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Date: Thu, 17 Jun 2021 17:36:12 +0200
From: Emil Renner Berthing <kernel@...il.dk>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Jean Delvare <jdelvare@...e.com>, Rob Herring <robh+dt@...nel.org>,
Samin Guo <samin.guo@...rfivetech.com>,
linux-hwmon@...r.kernel.org, devicetree@...r.kernel.org,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 2/2] hwmon: (sfctemp) Add StarFive JH7100 temperature sensor
On Thu, 17 Jun 2021 at 17:07, Guenter Roeck <linux@...ck-us.net> wrote:
> On Wed, Jun 16, 2021 at 08:15:45PM +0200, Emil Renner Berthing wrote:
> > Register definitions based on sfctemp driver in the StarFive
> > 5.10 kernel by Samin Guo <samin.guo@...rfivetech.com>.
> >
> > Signed-off-by: Emil Renner Berthing <kernel@...il.dk>
> > ---
> >
> > @Samin: Only the register definitions and conversion constants are left
> > from your driver, but still it would be really nice if you could reply
> > to this mail with your Signed-off-by. Thanks!
> >
> >
> > drivers/hwmon/Kconfig | 9 ++
> > drivers/hwmon/Makefile | 1 +
> > drivers/hwmon/sfctemp.c | 309 ++++++++++++++++++++++++++++++++++++++++
>
> Documentation/hwmon/sfctemp is missing.
>
> > 3 files changed, 319 insertions(+)
> > create mode 100644 drivers/hwmon/sfctemp.c
> >
> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > index 87624902ea80..fa7562920dfa 100644
> > --- a/drivers/hwmon/Kconfig
> > +++ b/drivers/hwmon/Kconfig
> > @@ -1751,6 +1751,15 @@ config SENSORS_STTS751
> > This driver can also be built as a module. If so, the module
> > will be called stts751.
> >
> > +config SENSORS_SFCTEMP
> > + tristate "Starfive JH7100 temperature sensor"
> > + help
> > + If you say yes here you get support for temperature sensor
> > + on the Starfive JH7100 SoC.
> > +
> > + This driver can also be built as a module. If so, the module
> > + will be called sfctemp.
> > +
> > config SENSORS_SMM665
> > tristate "Summit Microelectronics SMM665"
> > depends on I2C
> > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> > index 59e78bc212cf..3723eb580bf3 100644
> > --- a/drivers/hwmon/Makefile
> > +++ b/drivers/hwmon/Makefile
> > @@ -167,6 +167,7 @@ obj-$(CONFIG_SENSORS_SBTSI) += sbtsi_temp.o
> > obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
> > obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o
> > obj-$(CONFIG_SENSORS_SCH5636) += sch5636.o
> > +obj-$(CONFIG_SENSORS_SFCTEMP) += sfctemp.o
> > obj-$(CONFIG_SENSORS_SL28CPLD) += sl28cpld-hwmon.o
> > obj-$(CONFIG_SENSORS_SHT15) += sht15.o
> > obj-$(CONFIG_SENSORS_SHT21) += sht21.o
> > diff --git a/drivers/hwmon/sfctemp.c b/drivers/hwmon/sfctemp.c
> > new file mode 100644
> > index 000000000000..62a838063e4e
> > --- /dev/null
> > +++ b/drivers/hwmon/sfctemp.c
> > @@ -0,0 +1,309 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2021 Emil Renner Berthing <kernel@...il.dk>
> > + * Copyright (C) 2021 Samin Guo <samin.guo@...rfivetech.com>
> > + */
> > +#include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/hwmon.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
>
> This may work on some systems, but on others it will result in:
>
> drivers/hwmon/sfctemp.c: In function ‘sfctemp_power_up’:
> drivers/hwmon/sfctemp.c:76:2: error: implicit declaration of function ‘writel’
>
> drivers/hwmon/sfctemp.c: In function ‘sfctemp_convert’:
> drivers/hwmon/sfctemp.c:144:17: error: implicit declaration of function ‘readl’
>
> It is necessary to include <linux/io.h>.
