hwmon: Add ST-Ericsson ABX500 hwmon driver

Each of ST-Ericsson X500 chip set series consists of both ABX500 and DBX500
chips. This is ABX500 hwmon driver, where the abx500.c is a common layer for
all ABX500s, and the ab8500.c is specific for AB8500 chip. Under this designed
structure, other chip specific files can be added simply using the same common
layer abx500.c.

Signed-off-by: Hongbo Zhang <hongbo.zhang@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>

1 files changed, 491 insertions, 0 deletions

diff --git a/drivers/hwmon/abx500.c b/drivers/hwmon/abx500.c
new file mode 100644
index 000000000000..b4ad87b31a37
--- /dev/null
+++ b/drivers/hwmon/abx500.c
@@ -0,0 +1,491 @@
+/*
+ * Copyright (C) ST-Ericsson 2010 - 2013
+ * Author: Martin Persson <martin.persson@stericsson.com>
+ *         Hongbo Zhang <hongbo.zhang@linaro.org>
+ * License Terms: GNU General Public License v2
+ *
+ * ABX500 does not provide auto ADC, so to monitor the required temperatures,
+ * a periodic work is used. It is more important to not wake up the CPU than
+ * to perform this job, hence the use of a deferred delay.
+ *
+ * A deferred delay for thermal monitor is considered safe because:
+ * If the chip gets too hot during a sleep state it's most likely due to
+ * external factors, such as the surrounding temperature. I.e. no SW decisions
+ * will make any difference.
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/workqueue.h>
+#include "abx500.h"
+
+#define DEFAULT_MONITOR_DELAY	HZ
+#define DEFAULT_MAX_TEMP	130
+
+static inline void schedule_monitor(struct abx500_temp *data)
+{
+	data->work_active = true;
+	schedule_delayed_work(&data->work, DEFAULT_MONITOR_DELAY);
+}
+
+static void threshold_updated(struct abx500_temp *data)
+{
+	int i;
+	for (i = 0; i < data->monitored_sensors; i++)
+		if (data->max[i] != 0 || data->min[i] != 0) {
+			schedule_monitor(data);
+			return;
+		}
+
+	dev_dbg(&data->pdev->dev, "No active thresholds.\n");
+	cancel_delayed_work_sync(&data->work);
+	data->work_active = false;
+}
+
+static void gpadc_monitor(struct work_struct *work)
+{
+	int temp, i, ret;
+	char alarm_node[30];
+	bool updated_min_alarm, updated_max_alarm;
+	struct abx500_temp *data;
+
+	data = container_of(work, struct abx500_temp, work.work);
+	mutex_lock(&data->lock);
+
+	for (i = 0; i < data->monitored_sensors; i++) {
+		/* Thresholds are considered inactive if set to 0 */
+		if (data->max[i] == 0 && data->min[i] == 0)
+			continue;
+
+		if (data->max[i] < data->min[i])
+			continue;
+
+		ret = data->ops.read_sensor(data, data->gpadc_addr[i], &temp);
+		if (ret < 0) {
+			dev_err(&data->pdev->dev, "GPADC read failed\n");
+			continue;
+		}
+
+		updated_min_alarm = false;
+		updated_max_alarm = false;
+
+		if (data->min[i] != 0) {
+			if (temp < data->min[i]) {
+				if (data->min_alarm[i] == false) {
+					data->min_alarm[i] = true;
+					updated_min_alarm = true;
+				}
+			} else {
+				if (data->min_alarm[i] == true) {
+					data->min_alarm[i] = false;
+					updated_min_alarm = true;
+				}
+			}
+		}
+		if (data->max[i] != 0) {
+			if (temp > data->max[i]) {
+				if (data->max_alarm[i] == false) {
+					data->max_alarm[i] = true;
+					updated_max_alarm = true;
+				}
+			} else if (temp < data->max[i] - data->max_hyst[i]) {
+				if (data->max_alarm[i] == true) {
+					data->max_alarm[i] = false;
+					updated_max_alarm = true;
+				}
+			}
+		}
+
+		if (updated_min_alarm) {
+			ret = sprintf(alarm_node, "temp%d_min_alarm", i + 1);
+			sysfs_notify(&data->pdev->dev.kobj, NULL, alarm_node);
