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Message-ID: <CAOoeyxX=A5o5PhxpniPwPgMCBv1VwMstt=wXCxHiGPF59gm5wQ@mail.gmail.com>
Date: Fri, 25 Oct 2024 23:22:10 +0800
From: Ming Yu <a0282524688@...il.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Kalesh Anakkur Purayil <kalesh-anakkur.purayil@...adcom.com>, tmyu0@...oton.com, lee@...nel.org,
linus.walleij@...aro.org, brgl@...ev.pl, andi.shyti@...nel.org,
mkl@...gutronix.de, mailhol.vincent@...adoo.fr, andrew+netdev@...n.ch,
davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
wim@...ux-watchdog.org, jdelvare@...e.com, jic23@...nel.org, lars@...afoo.de,
ukleinek@...nel.org, alexandre.belloni@...tlin.com,
linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
linux-i2c@...r.kernel.org, linux-can@...r.kernel.org, netdev@...r.kernel.org,
linux-watchdog@...r.kernel.org, linux-hwmon@...r.kernel.org,
linux-iio@...r.kernel.org, linux-pwm@...r.kernel.org,
linux-rtc@...r.kernel.org
Subject: Re: [PATCH v1 6/9] hwmon: Add Nuvoton NCT6694 HWMON support
Dear Guenter,
Thank you for your comments.
Guenter Roeck <linux@...ck-us.net> 於 2024年10月24日 週四 下午10:53寫道：
>
> On 10/24/24 02:20, Kalesh Anakkur Purayil wrote:
> > On Thu, Oct 24, 2024 at 2:33 PM Ming Yu <a0282524688@...il.com> wrote:
> >>
> >> This driver supports Hardware monitor functionality for NCT6694 MFD
> >> device based on USB interface.
> >>
> >> Signed-off-by: Ming Yu <tmyu0@...oton.com>
> >> ---
> >> MAINTAINERS | 1 +
> >> drivers/hwmon/Kconfig | 10 +
> >> drivers/hwmon/Makefile | 1 +
> >> drivers/hwmon/nct6694-hwmon.c | 407 ++++++++++++++++++++++++++++++++++
> >> 4 files changed, 419 insertions(+)
> >> create mode 100644 drivers/hwmon/nct6694-hwmon.c
> >>
> >> diff --git a/MAINTAINERS b/MAINTAINERS
> >> index 63387c0d4ab6..2aa87ad84156 100644
> >> --- a/MAINTAINERS
> >> +++ b/MAINTAINERS
> >> @@ -16439,6 +16439,7 @@ M: Ming Yu <tmyu0@...oton.com>
> >> L: linux-kernel@...r.kernel.org
> >> S: Supported
> >> F: drivers/gpio/gpio-nct6694.c
> >> +F: drivers/hwmon/nct6694-hwmon.c
> >> F: drivers/i2c/busses/i2c-nct6694.c
> >> F: drivers/mfd/nct6694.c
> >> F: drivers/net/can/nct6694_canfd.c
> >> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> >> index 08a3c863f80a..740e4afe6582 100644
> >> --- a/drivers/hwmon/Kconfig
> >> +++ b/drivers/hwmon/Kconfig
> >> @@ -1625,6 +1625,16 @@ config SENSORS_NCT6683
> >> This driver can also be built as a module. If so, the module
> >> will be called nct6683.
> >>
> >> +config SENSORS_NCT6694
> >> + tristate "Nuvoton NCT6694 Hardware Monitor support"
> >> + depends on MFD_NCT6694
> >> + help
> >> + Say Y here to support Nuvoton NCT6694 hardware monitoring
> >> + functionality.
> >> +
> >> + This driver can also be built as a module. If so, the module
> >> + will be called nct6694-hwmon.
