[PATCH v3 2/2] hwmon: (sfctemp) Add StarFive JH7100 temperature sensor

Emil Renner Berthing
2021-07-26T17:28:05Z

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 | 291 ++++++++++++++++++++++++++++++++
6 files changed, 343 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 bc01601ea81a..961b6d93bead 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -164,6 +164,7 @@ 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 19135a9d778e..6fb1fd015c19 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16751,6 +16751,14 @@ 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 e3675377bc5d..ef3e345d6ce3 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1762,6 +1762,16 @@ 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 d712c61c1f5e..869f8806561e 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..35d3ca682e50
--- /dev/null
+++ b/drivers/hwmon/sfctemp.c
@@ -0,0 +1,291 @@
+// 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) {
+ if (ret == 0)
+ ret = -ETIMEDOUT;
+ 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;
+ 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