On Thu, 17 Jun 2021 at 17:07, Guenter Roeck [off-list ref] wrote:

On Wed, Jun 16, 2021 at 08:15:45PM +0200, Emil Renner Berthing wrote:

quoted

Register definitions based on sfctemp driver in the StarFive
5.10 kernel by Samin Guo [off-list ref].

Signed-off-by: Emil Renner Berthing <kernel@esmil.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.

quoted

 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@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/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>.

quoted

+
+/* 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.
 */

quoted

+#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.

quoted

+
+/* 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.

quoted

+#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.

quoted

+
+     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.

quoted

+
+     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.

quoted

+     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.

quoted

+     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