> >> +
> >> config SENSORS_NCT6775_CORE
> >> tristate
> >> select REGMAP
> >> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> >> index 9554d2fdcf7b..729961176d00 100644
> >> --- a/drivers/hwmon/Makefile
> >> +++ b/drivers/hwmon/Makefile
> >> @@ -167,6 +167,7 @@ obj-$(CONFIG_SENSORS_MLXREG_FAN) += mlxreg-fan.o
> >> obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o
> >> obj-$(CONFIG_SENSORS_MR75203) += mr75203.o
> >> obj-$(CONFIG_SENSORS_NCT6683) += nct6683.o
> >> +obj-$(CONFIG_SENSORS_NCT6694) += nct6694-hwmon.o
> >> obj-$(CONFIG_SENSORS_NCT6775_CORE) += nct6775-core.o
> >> nct6775-objs := nct6775-platform.o
> >> obj-$(CONFIG_SENSORS_NCT6775) += nct6775.o
> >> diff --git a/drivers/hwmon/nct6694-hwmon.c b/drivers/hwmon/nct6694-hwmon.c
> >> new file mode 100644
> >> index 000000000000..7d7d22a650b0
> >> --- /dev/null
> >> +++ b/drivers/hwmon/nct6694-hwmon.c
> >> @@ -0,0 +1,407 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * Nuvoton NCT6694 HWMON driver based on USB interface.
> >> + *
> >> + * Copyright (C) 2024 Nuvoton Technology Corp.
> >> + */
> >> +
> >> +#include <linux/slab.h>
> >> +#include <linux/kernel.h>
> >> +#include <linux/module.h>
> >> +#include <linux/hwmon.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/mfd/nct6694.h>
> >> +
> >> +#define DRVNAME "nct6694-hwmon"
> >> +
> >> +/* Host interface */
> >> +#define REQUEST_RPT_MOD 0xFF
> >> +#define REQUEST_HWMON_MOD 0x00
> >> +
> >> +/* Report Channel */
> >> +#define HWMON_FIN_IDX(x) (0x50 + ((x) * 2))
> >> +#define HWMON_FIN_STS(x) (0x6E + (x))
> >> +#define HWMON_PWM_IDX(x) (0x70 + (x))
> >> +
> >> +/* Message Channel*/
> >> +/* Command 00h */
> >> +#define REQUEST_HWMON_CMD0_LEN 0x40
> >> +#define REQUEST_HWMON_CMD0_OFFSET 0x0000 /* OFFSET = SEL|CMD */
> >> +#define HWMON_FIN_EN(x) (0x04 + (x))
> >> +#define HWMON_PWM_FREQ_IDX(x) (0x30 + (x))
> >> +/* Command 02h */
> >> +#define REQUEST_HWMON_CMD2_LEN 0x90
> >> +#define REQUEST_HWMON_CMD2_OFFSET 0x0002 /* OFFSET = SEL|CMD */
> >> +#define HWMON_SMI_CTRL_IDX 0x00
> >> +#define HWMON_FIN_LIMIT_IDX(x) (0x70 + ((x) * 2))
> >> +#define HWMON_CMD2_HYST_MASK 0x1F
> >> +/* Command 03h */
> >> +#define REQUEST_HWMON_CMD3_LEN 0x08
> >> +#define REQUEST_HWMON_CMD3_OFFSET 0x0003 /* OFFSET = SEL|CMD */
> >> +
> >> +struct nct6694_hwmon_data {
> >> + struct nct6694 *nct6694;
> >> +
> >> + /* Make sure read & write commands are consecutive */
> >> + struct mutex hwmon_lock;
> >> +};
> >> +
> >> +#define NCT6694_HWMON_FAN_CONFIG (HWMON_F_ENABLE | HWMON_F_INPUT | \
> >> + HWMON_F_MIN | HWMON_F_MIN_ALARM)
> >> +#define NCT6694_HWMON_PWM_CONFIG (HWMON_PWM_INPUT | HWMON_PWM_FREQ)
> >> +
> >> +static const struct hwmon_channel_info *nct6694_info[] = {
> >> + HWMON_CHANNEL_INFO(fan,
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN0 */
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN1 */
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN2 */
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN3 */
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN4 */
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN5 */
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN6 */
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN7 */
> >> + NCT6694_HWMON_FAN_CONFIG, /* FIN8 */
> >> + NCT6694_HWMON_FAN_CONFIG), /* FIN9 */
