Re: [PATCH v2] hwmon: add Corsair PSU HID controller driver

From: Guenter Roeck
Date: Mon Oct 26 2020 - 11:25:23 EST


On Mon, Oct 26, 2020 at 07:08:07AM +0100, Wilken Gottwalt wrote:
> The Corsair digital power supplies of the series RMi, HXi and AXi
> include a small micro-controller with a lot of sensors attached. It can
> be accessed by an USB connector from the outside.
>
> This micro-controller provides its data by a simple proprietary USB HID
> protocol. The data provided are temperatures, current and voltage levels,
> power used, uptimes, fan speed and a lot more. It is also possible to
> configure the PSU (fan mode, mono/multi-rail, over current protection).
>
> This driver provides access to the sensors/statistics of the RMi and HXi
> series power supplies. It does not support configuring these devices,
> because there would be many ways to misconfigure or even damage the PSU.
>
> This patch adds:
> - hwmon driver corsair-psu
> - hwmon documentation
> - updates MAINTAINERS
>
> Signed-off-by: Wilken Gottwalt <wilken.gottwalt@xxxxxxxxxxx>
> ---
> Changes in v2:
> - changed comments to hwmon style comments

This is not "hwmon style". Please read and follow
Documentation/process/coding-style.rst.

> - simplified some switches
> - removed redundant code
> - removed misuse of EIO
> - changed a todo to a proper explanation
> - changed debugfs, which
> +do not fit into the hwmon class.
> +
> +Debugfs entries
> +---------------
> +
> +======================= ========================================================
> +uptime Current uptime of the psu
> +uptime_total Total uptime of the psu
> +vendor Vendor name of the psu
> +product Product name of the psu
> +======================= ========================================================
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 750d3a975d82..b2a8a47f742a 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -48,6 +48,7 @@ Hardware Monitoring Kernel Drivers
> bt1-pvt
> coretemp
> corsair-cpro
> + corsair-psu
> da9052
> da9055
> dell-smm-hwmon
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 867157311dc8..d1a4e54b21ef 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4478,6 +4478,13 @@ L: linux-hwmon@xxxxxxxxxxxxxxx
> S: Maintained
> F: drivers/hwmon/corsair-cpro.c
>
> +CORSAIR-PSU HARDWARE MONITOR DRIVER
> +M: Wilken Gottwalt <wilken.gottwalt@xxxxxxxxxxx>
> +L: linux-hwmon@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: Documentation/hwmon/corsair-psu.rst
> +F: drivers/hwmon/corsair-psu.c
> +
> COSA/SRP SYNC SERIAL DRIVER
> M: Jan "Yenya" Kasprzak <kas@xxxxxxxxxx>
> S: Maintained
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 8dc28b26916e..2a38963f0cc6 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -449,6 +449,19 @@ config SENSORS_CORSAIR_CPRO
> This driver can also be built as a module. If so, the module
> will be called corsair-cpro.
>
> +config SENSORS_CORSAIR_PSU
> + tristate "Corsair PSU HID controller"
> + depends on HID
> + help
> + If you say yes here you get support for Corsair PSUs with a HID
> + interface.
> + Currently this driver supports the (RM/HX)550, (RM/HX)650i,
> + (RM/HX)750i, (RM/HX)850i, (RM/HX)1000i and HX1200i power supplies
> + by Corsair.
> +
> + This driver can also be built as a module. If so, the module
> + will be called corsair-psu.
> +
> config SENSORS_DRIVETEMP
> tristate "Hard disk drives with temperature sensors"
> depends on SCSI && ATA
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index a8f4b35b136b..2651bcc7ae5f 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -57,6 +57,7 @@ obj-$(CONFIG_SENSORS_AXI_FAN_CONTROL) += axi-fan-control.o
> obj-$(CONFIG_SENSORS_BT1_PVT) += bt1-pvt.o
> obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o
> obj-$(CONFIG_SENSORS_CORSAIR_CPRO) += corsair-cpro.o
> +obj-$(CONFIG_SENSORS_CORSAIR_PSU) += corsair-psu.o
> obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o
> obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o
> obj-$(CONFIG_SENSORS_DELL_SMM) += dell-smm-hwmon.o
> diff --git a/drivers/hwmon/corsair-psu.c b/drivers/hwmon/corsair-psu.c
> new file mode 100644
> index 000000000000..53c92197011d
> --- /dev/null
> +++ b/drivers/hwmon/corsair-psu.c
> @@ -0,0 +1,631 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * corsair-psu.c - Linux driver for Corsair power supplies with HID sensors interface
> + * Copyright (C) 2020 Wilken Gottwalt <wilken.gottwalt@xxxxxxxxxxx>
> + */
> +
> +#include <linux/completion.h>
> +#include <linux/debugfs.h>
> +#include <linux/errno.h>
> +#include <linux/hid.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +
> +/*
