thermal: qcom: tsens: Add a skeletal TSENS drivers

TSENS is Qualcomms' thermal temperature sensor device. It
supports reading temperatures from multiple thermal sensors
present on various QCOM SoCs.
Calibration data is generally read from a non-volatile memory
(eeprom) device.

Add a skeleton driver with all the necessary abstractions so
a variety of qcom device families which support TSENS can
add driver extensions.

Also add the required device tree bindings which can be used
to describe the TSENS device in DT.

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

1 files changed, 195 insertions, 0 deletions

diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c
new file mode 100644
index 000000000000..17d7b5538f3a
--- /dev/null
+++ b/drivers/thermal/qcom/tsens.c
@@ -0,0 +1,195 @@
+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include "tsens.h"
+
+static int tsens_get_temp(void *data, int *temp)
+{
+	const struct tsens_sensor *s = data;
+	struct tsens_device *tmdev = s->tmdev;
+
+	return tmdev->ops->get_temp(tmdev, s->id, temp);
+}
+
+static int tsens_get_trend(void *data, long *temp)
+{
+	const struct tsens_sensor *s = data;
+	struct tsens_device *tmdev = s->tmdev;
+
+	if (tmdev->ops->get_trend)
+		return tmdev->ops->get_trend(tmdev, s->id, temp);
+
+	return -ENOTSUPP;
+}
+
+static int tsens_suspend(struct device *dev)
+{
+	struct tsens_device *tmdev = dev_get_drvdata(dev);
+
+	if (tmdev->ops && tmdev->ops->suspend)
+		return tmdev->ops->suspend(tmdev);
+
+	return 0;
+}
+
+static int tsens_resume(struct device *dev)
+{
+	struct tsens_device *tmdev = dev_get_drvdata(dev);
+
+	if (tmdev->ops && tmdev->ops->resume)
+		return tmdev->ops->resume(tmdev);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(tsens_pm_ops, tsens_suspend, tsens_resume);
+
+static const struct of_device_id tsens_table[] = {
+	{
+		.compatible = "qcom,msm8916-tsens",
+	}, {
+		.compatible = "qcom,msm8974-tsens",
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, tsens_table);
+
+static const struct thermal_zone_of_device_ops tsens_of_ops = {
+	.get_temp = tsens_get_temp,
+	.get_trend = tsens_get_trend,
+};
+
+static int tsens_register(struct tsens_device *tmdev)
+{
+	int i;
+	struct thermal_zone_device *tzd;
+	u32 *hw_id, n = tmdev->num_sensors;
+
+	hw_id = devm_kcalloc(tmdev->dev, n, sizeof(u32), GFP_KERNEL);
+	if (!hw_id)
+		return -ENOMEM;
+
+	for (i = 0;  i < tmdev->num_sensors; i++) {
+		tmdev->sensor[i].tmdev = tmdev;
+		tmdev->sensor[i].id = i;
+		tzd = devm_thermal_zone_of_sensor_register(tmdev->dev, i,
+							   &tmdev->sensor[i],
+							   &tsens_of_ops);
+		if (IS_ERR(tzd))
+			continue;
+		tmdev->sensor[i].tzd = tzd;
+		if (tmdev->ops->enable)
+			tmdev->ops->enable(tmdev, i);
+	}
+	return 0;
+}
+
+static int tsens_probe(struct platform_device *pdev)
+{
+	int ret, i;
+	struct device *dev;
+	struct device_node *np;
+	struct tsens_sensor *s;
+	struct tsens_device *tmdev;
+	const struct tsens_data *data;
+	const struct of_device_id *id;
+
+	if (pdev->dev.of_node)
+		dev = &pdev->dev;
+	else
+		dev = pdev->dev.parent;
+
+	np = dev->of_node;
+
+	id = of_match_node(tsens_table, np);
+	if (!id)
+		return -EINVAL;
+
+	data = id->data;
+
+	if (data->num_sensors <= 0) {
+		dev_err(dev, "invalid number of sensors\n");
+		return -EINVAL;
+	}
+
+	tmdev = devm_kzalloc(dev, sizeof(*tmdev) +
+			     data->num_sensors * sizeof(*s), GFP_KERNEL);
+	if (!tmdev)
+		return -ENOMEM;
+
+	tmdev->dev = dev;
+	tmdev->num_sensors = data->num_sensors;
+	tmdev->ops = data->ops;
+	for (i = 0;  i < tmdev->num_sensors; i++) {
+		if (data->hw_ids)
+			tmdev->sensor[i].hw_id = data->hw_ids[i];
+		else
+			tmdev->sensor[i].hw_id = i;
+	}
+
+	if (!tmdev->ops || !tmdev->ops->init || !tmdev->ops->get_temp)
+		return -EINVAL;
+
+	ret = tmdev->ops->init(tmdev);
+	if (ret < 0) {
+		dev_err(dev, "tsens init failed\n");
+		return ret;
+	}
+
+	if (tmdev->ops->calibrate) {
+		ret = tmdev->ops->calibrate(tmdev);
+		if (ret < 0) {
+			dev_err(dev, "tsens calibration failed\n");
+			return ret;
+		}
+	}
+
+	ret = tsens_register(tmdev);
+
+	platform_set_drvdata(pdev, tmdev);
+
+	return ret;
+}
+
+static int tsens_remove(struct platform_device *pdev)
+{
+	struct tsens_device *tmdev = platform_get_drvdata(pdev);
+
+	if (tmdev->ops->disable)
+		tmdev->ops->disable(tmdev);
+
+	return 0;
+}
+
+static struct platform_driver tsens_driver = {
+	.probe = tsens_probe,
+	.remove = tsens_remove,
+	.driver = {
+		.name = "qcom-tsens",
+		.pm	= &tsens_pm_ops,
+		.of_match_table = tsens_table,
+	},
+};
+module_platform_driver(tsens_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("QCOM Temperature Sensor driver");
+MODULE_ALIAS("platform:qcom-tsens");