1 files changed, 355 insertions, 0 deletions
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
new file mode 100644
index 000000000..65de80bd6
--- /dev/null
+++ b/drivers/hwmon/pwm-fan.c
@@ -0,0 +1,355 @@
+/*
+ * pwm-fan.c - Hwmon driver for fans connected to PWM lines.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ *
+ * Author: Kamil Debski <k.debski@samsung.com>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/sysfs.h>
+#include <linux/thermal.h>
+
+#define MAX_PWM 255
+
+struct pwm_fan_ctx {
+	struct mutex lock;
+	struct pwm_device *pwm;
+	unsigned int pwm_value;
+	unsigned int pwm_fan_state;
+	unsigned int pwm_fan_max_state;
+	unsigned int *pwm_fan_cooling_levels;
+	struct thermal_cooling_device *cdev;
+};
+
+static int  __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
+{
+	unsigned long period;
+	int ret = 0;
+	struct pwm_state state = { };
+
+	mutex_lock(&ctx->lock);
+	if (ctx->pwm_value == pwm)
+		goto exit_set_pwm_err;
+
+	pwm_init_state(ctx->pwm, &state);
+	period = ctx->pwm->args.period;
+	state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
+	state.enabled = pwm ? true : false;
+
+	ret = pwm_apply_state(ctx->pwm, &state);
+	if (!ret)
+		ctx->pwm_value = pwm;
+exit_set_pwm_err:
+	mutex_unlock(&ctx->lock);
+	return ret;
+}
+
+static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
+{
+	int i;
+
+	for (i = 0; i < ctx->pwm_fan_max_state; ++i)
+		if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
+			break;
+
+	ctx->pwm_fan_state = i;
+}
+
+static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
+		       const char *buf, size_t count)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+	unsigned long pwm;
+	int ret;
+
+	if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM)
+		return -EINVAL;
+
+	ret = __set_pwm(ctx, pwm);
+	if (ret)
+		return ret;
+
+	pwm_fan_update_state(ctx, pwm);
+	return count;
+}
+
+static ssize_t show_pwm(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", ctx->pwm_value);
+}
+
+
+static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0);
+
+static struct attribute *pwm_fan_attrs[] = {
+	&sensor_dev_attr_pwm1.dev_attr.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(pwm_fan);
+
+/* thermal cooling device callbacks */
+static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	struct pwm_fan_ctx *ctx = cdev->devdata;
+
+	if (!ctx)
+		return -EINVAL;
+
+	*state = ctx->pwm_fan_max_state;
+
+	return 0;
+}
+
+static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	struct pwm_fan_ctx *ctx = cdev->devdata;
+
+	if (!ctx)
+		return -EINVAL;
+
+	*state = ctx->pwm_fan_state;
+
+	return 0;
+}
+
+static int
+pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
+{
+	struct pwm_fan_ctx *ctx = cdev->devdata;
+	int ret;
+
+	if (!ctx || (state > ctx->pwm_fan_max_state))
+		return -EINVAL;
+
+	if (state == ctx->pwm_fan_state)
+		return 0;
+
+	ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
+	if (ret) {
+		dev_err(&cdev->device, "Cannot set pwm!\n");
+		return ret;
+	}
+
+	ctx->pwm_fan_state = state;
+
+	return ret;
+}
+
+static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
+	.get_max_state = pwm_fan_get_max_state,
+	.get_cur_state = pwm_fan_get_cur_state,
+	.set_cur_state = pwm_fan_set_cur_state,
+};
+
+static int pwm_fan_of_get_cooling_data(struct device *dev,
+				       struct pwm_fan_ctx *ctx)
+{
+	struct device_node *np = dev->of_node;
+	int num, i, ret;
+
+	if (!of_find_property(np, "cooling-levels", NULL))
+		return 0;
+
+	ret = of_property_count_u32_elems(np, "cooling-levels");
+	if (ret <= 0) {
+		dev_err(dev, "Wrong data!\n");
+		return ret ? : -EINVAL;
+	}
+
+	num = ret;
+	ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
+						   GFP_KERNEL);
+	if (!ctx->pwm_fan_cooling_levels)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_array(np, "cooling-levels",