> + * Corsair protocol for PSUs
> + *
> + * message size = 64 bytes (request and response, little endian)
> + * request:
> + * [length][command][param0][param1][paramX]...
> + * reply:
> + * [echo of length][echo of command][data0][data1][dataX]...
> + *
> + * - commands are byte sized opcodes
> + * - length is the sum of all bytes of the commands/params
> + * - the micro-controller of most of these PSUs support concatenation in the request and reply,
> + * but it is better to not rely on this (it is also hard to parse)
> + * - the driver uses raw events to be accessible from userspace (though this is not really
> + * supported, it is just there for convenience, may be removed in the future)
> + * - a reply always start with the length and command in the same order the request used it
> + * - length of the reply data is specific to the command used
> + * - some of the commands work on a rail and can be switched to a specific rail (0 = 12v,
> + * 1 = 5v, 2 = 3.3v)
> + * - the format of the init command 0xFE is swapped length/command bytes
> + * - parameter bytes amount and values are specific to the command (rail setting is the only
> + * for now that uses non-zero values)
> + * - there are much more commands, especially for configuring the device, but they are not
> + * supported because a wrong command/length can lockup the micro-controller
> + * - the driver supports debugfs for values not fitting into the hwmon class
> + * - not every device class (HXi, RMi or AXi) supports all commands
> + * - it is a pure sensors reading driver (will not support configuring)
> + */
> +
> +#define DRIVER_NAME "corsair-psu"
> +
> +#define REPLY_SIZE 16 /* max length of a reply to a single command */
> +#define CMD_BUFFER_SIZE 64
> +#define CMD_TIMEOUT_MS 250
> +#define SECONDS_PER_HOUR (60 * 60)
> +#define SECONDS_PER_DAY (SECONDS_PER_HOUR * 24)
> +
> +#define PSU_CMD_SELECT_RAIL 0x00 /* expects length 2 */
> +#define PSU_CMD_IN_VOLTS 0x88 /* the rest of the commands expect length 3 */
> +#define PSU_CMD_IN_AMPS 0x89
> +#define PSU_CMD_RAIL_OUT_VOLTS 0x8B
> +#define PSU_CMD_RAIL_AMPS 0x8C
> +#define PSU_CMD_TEMP0 0x8D
> +#define PSU_CMD_TEMP1 0x8E
> +#define PSU_CMD_FAN 0x90
> +#define PSU_CMD_RAIL_WATTS 0x96
> +#define PSU_CMD_VEND_STR 0x99
> +#define PSU_CMD_PROD_STR 0x9A
> +#define PSU_CMD_TOTAL_WATTS 0xEE
> +#define PSU_CMD_TOTAL_UPTIME 0xD1
> +#define PSU_CMD_UPTIME 0xD2
> +#define PSU_CMD_INIT 0xFE
> +
> +#define L_IN_VOLTS "v_in"
> +#define L_OUT_VOLTS_12V "v_out +12v"
> +#define L_OUT_VOLTS_5V "v_out +5v"
> +#define L_OUT_VOLTS_3_3V "v_out +3.3v"
> +#define L_IN_AMPS "curr in"
> +#define L_AMPS_12V "curr +12v"
> +#define L_AMPS_5V "curr +5v"
> +#define L_AMPS_3_3V "curr +3.3v"
> +#define L_FAN "psu fan"
> +#define L_TEMP0 "vrm temp"
> +#define L_TEMP1 "case temp"
> +#define L_WATTS "power total"
> +#define L_WATTS_12V "power +12v"
> +#define L_WATTS_5V "power +5v"
> +#define L_WATTS_3_3V "power +3.3v"
> +
> +struct corsairpsu_data {
> + struct hid_device *hdev;
> + struct device *hwmon_dev;
> + struct dentry *debugfs;
> + struct completion wait_completion;
> + struct mutex lock; /* for locking access to cmd_buffer */
> + u8 *cmd_buffer;
> + char vendor[REPLY_SIZE];
> + char product[REPLY_SIZE];
> +};
> +
> +/* some values are SMBus LINEAR11 data which need a conversion */
> +static int corsairpsu_linear11_to_int(const u16 val)
> +{
> + int exp = val >> 0x0B;
> + int mant = val & 0x7FF;
> + int i;
> +
> + if (exp > 0x0F)
> + exp -= 0x20;
> + if (mant > 0x3FF)
> + mant -= 0x800;
> + if ((mant & 0x01) == 1)
> + ++mant;
> + if (exp < 0) {
> + for (i = 0; i < -exp; ++i)
> + mant /= 2;
> + } else {
> + for (i = 0; i < exp; ++i)
> + mant *= 2;
> + }
> +
> + return mant;
> +}
> +
> +static int corsairpsu_usb_cmd(struct corsairpsu_data *priv, u8 p0, u8 p1, u8 p2, void *data)
> +{
> + unsigned long time;
> + int ret;
> +
> + memset(priv->cmd_buffer, 0, CMD_BUFFER_SIZE);
> + priv->cmd_buffer[0] = p0;
> + priv->cmd_buffer[1] = p1;
> + priv->cmd_buffer[2] = p2;
> +
> + reinit_completion(&priv->wait_completion);
> +
> + ret = hid_hw_output_report(priv->hdev, priv->cmd_buffer, CMD_BUFFER_SIZE);
> + if (ret < 0)
> + return ret;
> +
> + time = wait_for_completion_timeout(&priv->wait_completion,
> + msecs_to_jiffies(CMD_TIMEOUT_MS));
> + if (!time)
> + return -ETIMEDOUT;
> +
> + /* at the start of the reply is an echo of the send command/length in the same order it */
> + /* was send, not every command is supported on every device class, if a command is not */
> + /* supported, the length value in the reply is okay, but the command value is set to 0 */