>
> > +
> > +/* TempSensor reset. The RSTN can be de-asserted once the analog core has
> > + * powered up. Trst(min 100ns)
> > + * 0:reset 1:de-assert */
>
> /*
> * Please use standard multi-line comments.
> * checkpatch would tell you, plus it has other complaints.
> * Please run checkpatch --strict and fix what it reports.
> */
> > +#define SFCTEMP_RSTN BIT(0)
> > +
> > +/* TempSensor analog core power down. The analog core will be powered up
> > + * Tpu(min 50us) after PD is de-asserted. RSTN should be held low until the
> > + * analog core is powered up.
> > + * 0:power up 1:power down */
> > +#define SFCTEMP_PD BIT(1)
> > +
> > +/* TempSensor start conversion enable.
> > + * 0:disable 1:enable */
> > +#define SFCTEMP_RUN BIT(2)
> > +
> > +/* TempSensor calibration mode enable.
> > + * 0:disable 1:enable */
> > +#define SFCTEMP_CAL BIT(4)
> > +
> > +/* TempSensor signature enable. Generate a toggle value outputting on DOUT for
> > + * test purpose.
> > + * 0:disable 1:enable */
> > +#define SFCTEMP_SGN BIT(5)
> > +
> > +/* TempSensor test access control.
> > + * 0000:normal 0001:Test1 0010:Test2 0011:Test3
> > + * 0100:Test4 1000:Test8 1001:Test9 */
> > +#define SFCTEMP_TM_Pos 12
> > +#define SFCTEMP_TM_Msk GENMASK(15, 12)
>
> Defines should upper case. Besides, the above defines are not
> used. Please remove unused defines, and please rename the others
> to be upper case only.
>
> > +
> > +/* TempSensor conversion value output.
> > + * Temp(c)=DOUT*Y/4094 - K */
> > +#define SFCTEMP_DOUT_Pos 16
> > +#define SFCTEMP_DOUT_Msk GENMASK(27, 16)
> > +
> > +/* TempSensor digital test output. */
> > +#define SFCTEMP_DIGO BIT(31)
> > +
> > +/* DOUT to Celcius conversion constants */
> > +#define SFCTEMP_Y1000 237500L
> > +#define SFCTEMP_Z 4094L
>
> Please use
>
> #define<space><definition><tab><value>, eg
>
> #define SFCTEMP_Y1000 237500L
> #define SFCTEMP_Z 4094L
>
> for all defines.
>
> > +#define SFCTEMP_K1000 81100L
> > +
> > +struct sfctemp {
> > + struct mutex lock;
> > + struct completion conversion_done;
> > + void __iomem *regs;
> > + bool enabled;
> > +};
> > +
> > +static irqreturn_t sfctemp_isr(int irq, void *data)
> > +{
> > + struct sfctemp *sfctemp = data;
> > +
> > + complete(&sfctemp->conversion_done);
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static void sfctemp_power_up(struct sfctemp *sfctemp)
> > +{
> > + /* make sure we're powered down first */
> > + writel(SFCTEMP_PD, sfctemp->regs);
> > + udelay(1);
> > +
> > + writel(0, sfctemp->regs);
> > + /* wait t_pu(50us) + t_rst(100ns) */
> > + usleep_range(60, 200);
> > +
> > + /* de-assert reset */
> > + writel(SFCTEMP_RSTN, sfctemp->regs);
> > + udelay(1); /* wait t_su(500ps) */
> > +}
> > +
> > +static void sfctemp_power_down(struct sfctemp *sfctemp)
> > +{
> > + writel(SFCTEMP_PD, sfctemp->regs);
> > +}
> > +
> > +static void sfctemp_run_single(struct sfctemp *sfctemp)
> > +{
> > + writel(SFCTEMP_RSTN | SFCTEMP_RUN, sfctemp->regs);
> > + udelay(1);
> > + writel(SFCTEMP_RSTN, sfctemp->regs);
> > +}
> > +
> > +static int sfctemp_enable(struct sfctemp *sfctemp)
> > +{