+					 ctx->pwm_fan_cooling_levels, num);
+	if (ret) {
+		dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
+		return ret;
+	}
+
+	for (i = 0; i < num; i++) {
+		if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
+			dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
+				ctx->pwm_fan_cooling_levels[i], MAX_PWM);
+			return -EINVAL;
+		}
+	}
+
+	ctx->pwm_fan_max_state = num - 1;
+
+	return 0;
+}
+
+static int pwm_fan_probe(struct platform_device *pdev)
+{
+	struct thermal_cooling_device *cdev;
+	struct pwm_fan_ctx *ctx;
+	struct device *hwmon;
+	int ret;
+	struct pwm_state state = { };
+
+	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	mutex_init(&ctx->lock);
+
+	ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL);
+	if (IS_ERR(ctx->pwm)) {
+		ret = PTR_ERR(ctx->pwm);
+
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Could not get PWM: %d\n", ret);
+
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, ctx);
+
+	ctx->pwm_value = MAX_PWM;
+
+	/* Set duty cycle to maximum allowed and enable PWM output */
+	pwm_init_state(ctx->pwm, &state);
+	state.duty_cycle = ctx->pwm->args.period - 1;
+	state.enabled = true;
+
+	ret = pwm_apply_state(ctx->pwm, &state);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to configure PWM\n");
+		return ret;
+	}
+
+	hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan",
+						       ctx, pwm_fan_groups);
+	if (IS_ERR(hwmon)) {
+		dev_err(&pdev->dev, "Failed to register hwmon device\n");
+		ret = PTR_ERR(hwmon);
+		goto err_pwm_disable;
+	}
+
+	ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx);
+	if (ret)
+		goto err_pwm_disable;
+
+	ctx->pwm_fan_state = ctx->pwm_fan_max_state;
+	if (IS_ENABLED(CONFIG_THERMAL)) {
+		cdev = thermal_of_cooling_device_register(pdev->dev.of_node,
+							  "pwm-fan", ctx,
+							  &pwm_fan_cooling_ops);
+		if (IS_ERR(cdev)) {
+			dev_err(&pdev->dev,
+				"Failed to register pwm-fan as cooling device");
+			ret = PTR_ERR(cdev);
+			goto err_pwm_disable;
+		}
+		ctx->cdev = cdev;
+		thermal_cdev_update(cdev);
+	}
+
+	return 0;
+
+err_pwm_disable:
+	state.enabled = false;
+	pwm_apply_state(ctx->pwm, &state);
+
+	return ret;
+}
+
+static int pwm_fan_remove(struct platform_device *pdev)
+{
+	struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
+
+	thermal_cooling_device_unregister(ctx->cdev);
+	if (ctx->pwm_value)
+		pwm_disable(ctx->pwm);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int pwm_fan_suspend(struct device *dev)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+	struct pwm_args args;
+	int ret;
+
+	pwm_get_args(ctx->pwm, &args);
+
+	if (ctx->pwm_value) {
+		ret = pwm_config(ctx->pwm, 0, args.period);
+		if (ret < 0)
+			return ret;
+
+		pwm_disable(ctx->pwm);
+	}
+
+	return 0;
+}
+
+static int pwm_fan_resume(struct device *dev)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+	struct pwm_args pargs;
+	unsigned long duty;
+	int ret;
+
+	if (ctx->pwm_value == 0)
+		return 0;
+
+	pwm_get_args(ctx->pwm, &pargs);
+	duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
+	ret = pwm_config(ctx->pwm, duty, pargs.period);
+	if (ret)
+		return ret;
+	return pwm_enable(ctx->pwm);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
+
+static const struct of_device_id of_pwm_fan_match[] = {
+	{ .compatible = "pwm-fan", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
+
+static struct platform_driver pwm_fan_driver = {
+	.probe		= pwm_fan_probe,
+	.remove		= pwm_fan_remove,
+	.driver	= {
+		.name		= "pwm-fan",
+		.pm		= &pwm_fan_pm,
+		.of_match_table	= of_pwm_fan_match,
+	},
+};
+
+module_platform_driver(pwm_fan_driver);
+
+MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
+MODULE_ALIAS("platform:pwm-fan");
+MODULE_DESCRIPTION("PWM FAN driver");
+MODULE_LICENSE("GPL");