Please read and follow Documentation/process/coding-style.rst
for multi-line comments.

> + if (p0 != priv->cmd_buffer[0] || p1 != priv->cmd_buffer[1])
> + return -EOPNOTSUPP;
> +
> + if (data)
> + memcpy(data, priv->cmd_buffer + 2, REPLY_SIZE);
> +
> + return 0;
> +}
> +
> +static int corsairpsu_init(struct corsairpsu_data *priv)
> +{
> + /* PSU_CMD_INIT uses swapped length/command and expects 2 parameter bytes, this command */
> + /* actually generates a reply, but we don't need it */
> +
> + return corsairpsu_usb_cmd(priv, PSU_CMD_INIT, 3, 0, NULL);
> +}
> +
> +static int corsairpsu_fwinfo(struct corsairpsu_data *priv)
> +{
> + int ret;
> +
> + ret = corsairpsu_usb_cmd(priv, 3, PSU_CMD_VEND_STR, 0, priv->vendor);
> + if (ret < 0)
> + return ret;
> +
> + ret = corsairpsu_usb_cmd(priv, 3, PSU_CMD_PROD_STR, 0, priv->product);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int corsairpsu_request(struct corsairpsu_data *priv, u8 cmd, u8 rail, void *data)
> +{
> + int ret;
> +
> + mutex_lock(&priv->lock);
> + switch (cmd) {
> + case PSU_CMD_RAIL_OUT_VOLTS:
> + case PSU_CMD_RAIL_AMPS:
> + case PSU_CMD_RAIL_WATTS:
> + ret = corsairpsu_usb_cmd(priv, 2, PSU_CMD_SELECT_RAIL, rail, NULL);
> + if (ret < 0)
> + goto cmd_fail;
> + fallthrough;
> + default:
> + ret = corsairpsu_usb_cmd(priv, 3, cmd, 0, data);
> + break;
> + }
...
break;
default:
break;
}

ret = corsairpsu_usb_cmd(priv, 3, cmd, 0, data);