> > + mutex_lock(&sfctemp->lock);
> > + if (sfctemp->enabled)
> > + goto done;
> > +
> > + sfctemp_power_up(sfctemp);
> > + sfctemp->enabled = true;
> > +done:
> > + mutex_unlock(&sfctemp->lock);
> > + return 0;
> > +}
> > +
> > +static int sfctemp_disable(struct sfctemp *sfctemp)
> > +{
> > + mutex_lock(&sfctemp->lock);
> > + if (!sfctemp->enabled)
> > + goto done;
> > +
> > + sfctemp_power_down(sfctemp);
> > + sfctemp->enabled = false;
> > +done:
> > + mutex_unlock(&sfctemp->lock);
> > + return 0;
> > +}
> > +
> > +static int sfctemp_convert(struct sfctemp *sfctemp, long *val)
> > +{
> > + long ret;
>
> Why long ? Sure, wait_for_completion_interruptible_timeout()
> returns a long, but it will never return a value large enough to warrant
> a long here.
>
> > +
> > + mutex_lock(&sfctemp->lock);
> > + if (!sfctemp->enabled) {
> > + ret = -ENODATA;
> > + goto out;
> > + }
> > +
> > + sfctemp_run_single(sfctemp);
> > +
> > + ret = wait_for_completion_interruptible_timeout(&sfctemp->conversion_done,
> > + msecs_to_jiffies(10));
> > + if (ret < 0)
> > + goto out;
> > +
> > + /* calculate temperature in milli Celcius */
> > + *val = (long)((readl(sfctemp->regs) & SFCTEMP_DOUT_Msk) >> SFCTEMP_DOUT_Pos)
> > + * SFCTEMP_Y1000 / SFCTEMP_Z - SFCTEMP_K1000;
> > +
> > + ret = 0;
> > +out:
> > + mutex_unlock(&sfctemp->lock);
> > + return ret;
> > +}
> > +
> > +static umode_t sfctemp_is_visible(const void *data, enum hwmon_sensor_types type,
> > + u32 attr, int channel)
> > +{
> > + switch (type) {
> > + case hwmon_temp:
> > + switch (attr) {
> > + case hwmon_temp_enable:
> > + return 0644;
> > + case hwmon_temp_input:
> > + return 0444;
> > + }
> > + return 0;
> > + default:
> > + return 0;
> > + }
> > +}
> > +
> > +static int sfctemp_read(struct device *dev, enum hwmon_sensor_types type,
> > + u32 attr, int channel, long *val)
> > +{
> > + struct sfctemp *sfctemp = dev_get_drvdata(dev);
> > +
> > + switch (type) {
> > + case hwmon_temp:
> > + switch (attr) {
> > + case hwmon_temp_enable:
> > + *val = sfctemp->enabled;
> > + return 0;
> > + case hwmon_temp_input:
> > + return sfctemp_convert(sfctemp, val);
> > + }
> > + return -EINVAL;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +static int sfctemp_write(struct device *dev, enum hwmon_sensor_types type,
> > + u32 attr, int channel, long val)
> > +{
> > + struct sfctemp *sfctemp = dev_get_drvdata(dev);
> > +
> > + switch (type) {
> > + case hwmon_temp:
> > + switch (attr) {
> > + case hwmon_temp_enable:
> > + if (val == 0)
> > + return sfctemp_disable(sfctemp);
> > + if (val == 1)
> > + return sfctemp_enable(sfctemp);
> > + break;
> > + }
> > + return -EINVAL;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +static const struct hwmon_channel_info *sfctemp_info[] = {
> > + HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
> > + HWMON_CHANNEL_INFO(temp, HWMON_T_ENABLE | HWMON_T_INPUT),
> > + NULL
> > +};
> > +
> > +static const struct hwmon_ops sfctemp_hwmon_ops = {
> > + .is_visible = sfctemp_is_visible,
> > + .read = sfctemp_read,
> > + .write = sfctemp_write,
> > +};
> > +