> >> +
> >> + HWMON_CHANNEL_INFO(pwm,
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM0 */
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM1 */
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM2 */
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM3 */
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM4 */
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM5 */
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM6 */
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM7 */
> >> + NCT6694_HWMON_PWM_CONFIG, /* PWM8 */
> >> + NCT6694_HWMON_PWM_CONFIG), /* PWM9 */
> >> + NULL
> >> +};
> >> +
> >> +static int nct6694_fan_read(struct device *dev, u32 attr, int channel,
> >> + long *val)
> >> +{
> >> + struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
> >> + unsigned char buf[2];
> >> + int ret;
> >> +
> >> + switch (attr) {
> >> + case hwmon_fan_enable:
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD0_OFFSET,
> >> + REQUEST_HWMON_CMD0_LEN,
> >> + HWMON_FIN_EN(channel / 8),
> >> + 1, buf);
> >> + if (ret)
> >> + return -EINVAL;
> >> +
> >> + *val = buf[0] & BIT(channel % 8) ? 1 : 0;
> >> +
> >> + break;
> >> +
> >> + case hwmon_fan_input:
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_RPT_MOD,
> >> + HWMON_FIN_IDX(channel), 2, 0,
> >> + 2, buf);
> >> + if (ret)
> >> + return -EINVAL;
> >> +
> >> + *val = (buf[1] | (buf[0] << 8)) & 0xFFFF;
> >> +
> >> + break;
> >> +
> >> + case hwmon_fan_min:
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD2_OFFSET,
> >> + REQUEST_HWMON_CMD2_LEN,
> >> + HWMON_FIN_LIMIT_IDX(channel),
> >> + 2, buf);
> >> + if (ret)
> >> + return -EINVAL;
> >> +
> >> + *val = (buf[1] | (buf[0] << 8)) & 0xFFFF;
> >> +
> >> + break;
> >> +
> >> + case hwmon_fan_min_alarm:
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_RPT_MOD,
> >> + HWMON_FIN_STS(channel / 8),
> >> + 1, 0, 1, buf);
> >> + if (ret)
> >> + return -EINVAL;
> >> +
> >> + *val = buf[0] & BIT(channel % 8);
> >> +
> >> + break;
> >> +
> >> + default:
> >> + return -EOPNOTSUPP;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int nct6694_pwm_read(struct device *dev, u32 attr, int channel,
> >> + long *val)
> >> +{
> >> + struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
> >> + unsigned char buf;
> >> + int ret;
> >> +
> >> + switch (attr) {
> >> + case hwmon_pwm_input:
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_RPT_MOD,
> >> + HWMON_PWM_IDX(channel),
> >> + 1, 0, 1, &buf);
> >> + if (ret)
> >> + return -EINVAL;
> >> +
> >> + *val = buf;
> >> +
> >> + break;
> >> + case hwmon_pwm_freq:
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD0_OFFSET,
> >> + REQUEST_HWMON_CMD0_LEN,
> >> + HWMON_PWM_FREQ_IDX(channel),
> >> + 1, &buf);
> >> + if (ret)
> >> + return -EINVAL;
> >> +
> >> + *val = buf * 25000 / 255;
> >> +
> >> + break;
> >> +
> >> + default:
> >> + return -EOPNOTSUPP;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int nct6694_fan_write(struct device *dev, u32 attr, int channel,
> >> + long val)
> >> +{
> >> + struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
> >> + unsigned char enable_buf[REQUEST_HWMON_CMD0_LEN] = {0};
> > [Kalesh] Please try to maintain RCT order for variable declaration
>
> Ok, but that is already the case here ?
[Ming] Is there anything that needs to be changed?