> +
> +cmd_fail:
> + mutex_unlock(&priv->lock);
> + return ret;
> +}
> +
> +static int corsairpsu_get_value(struct corsairpsu_data *priv, u8 cmd, u8 rail, u32 *val)
> +{
> + u8 data[REPLY_SIZE];
> + int ret;
> +
> + ret = corsairpsu_request(priv, cmd, rail, data);
> + if (ret < 0)
> + return ret;
> +
> + switch (cmd) {
> + case PSU_CMD_IN_VOLTS:
> + case PSU_CMD_IN_AMPS:
> + case PSU_CMD_RAIL_OUT_VOLTS:
> + case PSU_CMD_RAIL_AMPS:
> + case PSU_CMD_TEMP0:
> + case PSU_CMD_TEMP1:
> + *val = (data[1] << 8) + data[0];

Please use a local variable to cache the raw value.

> + *val = corsairpsu_linear11_to_int(*val) * 1000;

Something is wrong here. val is a pointer to u32.
corsairpsu_linear11_to_int(), however, returns an int.
The implementation of corsairpsu_linear11_to_int() suggests
that the value can be negative. Either it can be negative
and needs to be returned as such, or it can't and
corsairpsu_linear11_to_int() should only return unsigned
values.

Also, this can overflow: corsairpsu_linear11_to_int()
can return a value larger that (MAXINT / 1000).

> + break;
> + case PSU_CMD_FAN:
> + /* this value is best guess, so the calculated value could be wrong, it is hard */
> + /* to ge the fan to spin in these semi-passive power supplies, which need a */
> + /* quite high load to do so */
> + *val = (data[0] << 8) + data[1];
> + break;
> + case PSU_CMD_RAIL_WATTS:
> + case PSU_CMD_TOTAL_WATTS:
> + *val = (data[1] << 8) + data[0];

Same here.

> + *val = corsairpsu_linear11_to_int(*val) * 1000000;

Same problems as above, and overflow is even more likely.

> + break;
> + case PSU_CMD_TOTAL_UPTIME:
> + case PSU_CMD_UPTIME:
> + *val = (data[3] << 24) + (data[2] << 16) + (data[1] << 8) + data[0];
> + break;
> + default:
> + ret = -EOPNOTSUPP;
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static umode_t corsairpsu_hwmon_ops_is_visible(const void *data, enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + if (type == hwmon_temp && (attr == hwmon_temp_input || attr == hwmon_temp_label))
> + return 0444;
> + else if (type == hwmon_fan && (attr == hwmon_fan_input || attr == hwmon_fan_label))
> + return 0444;
> + else if (type == hwmon_power && (attr == hwmon_power_input || attr == hwmon_power_label))
> + return 0444;
> + else if (type == hwmon_in && (attr == hwmon_in_input || attr == hwmon_in_label))
> + return 0444;
> + else if (type == hwmon_curr && (attr == hwmon_curr_input || attr == hwmon_curr_label))
> + return 0444;
> +
> + return 0;
> +}
> +
> +static int corsairpsu_hwmon_ops_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
> + int channel, long *val)
> +{
> + struct corsairpsu_data *priv = dev_get_drvdata(dev);
> + u32 tmp;
> + int ret;
> +
> + if (type == hwmon_temp && attr == hwmon_temp_input && channel < 2) {
> + ret = corsairpsu_get_value(priv, channel ? PSU_CMD_TEMP1 : PSU_CMD_TEMP0, channel,
> + &tmp);
> + } else if (type == hwmon_fan && attr == hwmon_fan_input) {
> + ret = corsairpsu_get_value(priv, PSU_CMD_FAN, 0, &tmp);
> + } else if (type == hwmon_power && attr == hwmon_power_input) {
> + switch (channel) {
> + case 0:
> + ret = corsairpsu_get_value(priv, PSU_CMD_TOTAL_WATTS, 0, &tmp);
> + break;
> + case 1:
> + case 2:
> + case 3:

