On Wed, Nov 02, 2022 at 12:04:40PM -0300, Joaquín Ignacio Aramendía wrote:
> Sensors driver for OXP Handhelds from One-Netbook that expose fan reading
> and control via hwmon sysfs.
>
> As far as I could gather all OXP boards have the same DMI strings and
> they are told appart by the boot cpu vendor (Intel/AMD).
> Currently only AMD boards are supported.
>
> Fan control is provided via pwm interface in the range [0-255]. AMD
> boards have [0-100] as range in the EC, the written value is scaled to
> accommodate for that.
>
> Signed-off-by: Joaquín Ignacio Aramendía <samsagax@xxxxxxxxx>
> ---
> Added Documentation entry
> Added MAINTAINERS entry
> Removed unnecessary code complexity
> Fixed all checkpatch --strict checks
> ---
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/oxp-sensors.rst | 24 +++
> MAINTAINERS | 6 +
> drivers/hwmon/Kconfig | 11 ++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/oxp-sensors.c | 254 ++++++++++++++++++++++++++++
> 6 files changed, 297 insertions(+)
> create mode 100644 Documentation/hwmon/oxp-sensors.rst
> create mode 100644 drivers/hwmon/oxp-sensors.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index c1d11cf13eef..098986bfbfdd 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -160,6 +160,7 @@ Hardware Monitoring Kernel Drivers
> nzxt-kraken2
> nzxt-smart2
> occ
> + oxp-sensors
> pc87360
> pc87427
> pcf8591
> diff --git a/Documentation/hwmon/oxp-sensors.rst b/Documentation/hwmon/oxp-sensors.rst
> new file mode 100644
> index 000000000000..023441d17a45
> --- /dev/null
> +++ b/Documentation/hwmon/oxp-sensors.rst
> @@ -0,0 +1,24 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver oxp-sensors
> +=========================
> +
> +Authors:
s/Authors/Author/
> + - Joaquín Ignacio Aramendía <samsagax@xxxxxxxxx>
> +
> +Description:
> +------------
> +
> +One X Player devices from One Netbook provide fan readings and fan control
> +through its Embedded Controller.
> +
> +Currently only supports AMD boards from the One X Player lineup. Intel boards
> +could be supported if we could figure out the EC registers and values to write
> +to since the EC layout and model is different.
> +
> +Sensor values are read and written from EC registers, and to avoid race with
> +the board firmware the driver acquires ACPI mutex.
> +
> +Fan control is provided via pwm sysfs attribute in the range [0-255]. AMD
> +boards use [0-100] as range values in the EC, the value is scaled to
> +accommodate for that.
Drop the last two paragraphs; those are implementation details
which belong into the driver.
List the supported sysfs attributes instead (without the scaling detail).
See other driver documentation for examples.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 2034e7d26684..c2e24a830875 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -15337,6 +15337,12 @@ S: Maintained
> F: drivers/mtd/nand/onenand/
> F: include/linux/mtd/onenand*.h
>
> +ONEXPLAYER FAN DRIVER
> +M: Joaquín Ignacio Aramendía <samsagax@xxxxxxxxx>
> +L: linux-hwmon@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: drivers/hwmon/oxp-sensors.c
> +
> ONION OMEGA2+ BOARD
> M: Harvey Hunt <harveyhuntnexus@xxxxxxxxx>
> L: linux-mips@xxxxxxxxxxxxxxx
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 7ac3daaf59ce..993ffa26e44f 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1607,6 +1607,17 @@ config SENSORS_NZXT_SMART2
>
> source "drivers/hwmon/occ/Kconfig"
>
> +config SENSORS_OXP
> + tristate "OneXPlayer EC fan control"
> + depends on ACPI
> + depends on X86
> + help
> + If you say yes here you get support for fan readings and control over
> + OneXPlayer handheld devices. Only OneXPlayer mini AMD handheld variant
> + boards are supported.
> +
> + Can also be built as a module. In that case it will be called oxp-sensors.
> +
> config SENSORS_PCF8591
> tristate "Philips PCF8591 ADC/DAC"
> depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 11d076cad8a2..35824f8be455 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -167,6 +167,7 @@ obj-$(CONFIG_SENSORS_NSA320) += nsa320-hwmon.o
> obj-$(CONFIG_SENSORS_NTC_THERMISTOR) += ntc_thermistor.o
> obj-$(CONFIG_SENSORS_NZXT_KRAKEN2) += nzxt-kraken2.o
> obj-$(CONFIG_SENSORS_NZXT_SMART2) += nzxt-smart2.o
> +obj-$(CONFIG_SENSORS_OXP) += oxp-sensors.o
> obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
> obj-$(CONFIG_SENSORS_PC87427) += pc87427.o
> obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o
> diff --git a/drivers/hwmon/oxp-sensors.c b/drivers/hwmon/oxp-sensors.c
> new file mode 100644
> index 000000000000..00b3aacfb017
> --- /dev/null
> +++ b/drivers/hwmon/oxp-sensors.c
> @@ -0,0 +1,254 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Platform driver for OXP Handhelds that expose fan reading and control
> + * via hwmon sysfs.