+		}
+		if (updated_max_alarm) {
+			ret = sprintf(alarm_node, "temp%d_max_alarm", i + 1);
+			sysfs_notify(&data->pdev->dev.kobj, NULL, alarm_node);
+		}
+	}
+
+	schedule_monitor(data);
+	mutex_unlock(&data->lock);
+}
+
+/* HWMON sysfs interfaces */
+static ssize_t show_name(struct device *dev, struct device_attribute *devattr,
+			 char *buf)
+{
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	/* Show chip name */
+	return data->ops.show_name(dev, devattr, buf);
+}
+
+static ssize_t show_label(struct device *dev,
+			  struct device_attribute *devattr, char *buf)
+{
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	/* Show each sensor label */
+	return data->ops.show_label(dev, devattr, buf);
+}
+
+static ssize_t show_input(struct device *dev,
+			  struct device_attribute *devattr, char *buf)
+{
+	int ret, temp;
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	u8 gpadc_addr = data->gpadc_addr[attr->index];
+
+	ret = data->ops.read_sensor(data, gpadc_addr, &temp);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", temp);
+}
+
+/* Set functions (RW nodes) */
+static ssize_t set_min(struct device *dev, struct device_attribute *devattr,
+		       const char *buf, size_t count)
+{
+	unsigned long val;
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	int res = kstrtol(buf, 10, &val);
+	if (res < 0)
+		return res;
+
+	val = clamp_val(val, 0, DEFAULT_MAX_TEMP);
+
+	mutex_lock(&data->lock);
+	data->min[attr->index] = val;
+	threshold_updated(data);
+	mutex_unlock(&data->lock);
+
+	return count;
+}
+
+static ssize_t set_max(struct device *dev, struct device_attribute *devattr,
+		       const char *buf, size_t count)
+{
+	unsigned long val;
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	int res = kstrtol(buf, 10, &val);
+	if (res < 0)
+		return res;
+
+	val = clamp_val(val, 0, DEFAULT_MAX_TEMP);
+
+	mutex_lock(&data->lock);
+	data->max[attr->index] = val;
+	threshold_updated(data);
+	mutex_unlock(&data->lock);
+
+	return count;
+}
+
+static ssize_t set_max_hyst(struct device *dev,
+			    struct device_attribute *devattr,
+			    const char *buf, size_t count)
+{
+	unsigned long val;
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	int res = kstrtoul(buf, 10, &val);
+	if (res < 0)
+		return res;
+
+	val = clamp_val(val, 0, DEFAULT_MAX_TEMP);
+
+	mutex_lock(&data->lock);
+	data->max_hyst[attr->index] = val;
+	threshold_updated(data);
+	mutex_unlock(&data->lock);
+
+	return count;
+}
+
+/* Show functions (RO nodes) */
+static ssize_t show_min(struct device *dev,
+			struct device_attribute *devattr, char *buf)
+{
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+
+	return sprintf(buf, "%ld\n", data->min[attr->index]);
+}
+
+static ssize_t show_max(struct device *dev,
+			struct device_attribute *devattr, char *buf)
+{
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+
+	return sprintf(buf, "%ld\n", data->max[attr->index]);
+}
+
+static ssize_t show_max_hyst(struct device *dev,
+			     struct device_attribute *devattr, char *buf)
+{
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+
+	return sprintf(buf, "%ld\n", data->max_hyst[attr->index]);
+}
+
+static ssize_t show_min_alarm(struct device *dev,
+			      struct device_attribute *devattr, char *buf)
+{
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+
+	return sprintf(buf, "%d\n", data->min_alarm[attr->index]);
+}
+
+static ssize_t show_max_alarm(struct device *dev,
+			      struct device_attribute *devattr, char *buf)
+{
+	struct abx500_temp *data = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+