> > +static const struct hwmon_chip_info sfctemp_chip_info = {
> > + .ops = &sfctemp_hwmon_ops,
> > + .info = sfctemp_info,
> > +};
> > +
> > +static int sfctemp_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct device *hwmon_dev;
> > + struct resource *mem;
> > + struct sfctemp *sfctemp;
> > + long val;
> > + int ret;
> > +
> > + sfctemp = devm_kzalloc(dev, sizeof(*sfctemp), GFP_KERNEL);
> > + if (!sfctemp)
> > + return -ENOMEM;
> > +
> > + dev_set_drvdata(dev, sfctemp);
> > + mutex_init(&sfctemp->lock);
> > + init_completion(&sfctemp->conversion_done);
> > +
> > + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + sfctemp->regs = devm_ioremap_resource(dev, mem);
> > + if (IS_ERR(sfctemp->regs))
> > + return PTR_ERR(sfctemp->regs);
> > +
> > + ret = platform_get_irq(pdev, 0);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = devm_request_irq(dev, ret, sfctemp_isr,
> > + IRQF_SHARED, pdev->name, sfctemp);
> > + if (ret) {
> > + dev_err(dev, "request irq failed: %d\n", ret);
> > + return ret;
> > + }
> > +
> > + ret = sfctemp_enable(sfctemp);
> > + if (ret)
> > + return ret;
>
> Please consider adding devm_add_action_or_reset() to disable the sensor.
> Then you can use devm_hwmon_device_register_with_info(), and there is
> no need for a remove function.
> > +
> > + hwmon_dev = hwmon_device_register_with_info(dev, pdev->name, sfctemp,
> > + &sfctemp_chip_info, NULL);
> > + if (IS_ERR(hwmon_dev))
> > + return PTR_ERR(hwmon_dev);
> > +
> > + /* do a conversion to check everything works */
> > + ret = sfctemp_convert(sfctemp, &val);
>
> Please drop this check; it will result in substantial boot delays.
> The assumption is the the hardware works; the system should not be
> optimized (slowed down) to handle a potential and hopefully rare
> failure case.
>
> > + if (ret) {
> > + hwmon_device_unregister(hwmon_dev);
> > + return ret;
> > + }
> > +
> > + dev_info(dev, "%ld.%03ld C\n", val / 1000, val % 1000);
>
> Please drop this message. Anyone interested in boot-time temperature
> readings can add a script and get it from sysfs attributes as needed.
>
> > + return 0;
> > +}
> > +
> > +static int sfctemp_remove(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct sfctemp *sfctemp = dev_get_drvdata(dev);
> > +
> > + hwmon_device_unregister(dev);
> > + return sfctemp_disable(sfctemp);
> > +}
> > +
> > +static const struct of_device_id sfctemp_of_match[] = {
> > + { .compatible = "starfive,jh7100-temp" },
> > + { /* sentinel */ }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, sfctemp_of_match);
> > +
> > +static struct platform_driver sfctemp_driver = {
> > + .driver = {
> > + .name = "sfctemp",
> > + .of_match_table = of_match_ptr(sfctemp_of_match),
> > + },
> > + .probe = sfctemp_probe,
> > + .remove = sfctemp_remove,
> > +};
> > +module_platform_driver(sfctemp_driver);
> > +
> > +MODULE_AUTHOR("Emil Renner Berthing");
> > +MODULE_DESCRIPTION("StarFive JH7100 temperature sensor driver");
> > +MODULE_LICENSE("GPL");
Hi Guenter,
Thanks for the review. It all sounds reasonable. I'll address it all in v2.
/Emil
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