> + *
> + * All boards have the same DMI strings and they are told appart by the
> + * boot cpu vendor (Intel/AMD). Currently only AMD boards are supported
> + * but the code is made to be simple to add other handheld boards in the
> + * future.
> + * Fan control is provided via pwm interface in the range [0-255]. AMD
> + * boards use [0-100] as range in the EC, the written value is scaled to
> + * accommodate for that.
> + *
> + * Copyright (C) 2022 Joaquín I. Aramendía <samsagax@xxxxxxxxx>
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/dev_printk.h>
> +#include <linux/dmi.h>
> +#include <linux/hwmon.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/processor.h>
> +
> +/* Handle ACPI lock mechanism */
> +static u32 oxp_mutex;
> +
> +#define ACPI_LOCK_DELAY_MS 500
> +
> +static bool lock_global_acpi_lock(void)
> +{
> + return ACPI_SUCCESS(acpi_acquire_global_lock(ACPI_LOCK_DELAY_MS, &oxp_mutex));
> +}
> +
> +static bool unlock_global_acpi_lock(void)
> +{
> + return ACPI_SUCCESS(acpi_release_global_lock(oxp_mutex));
> +}
> +
> +#define OXP_SENSOR_FAN_REG 0x76 /* Fan reading is 2 registers long */
> +#define OXP_SENSOR_PWM_ENABLE_REG 0x4A /* PWM enable is 1 register long */
> +#define OXP_SENSOR_PWM_REG 0x4B /* PWM reading is 1 register long */
> +
> +static const struct dmi_system_id dmi_table[] = {
> + {
> + .matches = {
> + DMI_MATCH(DMI_BOARD_VENDOR, "ONE-NETBOOK"),
> + DMI_EXACT_MATCH(DMI_BOARD_NAME, "ONE XPLAYER"),
> + },
> + },
> + {},
> +};
> +
> +/* Helper functions to handle EC read/write */
> +static int read_from_ec(u8 reg, int size, long *val)
> +{
> + int i;
> + int ret;
> + u8 buffer;
> +
> + if (!lock_global_acpi_lock())
> + return -EBUSY;
> +
> + *val = 0;
> + for (i = 0; i < size; i++) {
> + ret = ec_read(reg + i, &buffer);
> + if (ret)
> + return ret;
> + *val <<= i * 8;
> + *val += buffer;
> + }
> +
> + if (!unlock_global_acpi_lock())
> + return -EBUSY;
> +
> + return 0;
> +}
> +
> +static int write_to_ec(const struct device *dev, u8 reg, u8 value)
> +{
> + int ret;
> +
> + if (!lock_global_acpi_lock())
> + return -EBUSY;
> +
> + ret = ec_write(reg, value);
> +
> + if (!unlock_global_acpi_lock())
> + return -EBUSY;
> +
> + return ret;
> +}
> +
> +static int oxp_pwm_enable(const struct device *dev)
> +{
> + return write_to_ec(dev, OXP_SENSOR_PWM_ENABLE_REG, 0x01);
> +}
> +
> +static int oxp_pwm_disable(const struct device *dev)
> +{
> + return write_to_ec(dev, OXP_SENSOR_PWM_ENABLE_REG, 0x00);
> +}
> +
> +/* Callbacks for hwmon interface */
> +static umode_t oxp_ec_hwmon_is_visible(const void *drvdata,
> + enum hwmon_sensor_types type, u32 attr, int channel)
> +{
> + switch (type) {
> + case hwmon_fan:
> + return 0444;
> + case hwmon_pwm:
> + return 0644;
> + default:
> + return 0;
> + }
> + return 0;
I think you can drop the above since all branches of the switch statement
return.
