From: Moritz Fischer <mdf@xxxxxxxxxx>
This adds a hwmon driver for the Chromium EC's fans
and temperature sensors.
Signed-off-by: Moritz Fischer <mdf@xxxxxxxxxx>
---
This one still needs some work, but I figured some early feedback might not hurt.
Specifically I was wondering if using the devm_hwmon_register_with_info() is
preferable to the devm_hwmon_register_with_groups().
The EC has a bunch of additional features such as setting thermal limits etc,
which I'd still like to add but I figured I'll get some feedback on what I got so far.
Thanks,
Moritz
---
drivers/hwmon/Kconfig | 8 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/cros-ec-hwmon.c | 244 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 253 insertions(+)
create mode 100644 drivers/hwmon/cros-ec-hwmon.c
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 0649d53f3..3b9155f 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1254,6 +1254,14 @@ config SENSORS_PCF8591
These devices are hard to detect and rarely found on mainstream
hardware. If unsure, say N.
+config SENSORS_CROS_EC
+ tristate "ChromeOS EC hwmon"
+ depends on MFD_CROS_EC
+ help
+ If you say yes here you get hwmon support that will expose the
+ ChromeOS internal sensors for fanspeed and temperature to the
+ Linux hwmon subsystem.
+
source drivers/hwmon/pmbus/Kconfig
config SENSORS_PWM_FAN
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 5509edf..e59b5da 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -134,6 +134,7 @@ obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
obj-$(CONFIG_SENSORS_PC87427) += pc87427.o
obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o
obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o
+obj-$(CONFIG_SENSORS_CROS_EC) += cros-ec-hwmon.o
obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o
obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o
obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
diff --git a/drivers/hwmon/cros-ec-hwmon.c b/drivers/hwmon/cros-ec-hwmon.c
new file mode 100644
index 0000000..29d8b06
--- /dev/null
+++ b/drivers/hwmon/cros-ec-hwmon.c
@@ -0,0 +1,244 @@
+/*
+ * Copyright (c) 2017, National Instruments Corp.
+ *
+ * Chromium EC Fan speed and temperature sensor driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/of_platform.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/bitops.h>
+#include <linux/mfd/cros_ec.h>
+
+struct cros_ec_hwmon_priv {
+ struct cros_ec_device *ec;
+ struct device *hwmon_dev;
+
+ struct attribute **attrs;
+
+ struct attribute_group attr_group;
+ const struct attribute_group *groups[2];
+};
+
+#define KELVIN_TO_MILLICELSIUS(x) (((x) - 273) * 1000)
+
+static int __cros_ec_hwmon_probe_fans(struct cros_ec_hwmon_priv *priv)
+{
+ int err, idx;
+ uint16_t data;
+
+ for (idx = 0; idx < EC_FAN_SPEED_ENTRIES; idx++) {
+ err = cros_ec_read_mapped_mem16(priv->ec,
+ EC_MEMMAP_FAN + 2 * idx,
+ &data);
+ if (err)
+ return err;
+
+ if (data == EC_FAN_SPEED_NOT_PRESENT)
+ break;
+ }
+
+ return idx;
+}
+
+static int __cros_ec_hwmon_probe_temps(struct cros_ec_hwmon_priv *priv)
+{
+ uint8_t data;
+ int err, idx;
+
+ err = cros_ec_read_mapped_mem8(priv->ec, EC_MEMMAP_THERMAL_VERSION,
+ &data);
+
+ /* if we have a read error, or EC_MEMMAP_THERMAL_VERSION is not set,
+ * most likely we don't have temperature sensors ...
