Re: [PATCH v2 2/2] hwmon: (sfctemp) Add StarFive JH7100 temperature sensor

From: Esmil
Date: Mon Jun 28 2021 - 11:33:17 EST


On Mon, 28 Jun 2021 at 17:08, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> On Thu, Jun 24, 2021 at 06:21:08PM +0200, Emil Renner Berthing wrote:
> > From: Emil Renner Berthing <kernel@xxxxxxxx>
> >
> > Register definitions and conversion constants based on sfctemp driver by
> > Samin in the StarFive 5.10 kernel.
> >
> > Signed-off-by: Emil Renner Berthing <kernel@xxxxxxxx>
> > Signed-off-by: Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
> > ---
> > Documentation/hwmon/index.rst | 1 +
> > Documentation/hwmon/sfctemp.rst | 32 ++++
> > MAINTAINERS | 8 +
> > drivers/hwmon/Kconfig | 10 ++
> > drivers/hwmon/Makefile | 1 +
> > drivers/hwmon/sfctemp.c | 288 ++++++++++++++++++++++++++++++++
> > 6 files changed, 340 insertions(+)
> > create mode 100644 Documentation/hwmon/sfctemp.rst
> > create mode 100644 drivers/hwmon/sfctemp.c
> >
> > diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> > index 9ed60fa84cbe..f23308e97d2e 100644
> > --- a/Documentation/hwmon/index.rst
> > +++ b/Documentation/hwmon/index.rst
> > @@ -161,6 +161,7 @@ Hardware Monitoring Kernel Drivers
> > sch5627
> > sch5636
> > scpi-hwmon
> > + sfctemp
> > sht15
> > sht21
> > sht3x
> > diff --git a/Documentation/hwmon/sfctemp.rst b/Documentation/hwmon/sfctemp.rst
> > new file mode 100644
> > index 000000000000..465edce2fea5
> > --- /dev/null
> > +++ b/Documentation/hwmon/sfctemp.rst
> > @@ -0,0 +1,32 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +
> > +Kernel driver sfctemp
> > +=====================
> > +
> > +Supported chips:
> > + - StarFive JH7100
> > +
> > +Authors:
> > + - Emil Renner Berthing <kernel@xxxxxxxx>
> > +
> > +Description
> > +-----------
> > +
> > +This driver adds support for reading the built-in temperature sensor on the
> > +JH7100 RISC-V SoC by StarFive Technology Co. Ltd.
> > +
> > +``sysfs`` interface
> > +-------------------
> > +
> > +The temperature sensor can be enabled, disabled and queried via the standard
> > +hwmon interface in sysfs under ``/sys/class/hwmon/hwmonX`` for some value of
> > +``X``:
> > +
> > +================ ==== =============================================
> > +Name Perm Description
> > +================ ==== =============================================
> > +temp1_enable RW Enable or disable temperature sensor.
> > + Automatically enabled by the driver,
> > + but may be disabled to save power.
> > +temp1_input RO Temperature reading in milli-degrees Celsius.
> > +================ ==== =============================================
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 8c5ee008301a..a7d25a672270 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -16535,6 +16535,14 @@ L: netdev@xxxxxxxxxxxxxxx
> > S: Supported
> > F: drivers/net/ethernet/sfc/
> >
> > +SFCTEMP HWMON DRIVER
> > +M: Emil Renner Berthing <kernel@xxxxxxxx>
> > +L: linux-hwmon@xxxxxxxxxxxxxxx
> > +S: Maintained
> > +F: Documentation/devicetree/bindings/hwmon/starfive,jh7100-temp.yaml
> > +F: Documentation/hwmon/sfctemp.rst
> > +F: drivers/hwmon/sfctemp.c
> > +
> > SFF/SFP/SFP+ MODULE SUPPORT
> > M: Russell King <linux@xxxxxxxxxxxxxxx>
> > L: netdev@xxxxxxxxxxxxxxx
> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > index 87624902ea80..7da8fd8beb06 100644
> > --- a/drivers/hwmon/Kconfig
> > +++ b/drivers/hwmon/Kconfig
> > @@ -1751,6 +1751,16 @@ 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"
> > + depends on OF && (RISCV || COMPILE_TEST)
> > + 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..4328aacf9272
> > --- /dev/null
> > +++ b/drivers/hwmon/sfctemp.c
> > @@ -0,0 +1,288 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2021 Emil Renner Berthing <kernel@xxxxxxxx>
> > + * Copyright (C) 2021 Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
> > + */
> > +#include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/hwmon.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +
> > +/*
> > + * TempSensor reset. The RSTN can be de-asserted once the analog core has
> > + * powered up. Trst(min 100ns)
> > + * 0:reset 1:de-assert
> > + */
> > +#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 conversion value output.
> > + * Temp(C)=DOUT*Y/4094 - K
> > + */
> > +#define SFCTEMP_DOUT_POS 16
> > +#define SFCTEMP_DOUT_MSK GENMASK(27, 16)
> > +
> > +/* DOUT to Celcius conversion constants */
> > +#define SFCTEMP_Y1000 237500L
> > +#define SFCTEMP_Z 4094L
> > +#define SFCTEMP_K1000 81100L
> > +
> > +struct sfctemp {
> > + /* serialize access to hardware register and enabled below */
> > + 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 void sfctemp_disable_action(void *data)
> > +{
> > + sfctemp_disable(data);
> > +}
> > +
> > +static int sfctemp_convert(struct sfctemp *sfctemp, long *val)
> > +{
> > + int ret;
> > +
> > + 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;
>
> Does this need to handle timeouts ?
>
> if (ret == 0)
> return -ETIMEDOUT;

Oh yes. Good catch. I thought it would automatically return -ETIMEDOUT
on timeout. I'll add that to the next version.

> > + 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;
> > + 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 = devm_add_action(dev, sfctemp_disable_action, sfctemp);
> > + if (ret)
> > + return ret;
> > +
> > + ret = sfctemp_enable(sfctemp);
> > + if (ret)
> > + return ret;
> > +
> > + hwmon_dev = devm_hwmon_device_register_with_info(dev, pdev->name, sfctemp,
> > + &sfctemp_chip_info, NULL);
> > + return PTR_ERR_OR_ZERO(hwmon_dev);
> > +}
> > +
> > +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,
> > +};
> > +module_platform_driver(sfctemp_driver);
> > +
> > +MODULE_AUTHOR("Emil Renner Berthing");
> > +MODULE_DESCRIPTION("StarFive JH7100 temperature sensor driver");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.32.0
> >