> +}
> +
> +static int oxp_platform_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + int ret;
> +
> + switch (type) {
> + case hwmon_fan:
> + switch (attr) {
> + case hwmon_fan_input:
> + return read_from_ec(OXP_SENSOR_FAN_REG, 2, val);
> + default:
Missing break;
> + }
> + break;
> + case hwmon_pwm:
> + switch (attr) {
> + case hwmon_pwm_input:
> + ret = read_from_ec(OXP_SENSOR_PWM_REG, 2, val);
> + *val = (*val * 255) / 100;
That isn't really clean since it will overwrite *val after an error.
if (ret)
return ret;
*val = (*val * 255) / 100;
return 0;
would be more appropriate.
> + return ret;
> + case hwmon_pwm_enable:
> + return read_from_ec(OXP_SENSOR_PWM_ENABLE_REG, 1, val);
> + default:
Missing break;
> + }
> + break;
> + default:
Missing break;
> + }
> + dev_dbg(dev, "Unknown attribute for type %d: %d\n", type, attr);
That isn't really useful since it will never happen.
> + return -EOPNOTSUPP;
> +}
> +
> +static int oxp_platform_write(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long val)
> +{
> + switch (type) {
> + case hwmon_pwm:
> + switch (attr) {
> + case hwmon_pwm_enable:
> + if (val == 1)
> + return oxp_pwm_enable(dev);
> + else if (val == 0)
> + return oxp_pwm_disable(dev);
> + else
> + return -EINVAL;
else after return is unnecessary.
> + case hwmon_pwm_input:
> + if (val < 0 || val > 255)
> + return -EINVAL;
> + val = (val * 100) / 255;
> + return write_to_ec(dev, OXP_SENSOR_PWM_REG, val);
> + default:
> + break;
> + }
break;
> + default:
break;
> + }
> + dev_dbg(dev, "Unknown sensor type: %d", type);
Same as above. It just increases code size for no good reason.
> + return -EOPNOTSUPP;
> +}
> +
> +/* Known sensors in the OXP EC controllers */
> +static const struct hwmon_channel_info *oxp_platform_sensors[] = {
> + HWMON_CHANNEL_INFO(fan,
> + HWMON_F_INPUT),
> + HWMON_CHANNEL_INFO(pwm,
> + HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
> + NULL,
> +};
> +
> +static const struct hwmon_ops oxp_ec_hwmon_ops = {
> + .is_visible = oxp_ec_hwmon_is_visible,
> + .read = oxp_platform_read,
> + .write = oxp_platform_write,
> +};
> +
> +static const struct hwmon_chip_info oxp_ec_chip_info = {
> + .ops = &oxp_ec_hwmon_ops,
> + .info = oxp_platform_sensors,
> +};
> +
> +/* Initialization logic */
> +static int oxp_platform_probe(struct platform_device *pdev)
> +{
> + const struct dmi_system_id *dmi_entry;
> + struct device *dev = &pdev->dev;
> + struct device *hwdev;
> +
> + /* Have to check for AMD processor here because DMI strings are the
> + * same between Intel and AMD boards, the only way to tell them appart
> + * is the CPU.
> + * Intel boards seem to have different EC registers and values to
> + * read/write.
> + */
/*
* Please use standard multi-line comments
*/
> + dmi_entry = dmi_first_match(dmi_table);
> + if (!dmi_entry || boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
> + return -ENODEV;
> +
> + hwdev = devm_hwmon_device_register_with_info(dev, "oxpec", NULL,
> + &oxp_ec_chip_info, NULL);
> +
> + return PTR_ERR_OR_ZERO(hwdev);
> +}
> +
> +static struct platform_driver oxp_platform_driver = {
> + .driver = {
> + .name = "oxp-platform",
> + },
> + .probe = oxp_platform_probe,
> +};
> +
> +static struct platform_device *oxp_platform_device;
> +
> +static int __init oxp_platform_init(void)
> +{
> + oxp_platform_device =
> + platform_create_bundle(&oxp_platform_driver,
> + oxp_platform_probe, NULL, 0, NULL, 0);
> +
> + if (IS_ERR(oxp_platform_device))
> + return PTR_ERR(oxp_platform_device);
Why not PTR_ERR_OR_ZERO() here ?
> +
> + return 0;
> +}
> +
> +static void __exit oxp_platform_exit(void)
> +{
> + platform_device_unregister(oxp_platform_device);
> + platform_driver_unregister(&oxp_platform_driver);
> +}
> +
> +MODULE_DEVICE_TABLE(dmi, dmi_table);
> +module_init(oxp_platform_init);
> +module_exit(oxp_platform_exit);
Can you use module_platform_driver() instead ?
> +
> +MODULE_AUTHOR("Joaquín Ignacio Aramendía <samsagax@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Platform driver that handles EC sensors of OneXPlayer devices");
> +MODULE_LICENSE("GPL");
> --
> 2.38.1
>