What is the problem with the following ?

case 1...3:

> + ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_WATTS, channel - 1, &tmp);
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> + } else if (type == hwmon_in && attr == hwmon_in_input) {
> + switch (channel) {
> + case 0:
> + ret = corsairpsu_get_value(priv, PSU_CMD_IN_VOLTS, 0, &tmp);
> + break;
> + case 1:
> + case 2:
> + case 3:
> + ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_OUT_VOLTS, channel - 1, &tmp);
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> + } else if (type == hwmon_curr && attr == hwmon_curr_input) {
> + switch (channel) {
> + case 0:
> + ret = corsairpsu_get_value(priv, PSU_CMD_IN_AMPS, 0, &tmp);
> + break;
> + case 1:
> + case 2:
> + case 3:
> + ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_AMPS, channel - 1, &tmp);
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> + } else {
> + return -EOPNOTSUPP;
> + }
> +
> + if (ret < 0)
> + return ret;
> + *val = tmp;
> +
> + return 0;
> +}
> +
> +static int corsairpsu_hwmon_ops_read_string(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, const char **str)
> +{
> + if (type == hwmon_temp && attr == hwmon_temp_label) {
> + *str = channel ? L_TEMP1 : L_TEMP0;
> + return 0;
> + } else if (type == hwmon_fan && attr == hwmon_fan_label) {
> + *str = L_FAN;
> + return 0;
> + } else if (type == hwmon_power && attr == hwmon_power_label) {
> + switch (channel) {
> + case 0:
> + *str = L_WATTS;
> + return 0;
> + case 1:
> + *str = L_WATTS_12V;
> + return 0;
> + case 2:
> + *str = L_WATTS_5V;
> + return 0;
> + case 3:
> + *str = L_WATTS_3_3V;
> + return 0;
> + default:
> + break;
> + }

Just a thought for those:

const char *watts[] = { L_WATTS, L_WATTS_12V, L_WATTS_5V, L_WATTS_3_3V };

*str = watts[channel];
return 0;