+	return sprintf(buf, "%d\n", data->max_alarm[attr->index]);
+}
+
+static mode_t abx500_attrs_visible(struct kobject *kobj,
+				   struct attribute *attr, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct abx500_temp *data = dev_get_drvdata(dev);
+
+	if (data->ops.is_visible)
+		return data->ops.is_visible(attr, n);
+
+	return attr->mode;
+}
+
+/* Chip name, required by hwmon */
+static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, 0);
+
+/* GPADC - SENSOR1 */
+static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_label, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_min, set_min, 0);
+static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_max, set_max, 0);
+static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
+			  show_max_hyst, set_max_hyst, 0);
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_min_alarm, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_max_alarm, NULL, 0);
+
+/* GPADC - SENSOR2 */
+static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, show_label, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_min, set_min, 1);
+static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_max, set_max, 1);
+static SENSOR_DEVICE_ATTR(temp2_max_hyst, S_IWUSR | S_IRUGO,
+			  show_max_hyst, set_max_hyst, 1);
+static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_min_alarm, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_max_alarm, NULL, 1);
+
+/* GPADC - SENSOR3 */
+static SENSOR_DEVICE_ATTR(temp3_label, S_IRUGO, show_label, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_input, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp3_min, S_IWUSR | S_IRUGO, show_min, set_min, 2);
+static SENSOR_DEVICE_ATTR(temp3_max, S_IWUSR | S_IRUGO, show_max, set_max, 2);
+static SENSOR_DEVICE_ATTR(temp3_max_hyst, S_IWUSR | S_IRUGO,
+			  show_max_hyst, set_max_hyst, 2);
+static SENSOR_DEVICE_ATTR(temp3_min_alarm, S_IRUGO, show_min_alarm, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_max_alarm, NULL, 2);
+
+/* GPADC - SENSOR4 */
+static SENSOR_DEVICE_ATTR(temp4_label, S_IRUGO, show_label, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_input, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp4_min, S_IWUSR | S_IRUGO, show_min, set_min, 3);
+static SENSOR_DEVICE_ATTR(temp4_max, S_IWUSR | S_IRUGO, show_max, set_max, 3);
+static SENSOR_DEVICE_ATTR(temp4_max_hyst, S_IWUSR | S_IRUGO,
+			  show_max_hyst, set_max_hyst, 3);
+static SENSOR_DEVICE_ATTR(temp4_min_alarm, S_IRUGO, show_min_alarm, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_max_alarm, NULL, 3);
+
+struct attribute *abx500_temp_attributes[] = {
+	&sensor_dev_attr_name.dev_attr.attr,
+
+	&sensor_dev_attr_temp1_label.dev_attr.attr,
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_min.dev_attr.attr,
+	&sensor_dev_attr_temp1_max.dev_attr.attr,
+	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
+	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+
+	&sensor_dev_attr_temp2_label.dev_attr.attr,
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_temp2_min.dev_attr.attr,
+	&sensor_dev_attr_temp2_max.dev_attr.attr,
+	&sensor_dev_attr_temp2_max_hyst.dev_attr.attr,
+	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
+
+	&sensor_dev_attr_temp3_label.dev_attr.attr,
+	&sensor_dev_attr_temp3_input.dev_attr.attr,
+	&sensor_dev_attr_temp3_min.dev_attr.attr,
+	&sensor_dev_attr_temp3_max.dev_attr.attr,
+	&sensor_dev_attr_temp3_max_hyst.dev_attr.attr,
+	&sensor_dev_attr_temp3_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
