hwmon: sy7636a: Add temperature driver for sy7636a

This is a multi-function device to interface with the sy7636a
EPD PMIC chip from Silergy.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index df20022..6e0906e 100644 (file)
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -185,6 +185,7 @@ Hardware Monitoring Kernel Drivers
    smsc47m1
    sparx5-temp
    stpddc60
+   sy7636a-hwmon
    tc654
    tc74
    thmc50

diff --git a/Documentation/hwmon/sy7636a-hwmon.rst b/Documentation/hwmon/sy7636a-hwmon.rst
new file mode 100644 (file)
index 0000000..5612079
--- /dev/null
+++ b/Documentation/hwmon/sy7636a-hwmon.rst
@@ -0,0 +1,26 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver sy7636a-hwmon
+=========================
+
+Supported chips:
+
+ * Silergy SY7636A PMIC
+
+
+Description
+-----------
+
+This driver adds hardware temperature reading support for
+the Silergy SY7636A PMIC.
+
+The following sensors are supported
+
+  * Temperature
+      - SoC on-die temperature in milli-degree C
+
+sysfs-Interface
+---------------
+
+temp0_input
+       - SoC on-die temperature (milli-degree C)

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 8df25f1..aa5785e 100644 (file)
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1672,6 +1672,15 @@ config SENSORS_SIS5595
          This driver can also be built as a module. If so, the module
          will be called sis5595.
 
+config SENSORS_SY7636A
+       tristate "Silergy SY7636A"
+       help
+         If you say yes here you get support for the thermistor readout of
+         the Silergy SY7636A PMIC.
+
+         This driver can also be built as a module.  If so, the module
+         will be called sy7636a-hwmon.
+
 config SENSORS_DME1737
        tristate "SMSC DME1737, SCH311x and compatibles"
        depends on I2C && !PPC

diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 185f946..fe54a3d 100644 (file)
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -186,6 +186,7 @@ obj-$(CONFIG_SENSORS_SMSC47M1)      += smsc47m1.o
 obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
 obj-$(CONFIG_SENSORS_SPARX5)   += sparx5-temp.o
 obj-$(CONFIG_SENSORS_STTS751)  += stts751.o
+obj-$(CONFIG_SENSORS_SY7636A)  += sy7636a-hwmon.o
 obj-$(CONFIG_SENSORS_AMC6821)  += amc6821.o
 obj-$(CONFIG_SENSORS_TC74)     += tc74.o
 obj-$(CONFIG_SENSORS_THMC50)   += thmc50.o

diff --git a/drivers/hwmon/sy7636a-hwmon.c b/drivers/hwmon/sy7636a-hwmon.c
new file mode 100644 (file)
index 0000000..6dd9c2a
--- /dev/null
+++ b/drivers/hwmon/sy7636a-hwmon.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Functions to access SY3686A power management chip temperature
+ *
+ * Copyright (C) 2021 reMarkable AS - http://www.remarkable.com/
+ *
+ * Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>
+ *          Alistair Francis <alistair@alistair23.me>
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/machine.h>
+
+#include <linux/mfd/sy7636a.h>
+
+static int sy7636a_read(struct device *dev, enum hwmon_sensor_types type,
+                       u32 attr, int channel, long *temp)
+{
+       struct regmap *regmap = dev_get_drvdata(dev);
+       int ret, reg_val;
+
+       ret = regmap_read(regmap,
+                         SY7636A_REG_TERMISTOR_READOUT, &reg_val);
+       if (ret)
+               return ret;
+
+       *temp = reg_val * 1000;
+
+       return 0;
+}
+
+static umode_t sy7636a_is_visible(const void *data,
+                                 enum hwmon_sensor_types type,
+                                 u32 attr, int channel)
+{
+       if (type != hwmon_temp)
+               return 0;
+
+       if (attr != hwmon_temp_input)
+               return 0;
+
+       return 0444;
+}
+
+static const struct hwmon_ops sy7636a_hwmon_ops = {
+       .is_visible = sy7636a_is_visible,
+       .read = sy7636a_read,
+};
+
+static const struct hwmon_channel_info *sy7636a_info[] = {
+       HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
+       HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+       NULL
+};
+
+static const struct hwmon_chip_info sy7636a_chip_info = {
+       .ops = &sy7636a_hwmon_ops,
+       .info = sy7636a_info,
+};
+
+static int sy7636a_sensor_probe(struct platform_device *pdev)
+{
+       struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
+       struct regulator *regulator;
+       struct device *hwmon_dev;
+       int err;
+
+       if (!regmap)
+               return -EPROBE_DEFER;
+
+       regulator = devm_regulator_get(&pdev->dev, "vcom");
+       if (IS_ERR(regulator))
+               return PTR_ERR(regulator);
+
+       err = regulator_enable(regulator);
+       if (err)
+               return err;
+
+       hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
+                                                        "sy7636a_temperature", regmap,
+                                                        &sy7636a_chip_info, NULL);
+
+       if (IS_ERR(hwmon_dev)) {
+               err = PTR_ERR(hwmon_dev);
+               dev_err(&pdev->dev, "Unable to register hwmon device, returned %d\n", err);
+               return err;
+       }
+
+       return 0;
+}
+
+static struct platform_driver sy7636a_sensor_driver = {
+       .probe = sy7636a_sensor_probe,
+       .driver = {
+               .name = "sy7636a-temperature",
+       },
+};
+module_platform_driver(sy7636a_sensor_driver);
+
+MODULE_DESCRIPTION("SY7636A sensor driver");
+MODULE_LICENSE("GPL");