>
> >> + unsigned char buf[REQUEST_HWMON_CMD2_LEN] = {0};
> >> + u16 fan_val = (u16)val;
> >> + int ret;
> >> +
> >> + switch (attr) {
> >> + case hwmon_fan_enable:
> >> + mutex_lock(&data->hwmon_lock);
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD0_OFFSET,
> >> + REQUEST_HWMON_CMD0_LEN, 0,
> >> + REQUEST_HWMON_CMD0_LEN,
> >> + enable_buf);
> >> + if (ret)
> >> + goto err;
> >> +
> >> + if (val)
> >> + enable_buf[HWMON_FIN_EN(channel / 8)] |= BIT(channel % 8);
> >> + else
> >> + enable_buf[HWMON_FIN_EN(channel / 8)] &= ~BIT(channel % 8);
> >> +
> >> + ret = nct6694_write_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD0_OFFSET,
> >> + REQUEST_HWMON_CMD0_LEN, enable_buf);
> >> + if (ret)
> >> + goto err;
> >> +
> >> + break;
> >> +
> >> + case hwmon_fan_min:
> >> + mutex_lock(&data->hwmon_lock);
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD2_OFFSET,
> >> + REQUEST_HWMON_CMD2_LEN, 0,
> >> + REQUEST_HWMON_CMD2_LEN, buf);
> >> + if (ret)
> >> + goto err;
> >> +
> >> + buf[HWMON_FIN_LIMIT_IDX(channel)] = (u8)((fan_val >> 8) & 0xFF);
> >> + buf[HWMON_FIN_LIMIT_IDX(channel) + 1] = (u8)(fan_val & 0xFF);
> >> + ret = nct6694_write_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD2_OFFSET,
> >> + REQUEST_HWMON_CMD2_LEN, buf);
> >> + if (ret)
> >> + goto err;
> >> +
> >> + break;
> >> +
> >> + default:
> >> + ret = -EOPNOTSUPP;
> > [Kalesh] If you initialize "ret = -EOPNOTSUPP;" during declararion,
> > you can just break from here.
>
> You are missing the point. The lock wasn't acquired here in the first place.
> It is conceptually wrong to acquire a lock in the switch statement and release
> it outside. This patch is a case in point.
[Ming] Okay! I'll acquire the lock before switch() in the next patch.
>
> >> + goto err;
> >> + }
> >> +
> >> +err:
> >> + mutex_unlock(&data->hwmon_lock);
> >> + return ret;
> >> +}
> >> +
> >> +static int nct6694_read(struct device *dev, enum hwmon_sensor_types type,
> >> + u32 attr, int channel, long *val)
> >> +{
> >> + switch (type) {
> >> + case hwmon_fan: /* in RPM */
> >> + return nct6694_fan_read(dev, attr, channel, val);
> >> +
> >> + case hwmon_pwm: /* in value 0~255 */
> >> + return nct6694_pwm_read(dev, attr, channel, val);
> >> +
> >> + default:
> >> + return -EOPNOTSUPP;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int nct6694_write(struct device *dev, enum hwmon_sensor_types type,
> >> + u32 attr, int channel, long val)
> >> +{
> >> + switch (type) {
> >> + case hwmon_fan:
> >> + return nct6694_fan_write(dev, attr, channel, val);
> >> + default:
> >> + return -EOPNOTSUPP;
> >> + }
> > [Kalesh] You can use simple if condition here than a switch like:
> > if (type != hwmon_fan)
> > return -EOPNOTSUPP;
> > return nct6694_fan_write(dev, attr, channel, val);
>
> That is a bit POV. I'd leave that to the developer.
> More important is that the return statements after the switch are unnecessary
> and never reached if each case returns immediately.
[Ming] Okay! I'll drop it in the next patch.
>
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static umode_t nct6694_is_visible(const void *data, enum hwmon_sensor_types type,
> >> + u32 attr, int channel)
> >> +{
> >> + switch (type) {
> >> + case hwmon_fan:
> >> + switch (attr) {
> >> + case hwmon_fan_enable:
> >> + case hwmon_fan_min:
> >> + return 0644;
> > [Kalesh] I think there is no need to leave a new line in between cases
> >> +
> >> + case hwmon_fan_input:
> >> + case hwmon_fan_min_alarm:
> >> + return 0444;
> >> +
> >> + default:
> >> + return 0;
> >> + }
> >> +
> >> + case hwmon_pwm:
> >> + switch (attr) {
> >> + case hwmon_pwm_input:
> >> + case hwmon_pwm_freq:
> >> + return 0444;
> >> + default:
> >> + return 0;
> >> + }
> >> +
> >> + default:
> >> + return 0;
> >> + }
> >> +
> >> + return 0;
> > [Kalesh] This return statement looks redundant as the execution never
> > reaches here. Same comment applies to other functions above as well.
