msm: fan: Add driver to control fan on RB5

Add driver to control fan on QRB5165 with PM8150L gpio10.

Change-Id: I09d4a3f359c952fd81be6149cbc0b9435d53bb9d
Signed-off-by: Peng Wang <penwang@codeaurora.org>

drivers/char/Kconfig

@@ -587,6 +587,14 @@ config ADI
 	  and SSM (Silicon Secured Memory).  Intended consumers of this
 	  driver include crash and makedumpfile.
 
+config RB5_FAN_CONTROLLER
+	tristate "RB5 fan controller driver support"
+	help
+	  The driver supports the fan controller on QRB5165 device.
+	  The driver controls fan with PM8150L gpio10. It outputs
+	  high to the pin, which is defined in device-tree as
+	  qcom,pwr-enable-gpio.
+
 endmenu
 
 config RANDOM_TRUST_CPU

drivers/char/Makefile

@@ -73,3 +73,4 @@ obj-$(CONFIG_VSERVICES_SERIAL_CLIENT)	+= vs_serial_client.o
 CFLAGS_vs_serial_client.o	 += -Werror
 obj-$(CONFIG_VSERVICES_SERIAL_SERVER)	+= vs_serial_server.o
 CFLAGS_vs_serial_server.o	+= -Werror
+obj-$(CONFIG_RB5_FAN_CONTROLLER)	+= rb5_fan.o

drivers/char/rb5_fan.c

@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/**
+ * Driver for control fan on QRB5165.
+ *
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/gpio.h>
+#include <linux/kernel.h>
+
+#define DEV_NAME "rb5_fan"
+
+static int major;
+static struct class *fan_class;
+
+static u32 pwr_enable_gpio;
+
+static const struct file_operations fan_fops = {
+	.owner		= THIS_MODULE,
+};
+
+static int fan_probe(struct platform_device *pdev)
+{
+	struct device *dev = NULL;
+	struct device_node *np = pdev->dev.of_node;
+
+	pr_debug(DEV_NAME ": probe\n");
+
+	major = register_chrdev(0, DEV_NAME, &fan_fops);
+	if (major < 0) {
+		pr_warn(DEV_NAME ": unable to get major %d\n", major);
+		return major;
+	}
+
+	fan_class = class_create(THIS_MODULE, DEV_NAME);
+	if (IS_ERR(fan_class))
+		return PTR_ERR(fan_class);
+
+	dev = device_create(fan_class, NULL, MKDEV(major, 0), NULL, DEV_NAME);
+	if (IS_ERR(dev)) {
+		pr_err(DEV_NAME ": failed to create device %d\n", dev);
+		return PTR_ERR(dev);
+	}
+
+	pwr_enable_gpio = of_get_named_gpio(np, "qcom,pwr-enable-gpio", 0);
+	if (!gpio_is_valid(pwr_enable_gpio)) {
+		pr_err("%s qcom,pwr-enable-gpio not specified\n", __func__);
+		goto error;
+	}
+	if (gpio_request(pwr_enable_gpio, "qcom,pwr-enable-gpio")) {
+		pr_err("qcom,pwr-enable-gpio request failed\n");
+		goto error;
+	}
+	gpio_direction_output(pwr_enable_gpio, 0);
+	gpio_set_value(pwr_enable_gpio, 1);
+	pr_debug("%s gpio:%d set to high\n", __func__, pwr_enable_gpio);
+	return 0;
+
+error:
+	gpio_free(pwr_enable_gpio);
+	return -EINVAL;
+}
+
+static int fan_remove(struct platform_device *pdev)
+{
+	pr_debug(DEV_NAME ": remove\n");
+	gpio_free(pwr_enable_gpio);
+	device_destroy(fan_class, MKDEV(major, 0));
+	class_destroy(fan_class);
+	unregister_chrdev(major, DEV_NAME);
+	return 0;
+}
+
+static const struct of_device_id of_fan_dt_match[] = {
+	{.compatible	= "qcom,rb5_fan_controller"},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, of_fan_dt_match);
+
+static struct platform_driver fan_driver = {
+	.probe	= fan_probe,
+	.remove	= fan_remove,
+	.driver	= {
+		.name	= DEV_NAME,
+		.of_match_table	= of_fan_dt_match,
+	},
+};
+
+static int __init fan_init(void)
+{
+	pr_debug(DEV_NAME ": init\n");
+	return platform_driver_register(&fan_driver);
+}
+
+static void __exit fan_exit(void)
+{
+	pr_debug(DEV_NAME ": exit\n");
+	platform_driver_unregister(&fan_driver);
+}
+
+module_init(fan_init);
+module_exit(fan_exit);
+
+MODULE_DESCRIPTION("Driver to control fan");
+MODULE_LICENSE("GPL v2");