+ */
+ if (err || !data)
+ return 0;
+
+ for (idx = 0; idx < EC_TEMP_SENSOR_ENTRIES; idx++) {
+ err = cros_ec_read_mapped_mem8(priv->ec,
+ EC_MEMMAP_TEMP_SENSOR + idx,
+ &data);
+ if (err)
+ return idx;
+
+ /* this assumes that they're all good up to idx */
+ switch (data) {
+ case EC_TEMP_SENSOR_NOT_PRESENT:
+ case EC_TEMP_SENSOR_ERROR:
+ case EC_TEMP_SENSOR_NOT_POWERED:
+ case EC_TEMP_SENSOR_NOT_CALIBRATED:
+ return idx;
+ default:
+ continue;
+ };
+ }
+
+ return idx;
+}
+
+static ssize_t cros_ec_hwmon_read_fan_rpm(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ uint16_t data;
+ int err;
+ struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
+ struct cros_ec_hwmon_priv *priv = dev_get_drvdata(dev);
+
+ err = cros_ec_read_mapped_mem16(priv->ec,
+ EC_MEMMAP_FAN + 2 * sattr->index,
+ &data);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%d\n", data);
+}
+
+static ssize_t cros_ec_hwmon_read_temp(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ uint8_t data;
+ int err, tmp;
+
+ struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
+ struct cros_ec_hwmon_priv *priv = dev_get_drvdata(dev);
+
+ err = cros_ec_read_mapped_mem8(priv->ec,
+ EC_MEMMAP_TEMP_SENSOR + 1 * sattr->index,
+ &data);
+ if (err)
+ return err;
+
+ switch (data) {
+ case EC_TEMP_SENSOR_NOT_PRESENT:
+ case EC_TEMP_SENSOR_ERROR:
+ case EC_TEMP_SENSOR_NOT_POWERED:
+ case EC_TEMP_SENSOR_NOT_CALIBRATED:
+ dev_info(priv->ec->dev, "Failure: result=%d\n", data);
+ return -EIO;
+ }
+
+ /* make sure we don't overflow when adding offset*/
+ tmp = data + EC_TEMP_SENSOR_OFFSET;
+
+ return sprintf(buf, "%d\n", KELVIN_TO_MILLICELSIUS(tmp));
+}
+
+static int cros_ec_hwmon_probe(struct platform_device *pdev)
+{
+ struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
+ struct cros_ec_hwmon_priv *ec_hwmon;
+ struct sensor_device_attribute *attr;
+ int num_fans, num_temps, i;
+
+ ec_hwmon = devm_kzalloc(&pdev->dev, sizeof(*ec_hwmon), GFP_KERNEL);
+ if (!ec_hwmon)
+ return -ENOMEM;
+ ec_hwmon->ec = ec;
+
+ num_fans = __cros_ec_hwmon_probe_fans(ec_hwmon);
+ if (num_fans < 0)
+ return num_fans;
+
+ num_temps = __cros_ec_hwmon_probe_temps(ec_hwmon);
+ if (num_fans < 0)
+ return num_temps;
+
+ ec_hwmon->attrs = devm_kzalloc(&pdev->dev,
+ sizeof(*ec_hwmon->attrs) *
+ (num_fans + num_temps + 1),
+ GFP_KERNEL);
+ if (!ec_hwmon->attrs)
+ return -ENOMEM;
+
+ for (i = 0; i < num_fans; i++) {
+ attr = devm_kzalloc(&pdev->dev, sizeof(*attr), GFP_KERNEL);
+ if (!attr)
+ return -ENOMEM;
+ sysfs_attr_init(&attr->dev_attr.attr);
+ attr->dev_attr.attr.name = devm_kasprintf(&pdev->dev,
+ GFP_KERNEL,
+ "fan%d_input",
+ i);
+ if (!attr->dev_attr.attr.name)
+ return -ENOMEM;
+
+ attr->dev_attr.show = cros_ec_hwmon_read_fan_rpm;
+ attr->dev_attr.attr.mode = S_IRUGO;
+ attr->index = i;
+ ec_hwmon->attrs[i] = &attr->dev_attr.attr;
+
+ }
+
+ for (i = 0; i < num_temps; i++) {
+ attr = devm_kzalloc(&pdev->dev, sizeof(*attr), GFP_KERNEL);
+ if (!attr)
+ return -ENOMEM;
+ sysfs_attr_init(&attr->dev_attr.attr);
+ attr->dev_attr.attr.name = devm_kasprintf(&pdev->dev,
+ GFP_KERNEL,
+ "temp%d_input",
+ i);
+ if (!attr->dev_attr.attr.name)
+ return -ENOMEM;
+
+ attr->dev_attr.show = cros_ec_hwmon_read_temp;
+ attr->dev_attr.attr.mode = S_IRUGO;
+ attr->index = i;
+ ec_hwmon->attrs[i + num_fans] = &attr->dev_attr.attr;
+
+ }
+
+ ec_hwmon->attr_group.attrs = ec_hwmon->attrs;
+ ec_hwmon->groups[0] = &ec_hwmon->attr_group;
+
+ ec_hwmon->hwmon_dev = devm_hwmon_device_register_with_groups(&pdev->dev,
+ "ec_hwmon", ec_hwmon, ec_hwmon->groups);
+
+ if (IS_ERR(ec_hwmon->hwmon_dev))
+ return PTR_ERR(ec_hwmon->hwmon_dev);
+
+ platform_set_drvdata(pdev, ec_hwmon);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id cros_ec_hwmon_of_match[] = {
+ { .compatible = "google,cros-ec-hwmon" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, cros_ec_hwmon_of_match);
+#endif
+
+static struct platform_driver cros_ec_hwmon_driver = {
+ .probe = cros_ec_hwmon_probe,
+ .driver = {
+ .name = "cros-ec-hwmon",
+ .of_match_table = of_match_ptr(cros_ec_hwmon_of_match),
+ },
+};
+module_platform_driver(cros_ec_hwmon_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ChromeOS EC Hardware Monitor driver");
+MODULE_ALIAS("platform:cros-ec-hwmon");
+MODULE_AUTHOR("Moritz Fischer <mdf@xxxxxxxxxx>");
--
2.7.4
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