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SubjectRe: [PATCH v2 2/2] hwmon: (sfctemp) Add StarFive JH7100 temperature sensor
On Thu, Jun 24, 2021 at 06:21:08PM +0200, Emil Renner Berthing wrote:
> From: Emil Renner Berthing <kernel@esmil.dk>
>
> Register definitions and conversion constants based on sfctemp driver by
> Samin in the StarFive 5.10 kernel.
>
> Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
> Signed-off-by: Samin Guo <samin.guo@starfivetech.com>
> ---
> 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@esmil.dk>
> +
> +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@vger.kernel.org
> S: Supported
> F: drivers/net/ethernet/sfc/
>
> +SFCTEMP HWMON DRIVER
> +M: Emil Renner Berthing <kernel@esmil.dk>
> +L: linux-hwmon@vger.kernel.org
> +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@armlinux.org.uk>
> L: netdev@vger.kernel.org
> 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@esmil.dk>
> + * Copyright (C) 2021 Samin Guo <samin.guo@starfivetech.com>
> + */
> +#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;
> +
> + /* 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;
> + 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
>

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