> + } else if (type == hwmon_in && attr == hwmon_in_label) {
> + switch (channel) {
> + case 0:
> + *str = L_IN_VOLTS;
> + return 0;
> + case 1:
> + *str = L_OUT_VOLTS_12V;
> + return 0;
> + case 2:
> + *str = L_OUT_VOLTS_5V;
> + return 0;
> + case 3:
> + *str = L_OUT_VOLTS_3_3V;
> + return 0;
> + default:
> + break;
> + }
> + } else if (type == hwmon_curr && attr == hwmon_curr_label) {
> + switch (channel) {
> + case 0:
> + *str = L_IN_AMPS;
> + return 0;
> + case 1:
> + *str = L_AMPS_12V;
> + return 0;
> + case 2:
> + *str = L_AMPS_5V;
> + return 0;
> + case 3:
> + *str = L_AMPS_3_3V;
> + return 0;
> + default:
> + break;
> + }
> + }
> +
> + return -EOPNOTSUPP;
> +}
> +
> +static const struct hwmon_ops corsairpsu_hwmon_ops = {
> + .is_visible = corsairpsu_hwmon_ops_is_visible,
> + .read = corsairpsu_hwmon_ops_read,
> + .read_string = corsairpsu_hwmon_ops_read_string,
> +};
> +
> +static const struct hwmon_channel_info *corsairpsu_info[] = {
> + HWMON_CHANNEL_INFO(chip,
> + HWMON_C_REGISTER_TZ),
> + HWMON_CHANNEL_INFO(temp,
> + HWMON_T_INPUT | HWMON_T_LABEL,
> + HWMON_T_INPUT | HWMON_T_LABEL),
> + HWMON_CHANNEL_INFO(fan,
> + HWMON_F_INPUT | HWMON_F_LABEL),
> + HWMON_CHANNEL_INFO(power,
> + HWMON_P_INPUT | HWMON_P_LABEL,
> + HWMON_P_INPUT | HWMON_P_LABEL,
> + HWMON_P_INPUT | HWMON_P_LABEL,
> + HWMON_P_INPUT | HWMON_P_LABEL),
> + HWMON_CHANNEL_INFO(in,
> + HWMON_I_INPUT | HWMON_I_LABEL,
> + HWMON_I_INPUT | HWMON_I_LABEL,
> + HWMON_I_INPUT | HWMON_I_LABEL,
> + HWMON_I_INPUT | HWMON_I_LABEL),
> + HWMON_CHANNEL_INFO(curr,
> + HWMON_C_INPUT | HWMON_C_LABEL,
> + HWMON_C_INPUT | HWMON_C_LABEL,
> + HWMON_C_INPUT | HWMON_C_LABEL,
> + HWMON_C_INPUT | HWMON_C_LABEL),
> + NULL
> +};
> +
> +static const struct hwmon_chip_info corsairpsu_chip_info = {
> + .ops = &corsairpsu_hwmon_ops,
> + .info = corsairpsu_info,
> +};
> +
> +#ifdef CONFIG_DEBUG_FS
> +
> +static void print_uptime(struct seq_file *seqf, u8 cmd)
> +{
> + struct corsairpsu_data *priv = seqf->private;
> + u32 val;
> + int ret;
> +
> + ret = corsairpsu_get_value(priv, cmd, 0, &val);
> + if (ret < 0) {
> + seq_puts(seqf, "N/A\n");
> + return;
> + }
> +
> + if (val > SECONDS_PER_DAY) {
> + seq_printf(seqf, "%d day(s), %02d:%02d:%02d\n", val / SECONDS_PER_DAY,
> + val % SECONDS_PER_DAY / SECONDS_PER_HOUR, val % SECONDS_PER_HOUR / 60,
> + val % 60);
> + return;
> + }
> +
> + seq_printf(seqf, "%02d:%02d:%02d\n", val % SECONDS_PER_DAY / SECONDS_PER_HOUR,
> + val % SECONDS_PER_HOUR / 60, val % 60);
> +}
> +
> +static int uptime_show(struct seq_file *seqf, void *unused)
> +{
> + print_uptime(seqf, PSU_CMD_UPTIME);
> +
> + return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(uptime);
> +
> +static int uptime_total_show(struct seq_file *seqf, void *unused)
> +{
> + print_uptime(seqf, PSU_CMD_TOTAL_UPTIME);
> +
> + return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(uptime_total);
> +
> +static int vendor_show(struct seq_file *seqf, void *unused)
> +{
> + struct corsairpsu_data *priv = seqf->private;
> +
> + seq_printf(seqf, "%s\n", priv->vendor);
> +
> + return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(vendor);
> +
> +static int product_show(struct seq_file *seqf, void *unused)
> +{
> + struct corsairpsu_data *priv = seqf->private;
> +
> + seq_printf(seqf, "%s\n", priv->product);
> +
> + return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(product);
> +
> +static void corsairpsu_debugfs_init(struct corsairpsu_data *priv)
> +{
> + char name[32];
> +
> + scnprintf(name, sizeof(name), "%s-%s", DRIVER_NAME, dev_name(&priv->hdev->dev));
> +
> + priv->debugfs = debugfs_create_dir(name, NULL);
> + debugfs_create_file("uptime", 0444, priv->debugfs, priv, &uptime_fops);
> + debugfs_create_file("uptime_total", 0444, priv->debugfs, priv, &uptime_total_fops);
> + debugfs_create_file("vendor", 0444, priv->debugfs, priv, &vendor_fops);
> + debugfs_create_file("product", 0444, priv->debugfs, priv, &product_fops);
> +}
> +
> +static void corsairpsu_debugfs_remove(struct corsairpsu_data *priv)
> +{
> + debugfs_remove_recursive(priv->debugfs);
> +}

If debugfs is not enabled, debugfs_remove_recursive() is a dummy.
That means it can be called unconditionally from the remove function,
and corsairpsu_debugfs_remove() is unnecessary.