+
+	&sensor_dev_attr_temp4_label.dev_attr.attr,
+	&sensor_dev_attr_temp4_input.dev_attr.attr,
+	&sensor_dev_attr_temp4_min.dev_attr.attr,
+	&sensor_dev_attr_temp4_max.dev_attr.attr,
+	&sensor_dev_attr_temp4_max_hyst.dev_attr.attr,
+	&sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group abx500_temp_group = {
+	.attrs = abx500_temp_attributes,
+	.is_visible = abx500_attrs_visible,
+};
+
+static irqreturn_t abx500_temp_irq_handler(int irq, void *irq_data)
+{
+	struct platform_device *pdev = irq_data;
+	struct abx500_temp *data = platform_get_drvdata(pdev);
+
+	data->ops.irq_handler(irq, data);
+	return IRQ_HANDLED;
+}
+
+static int setup_irqs(struct platform_device *pdev)
+{
+	int ret;
+	int irq = platform_get_irq_byname(pdev, "ABX500_TEMP_WARM");
+
+	if (irq < 0) {
+		dev_err(&pdev->dev, "Get irq by name failed\n");
+		return irq;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+		abx500_temp_irq_handler, IRQF_NO_SUSPEND, "abx500-temp", pdev);
+	if (ret < 0)
+		dev_err(&pdev->dev, "Request threaded irq failed (%d)\n", ret);
+
+	return ret;
+}
+
+static int abx500_temp_probe(struct platform_device *pdev)
+{
+	struct abx500_temp *data;
+	int err;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->pdev = pdev;
+	mutex_init(&data->lock);
+
+	/* Chip specific initialization */
+	err = abx500_hwmon_init(data);
+	if (err	< 0 || !data->ops.read_sensor || !data->ops.show_name ||
+			!data->ops.show_label)
+		return err;
+
+	INIT_DEFERRABLE_WORK(&data->work, gpadc_monitor);
+
+	platform_set_drvdata(pdev, data);
+
+	err = sysfs_create_group(&pdev->dev.kobj, &abx500_temp_group);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Create sysfs group failed (%d)\n", err);
+		return err;
+	}
+
+	data->hwmon_dev = hwmon_device_register(&pdev->dev);
+	if (IS_ERR(data->hwmon_dev)) {
+		err = PTR_ERR(data->hwmon_dev);
+		dev_err(&pdev->dev, "Class registration failed (%d)\n", err);
+		goto exit_sysfs_group;
+	}
+
+	if (data->ops.irq_handler) {
+		err = setup_irqs(pdev);
+		if (err < 0)
+			goto exit_hwmon_reg;
+	}
+	return 0;
+
+exit_hwmon_reg:
+	hwmon_device_unregister(data->hwmon_dev);
+exit_sysfs_group:
+	sysfs_remove_group(&pdev->dev.kobj, &abx500_temp_group);
+	return err;
+}
+
+static int abx500_temp_remove(struct platform_device *pdev)
+{
+	struct abx500_temp *data = platform_get_drvdata(pdev);
+
+	cancel_delayed_work_sync(&data->work);
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&pdev->dev.kobj, &abx500_temp_group);
+
+	return 0;
+}
+
+static int abx500_temp_suspend(struct platform_device *pdev,
+			       pm_message_t state)
+{
+	struct abx500_temp *data = platform_get_drvdata(pdev);
+
+	if (data->work_active)
+		cancel_delayed_work_sync(&data->work);
+
+	return 0;
+}
+
+static int abx500_temp_resume(struct platform_device *pdev)
+{
+	struct abx500_temp *data = platform_get_drvdata(pdev);
+
+	if (data->work_active)
+		schedule_monitor(data);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id abx500_temp_match[] = {
+	{ .compatible = "stericsson,abx500-temp" },
+	{},
+};
+#endif
+
+static struct platform_driver abx500_temp_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "abx500-temp",
+		.of_match_table = of_match_ptr(abx500_temp_match),
+	},
+	.suspend = abx500_temp_suspend,
+	.resume = abx500_temp_resume,
+	.probe = abx500_temp_probe,
+	.remove = abx500_temp_remove,
+};
+
+module_platform_driver(abx500_temp_driver);
+
+MODULE_AUTHOR("Martin Persson <martin.persson@stericsson.com>");
+MODULE_DESCRIPTION("ABX500 temperature driver");
+MODULE_LICENSE("GPL");