 142 +++++++++++++++++++++++++++++++
> 5 files changed, 190 insertions(+)
> create mode 100644 Documentation/hwmon/sl28cpld.rst
> create mode 100644 drivers/hwmon/sl28cpld-hwmon.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 750d3a975d82..d90c43c82936 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -154,6 +154,7 @@ Hardware Monitoring Kernel Drivers
> sht3x
> shtc1
> sis5595
> + sl28cpld
> smm665
> smsc47b397
> smsc47m192
> diff --git a/Documentation/hwmon/sl28cpld.rst b/Documentation/hwmon/sl28cpld.rst
> new file mode 100644
> index 000000000000..7ed65f78250c
> --- /dev/null
> +++ b/Documentation/hwmon/sl28cpld.rst
> @@ -0,0 +1,36 @@
> +.. SPDX-License-Identifier: GPL-2.0-only
> +
> +Kernel driver sl28cpld
> +======================
> +
> +Supported chips:
> +
> + * Kontron sl28cpld
> +
> + Prefix: 'sl28cpld'
> +
> + Datasheet: not available
> +
> +Authors: Michael Walle <michael@walle.cc>
> +
> +Description
> +-----------
> +
> +The sl28cpld is a board management controller which also exposes a hardware
> +monitoring controller. At the moment this controller supports a single fan
> +supervisor. In the future there might be other flavours and additional
> +hardware monitoring might be supported.
> +
> +The fan supervisor has a 7 bit counter register and a counter period of 1
> +second. If the 7 bit counter overflows, the supervisor will automatically
> +switch to x8 mode to support a wider input range at the loss of
> +granularity.
> +
> +Sysfs entries
> +-------------
> +
> +The following attributes are supported.
> +
> +======================= ========================================================
> +fan1_input Fan RPM. Assuming 2 pulses per revolution.
> +======================= ========================================================
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 8dc28b26916e..a02829ec7386 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1479,6 +1479,16 @@ config SENSORS_RASPBERRYPI_HWMON
> This driver can also be built as a module. If so, the module
> will be called raspberrypi-hwmon.
>
> +config SENSORS_SL28CPLD
> + tristate "Kontron sl28cpld hardware monitoring driver"
> + select MFD_SIMPLE_MFD_I2C
> + help
> + If you say yes here you get support for the fan supervisor of the
> + sl28cpld board management controller.
> +
> + This driver can also be built as a module. If so, the module
> + will be called sl28cpld-hwmon.
> +
> config SENSORS_SHT15
> tristate "Sensiron humidity and temperature sensors. SHT15 and compat."
> depends on GPIOLIB || COMPILE_TEST
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index a8f4b35b136b..dee8511f9348 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -159,6 +159,7 @@ obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o
> obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
> obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o
> obj-$(CONFIG_SENSORS_SCH5636) += sch5636.o
> +obj-$(CONFIG_SENSORS_SL28CPLD) += sl28cpld-hwmon.o
> obj-$(CONFIG_SENSORS_SHT15) += sht15.o
> obj-$(CONFIG_SENSORS_SHT21) += sht21.o
> obj-$(CONFIG_SENSORS_SHT3x) += sht3x.o
> diff --git a/drivers/hwmon/sl28cpld-hwmon.c b/drivers/hwmon/sl28cpld-hwmon.c
> new file mode 100644
> index 000000000000..e48f58ec5b9c
> --- /dev/null
> +++ b/drivers/hwmon/sl28cpld-hwmon.c
> @@ -0,0 +1,142 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * sl28cpld hardware monitoring driver
> + *
> + * Copyright 2020 Kontron Europe GmbH
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/hwmon.h>
> +#include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +
> +#define FAN_INPUT 0x00
> +#define FAN_SCALE_X8 BIT(7)
> +#define FAN_VALUE_MASK GENMASK(6, 0)
> +
> +struct sl28cpld_hwmon {
> + struct regmap *regmap;
> + u32 offset;
> +};
> +
> +static umode_t sl28cpld_hwmon_is_visible(const void *data,
> + enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + return 0444;
> +}
> +
> +static int sl28cpld_hwmon_read(struct device *dev,
> + enum hwmon_sensor_types type, u32 attr,
> + int channel, long *input)
> +{
> + struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev);
> + unsigned int value;
> + int ret;
> +
> + switch (attr) {
> + case hwmon_fan_input:
> + ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT,
> + &value);
> + if (ret)
> + return ret;
> + /*
> + * The register has a 7 bit value and 1 bit which indicates the
> + * scale. If the MSB is set, then the lower 7 bit has to be
> + * multiplied by 8, to get the correct reading.
> + */
> + if (value & FAN_SCALE_X8)
> + value = FIELD_GET(FAN_VALUE_MASK, value) << 3;
> +
> + /*
> + * The counter period is 1000ms and the sysfs specification
> + * says we should asssume 2 pulses per revolution.
> + */
> + value *= 60 / 2;
> +
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + *input = value;
> + return 0;
> +}
> +
> +static const u32 sl28cpld_hwmon_fan_config[] = {
> + HWMON_F_INPUT,
> + 0
> +};
> +
> +static const struct hwmon_channel_info sl28cpld_hwmon_fan = {
> + .type = hwmon_fan,
> + .config = sl28cpld_hwmon_fan_config,
> +};
> +
> +static const struct hwmon_channel_info *sl28cpld_hwmon_info[] = {
> + &sl28cpld_hwmon_fan,
> + NULL
> +};
> +
> +static const struct hwmon_ops sl28cpld_hwmon_ops = {
> + .is_visible = sl28cpld_hwmon_is_visible,
> + .read = sl28cpld_hwmon_read,
> +};
> +
> +static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = {
> + .ops = &sl28cpld_hwmon_ops,
> + .info = sl28cpld_hwmon_info,
> +};
> +
> +static int sl28cpld_hwmon_probe(struct platform_device *pdev)
> +{
> + struct sl28cpld_hwmon *hwmon;
> + struct device *hwmon_dev;
> + int ret;
> +
> + if (!pdev->dev.parent)
> + return -ENODEV;
> +
> + hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
> + if (!hwmon)
> + return -ENOMEM;
> +
> + hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> + if (!hwmon->regmap)
> + return -ENODEV;
> +
> + ret = device_property_read_u32(&pdev->dev, "reg", &hwmon->offset);
> + if (ret)
> + return -EINVAL;
> +
> + hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
> + "sl28cpld_hwmon", hwmon,
> + &sl28cpld_hwmon_chip_info, NULL);
> + if (IS_ERR(hwmon_dev))
> + dev_err(&pdev->dev, "failed to register as hwmon device");
> +
> + return PTR_ERR_OR_ZERO(hwmon_dev);
> +}
> +
> +static const struct of_device_id sl28cpld_hwmon_of_match[] = {
> + { .compatible = "kontron,sl28cpld-fan" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, sl28cpld_hwmon_of_match);
> +
> +static struct platform_driver sl28cpld_hwmon_driver = {
> + .probe = sl28cpld_hwmon_probe,
> + .driver = {
> + .name = "sl28cpld-fan",
> + .of_match_table = sl28cpld_hwmon_of_match,
> + },
> +};
> +module_platform_driver(sl28cpld_hwmon_driver);
> +
> +MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver");
> +MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
> +MODULE_LICENSE("GPL");
> --
> 2.20.1
>

--
With Best Regards,
Andy Shevchenko