> +
> +#else
> +
> +static void corsairpsu_debugfs_init(struct corsairpsu_data *priv)
> +{
> +}
> +
> +static void corsairpsu_debugfs_remove(struct corsairpsu_data *priv)
> +{
> +}
> +
> +#endif
> +
> +static int corsairpsu_probe(struct hid_device *hdev, const struct hid_device_id *id)
> +{
> + struct corsairpsu_data *priv;
> + int ret;
> +
> + priv = devm_kzalloc(&hdev->dev, sizeof(struct corsairpsu_data), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->cmd_buffer = devm_kmalloc(&hdev->dev, CMD_BUFFER_SIZE, GFP_KERNEL);
> + if (!priv->cmd_buffer)
> + return -ENOMEM;
> +
> + ret = hid_parse(hdev);
> + if (ret)
> + return ret;
> +
> + ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
> + if (ret)
> + return ret;
> +
> + ret = hid_hw_open(hdev);
> + if (ret)
> + goto fail_and_stop;
> +
> + priv->hdev = hdev;
> + hid_set_drvdata(hdev, priv);
> + mutex_init(&priv->lock);
> + init_completion(&priv->wait_completion);
> +
> + hid_device_io_start(hdev);
> +
> + ret = corsairpsu_init(priv);
> + if (ret < 0) {
> + dev_err(&hdev->dev, "unable to initialize device (%d)\n", ret);
> + goto fail_and_stop;
> + }
> +
> + ret = corsairpsu_fwinfo(priv);
> + if (ret < 0) {
> + dev_err(&hdev->dev, "unable to query firmware (%d)\n", ret);
> + goto fail_and_stop;
> + }
> +
> + priv->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "corsairpsu", priv,
> + &corsairpsu_chip_info, 0);
> +
> + if (IS_ERR(priv->hwmon_dev)) {
> + ret = PTR_ERR(priv->hwmon_dev);
> + goto fail_and_close;
> + }
> +
> + corsairpsu_debugfs_init(priv);
> +
> + return 0;
> +
> +fail_and_close:
> + hid_hw_close(hdev);
> +fail_and_stop:
> + hid_hw_stop(hdev);
> + return ret;
> +}
> +
> +static void corsairpsu_remove(struct hid_device *hdev)
> +{
> + struct corsairpsu_data *priv = hid_get_drvdata(hdev);
> +
> + corsairpsu_debugfs_remove(priv);
> + hwmon_device_unregister(priv->hwmon_dev);
> + hid_hw_close(hdev);
> + hid_hw_stop(hdev);
> +}
> +
> +static int corsairpsu_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data,
> + int size)
> +{
> + struct corsairpsu_data *priv = hid_get_drvdata(hdev);
> +
> + if (completion_done(&priv->wait_completion))
> + return 0;
> +
> + memcpy(priv->cmd_buffer, data, min(CMD_BUFFER_SIZE, size));
> + complete(&priv->wait_completion);
> +
> + return 0;
> +}
> +
> +static const struct hid_device_id corsairpsu_idtable[] = {
> + { HID_USB_DEVICE(0x1b1c, 0x1c03) }, /* Corsair HX550i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c04) }, /* Corsair HX650i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c05) }, /* Corsair HX750i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c06) }, /* Corsair HX850i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c07) }, /* Corsair HX1000i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c08) }, /* Corsair HX1200i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c09) }, /* Corsair RM550i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c0a) }, /* Corsair RM650i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c0b) }, /* Corsair RM750i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c0c) }, /* Corsair RM850i */
> + { HID_USB_DEVICE(0x1b1c, 0x1c0d) }, /* Corsair RM1000i */
> + { },
> +};
> +MODULE_DEVICE_TABLE(hid, corsairpsu_idtable);
> +
> +static struct hid_driver corsairpsu_driver = {
> + .name = DRIVER_NAME,
> + .id_table = corsairpsu_idtable,
> + .probe = corsairpsu_probe,
> + .remove = corsairpsu_remove,
> + .raw_event = corsairpsu_raw_event,
> +};
> +module_hid_driver(corsairpsu_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Wilken Gottwalt <wilken.gottwalt@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Linux driver for Corsair power supplies with HID sensors interface");
> --
> 2.29.0
>