> >> +}
> >> +
> >> +static const struct hwmon_ops nct6694_hwmon_ops = {
> >> + .is_visible = nct6694_is_visible,
> >> + .read = nct6694_read,
> >> + .write = nct6694_write,
> >> +};
> >> +
> >> +static const struct hwmon_chip_info nct6694_chip_info = {
> >> + .ops = &nct6694_hwmon_ops,
> >> + .info = nct6694_info,
> >> +};
> >> +
> >> +static int nct6694_hwmon_init(struct nct6694_hwmon_data *data)
> >> +{
> >> + unsigned char buf[REQUEST_HWMON_CMD2_LEN] = {0};
> >> + int ret;
> >> +
> >> + /* Set Fan input Real Time alarm mode */
> >> + mutex_lock(&data->hwmon_lock);
> >> + ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD2_OFFSET,
> >> + REQUEST_HWMON_CMD2_LEN, 0,
> >> + REQUEST_HWMON_CMD2_LEN, buf);
> >> + if (ret)
> >> + goto err;
> > [Kalesh] It would be better to rename the label as "unlock". Same
> > comment on other functions as well.
>
> The lock is not needed here in the first place. The function is called
> exactly once during initialization.
[Ming] I'll remove the lock in the next patch!
>
> >> +
> >> + buf[HWMON_SMI_CTRL_IDX] = 0x02;
> >> +
> >> + ret = nct6694_write_msg(data->nct6694, REQUEST_HWMON_MOD,
> >> + REQUEST_HWMON_CMD2_OFFSET,
> >> + REQUEST_HWMON_CMD2_LEN, buf);
> >> + if (ret)
> >> + goto err;
> >> +
> >> +err:
> >> + mutex_unlock(&data->hwmon_lock);
> >> + return ret;
> >> +}
> >> +
> >> +static int nct6694_hwmon_probe(struct platform_device *pdev)
> >> +{
> >> + struct nct6694_hwmon_data *data;
> >> + struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
> >> + struct device *hwmon_dev;
> >> + int ret;
> >> +
> >> + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> >> + if (!data)
> >> + return -ENOMEM;
> >> +
> >> + data->nct6694 = nct6694;
> >> + mutex_init(&data->hwmon_lock);
> >> + platform_set_drvdata(pdev, data);
> >> +
> >> + ret = nct6694_hwmon_init(data);
> >> + if (ret)
> >> + return -EIO;
> >> +
> >> + /* Register hwmon device to HWMON framework */
> >> + hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
> >> + "nct6694", data,
> >> + &nct6694_chip_info,
> >> + NULL);
> >> + if (IS_ERR(hwmon_dev)) {
> >> + dev_err(&pdev->dev, "%s: Failed to register hwmon device!\n",
> >> + __func__);
> >> + return PTR_ERR(hwmon_dev);
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static struct platform_driver nct6694_hwmon_driver = {
> >> + .driver = {
> >> + .name = DRVNAME,
> >> + },
> >> + .probe = nct6694_hwmon_probe,
> >> +};
> >> +
> >> +static int __init nct6694_init(void)
> >> +{
> >> + int err;
> >> +
> >> + err = platform_driver_register(&nct6694_hwmon_driver);
> >> + if (!err) {
> >> + if (err)
> > [Kalesh] This whole check looks strange. You can simplify this function as:
> > return platform_driver_register(&nct6694_hwmon_driver);
> >> + platform_driver_unregister(&nct6694_hwmon_driver);
> >> + }
> >> +
> >> + return err;
> >> +}
> >> +subsys_initcall(nct6694_init);
> >> +
> >> +static void __exit nct6694_exit(void)
> >> +{
> >> + platform_driver_unregister(&nct6694_hwmon_driver);
> >> +}
> >> +module_exit(nct6694_exit);
> >> +
> >> +MODULE_DESCRIPTION("USB-HWMON driver for NCT6694");
> >> +MODULE_AUTHOR("Ming Yu <tmyu0@...oton.com>");
> >> +MODULE_LICENSE("GPL");
> >> --
> >> 2.34.1
> >>
> >>
> >
> >
>
[Ming] For platform driver registration, I'll change it to
module_platform_driver() in the next patch.
Thank,
Ming
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