On Mon, 28 Jun 2021 at 17:08, Guenter Roeck [off-list ref] wrote:

On Thu, Jun 24, 2021 at 06:21:08PM +0200, Emil Renner Berthing wrote:

quoted

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 <redacted>
---
 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;

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

quoted

+     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