MIPS: Loongson-3: Add CPU Hwmon platform driver

This add CPU Hwmon (temperature sensor) platform driver for Loongson-3.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/9617/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 234 insertions, 0 deletions

diff --git a/drivers/platform/mips/Kconfig b/drivers/platform/mips/Kconfig
new file mode 100644
index 000000000000..b3ae30a4c67b
--- /dev/null
+++ b/drivers/platform/mips/Kconfig
@@ -0,0 +1,26 @@
+#
+# MIPS Platform Specific Drivers
+#
+
+menuconfig MIPS_PLATFORM_DEVICES
+	bool "MIPS Platform Specific Device Drivers"
+	default y
+	help
+	  Say Y here to get to see options for device drivers of various
+	  MIPS platforms, including vendor-specific netbook/laptop/desktop
+	  extension and hardware monitor drivers. This option itself does
+	  not add any kernel code.
+
+	  If you say N, all options in this submenu will be skipped and disabled.
+
+if MIPS_PLATFORM_DEVICES
+
+config CPU_HWMON
+	tristate "Loongson CPU HWMon Driver"
+	depends on LOONGSON_MACH3X
+	select HWMON
+	default y
+	help
+	  Loongson-3A/3B CPU Hwmon (temperature sensor) driver.
+
+endif # MIPS_PLATFORM_DEVICES
diff --git a/drivers/platform/mips/Makefile b/drivers/platform/mips/Makefile
new file mode 100644
index 000000000000..8dfd03924c37
--- /dev/null
+++ b/drivers/platform/mips/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_CPU_HWMON) += cpu_hwmon.o
diff --git a/drivers/platform/mips/cpu_hwmon.c b/drivers/platform/mips/cpu_hwmon.c
new file mode 100644
index 000000000000..0f6c63e17049
--- /dev/null
+++ b/drivers/platform/mips/cpu_hwmon.c
@@ -0,0 +1,207 @@
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/reboot.h>
+#include <linux/jiffies.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+#include <loongson.h>
+#include <boot_param.h>
+#include <loongson_hwmon.h>
+
+/*
+ * Loongson-3 series cpu has two sensors inside,
+ * each of them from 0 to 255,
+ * if more than 127, that is dangerous.
+ * here only provide sensor1 data, because it always hot than sensor0
+ */
+int loongson3_cpu_temp(int cpu)
+{
+	u32 reg;
+
+	reg = LOONGSON_CHIPTEMP(cpu);
+	if (loongson_sysconf.cputype == Loongson_3A)
+		reg = (reg >> 8) & 0xff;
+	else if (loongson_sysconf.cputype == Loongson_3B)
+		reg = ((reg >> 8) & 0xff) - 100;
+
+	return (int)reg * 1000;
+}
+
+static struct device *cpu_hwmon_dev;
+
+static ssize_t get_hwmon_name(struct device *dev,
+			struct device_attribute *attr, char *buf);
+static SENSOR_DEVICE_ATTR(name, S_IRUGO, get_hwmon_name, NULL, 0);
+
+static struct attribute *cpu_hwmon_attributes[] = {
+	&sensor_dev_attr_name.dev_attr.attr,
+	NULL
+};
+
+/* Hwmon device attribute group */
+static struct attribute_group cpu_hwmon_attribute_group = {
+	.attrs = cpu_hwmon_attributes,
+};
+
+/* Hwmon device get name */
+static ssize_t get_hwmon_name(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "cpu-hwmon\n");
+}
+
+static ssize_t get_cpu0_temp(struct device *dev,
+			struct device_attribute *attr, char *buf);
+static ssize_t get_cpu1_temp(struct device *dev,
+			struct device_attribute *attr, char *buf);
+static ssize_t cpu0_temp_label(struct device *dev,
+			struct device_attribute *attr, char *buf);
+static ssize_t cpu1_temp_label(struct device *dev,
+			struct device_attribute *attr, char *buf);
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, get_cpu0_temp, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, cpu0_temp_label, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, get_cpu1_temp, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, cpu1_temp_label, NULL, 2);
+
+static const struct attribute *hwmon_cputemp1[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_label.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute *hwmon_cputemp2[] = {
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_temp2_label.dev_attr.attr,
+	NULL
+};
+
+static ssize_t cpu0_temp_label(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "CPU 0 Temprature\n");
+}
+
+static ssize_t cpu1_temp_label(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "CPU 1 Temprature\n");
+}
+
+static ssize_t get_cpu0_temp(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	int value = loongson3_cpu_temp(0);
+	return sprintf(buf, "%d\n", value);
+}
+
+static ssize_t get_cpu1_temp(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	int value = loongson3_cpu_temp(1);
+	return sprintf(buf, "%d\n", value);
+}
+
+static int create_sysfs_cputemp_files(struct kobject *kobj)
+{
+	int ret;
+
+	ret = sysfs_create_files(kobj, hwmon_cputemp1);
+	if (ret)
+		goto sysfs_create_temp1_fail;
+
+	if (loongson_sysconf.nr_cpus <= loongson_sysconf.cores_per_package)
+		return 0;
+
+	ret = sysfs_create_files(kobj, hwmon_cputemp2);
+	if (ret)
+		goto sysfs_create_temp2_fail;
+
+	return 0;
+
+sysfs_create_temp2_fail:
+	sysfs_remove_files(kobj, hwmon_cputemp1);
+
+sysfs_create_temp1_fail:
+	return -1;
+}
+
+static void remove_sysfs_cputemp_files(struct kobject *kobj)
+{
+	sysfs_remove_files(&cpu_hwmon_dev->kobj, hwmon_cputemp1);
+
+	if (loongson_sysconf.nr_cpus > loongson_sysconf.cores_per_package)
+		sysfs_remove_files(&cpu_hwmon_dev->kobj, hwmon_cputemp2);
+}
+
+#define CPU_THERMAL_THRESHOLD 90000
+static struct delayed_work thermal_work;
+
+static void do_thermal_timer(struct work_struct *work)
+{
+	int value = loongson3_cpu_temp(0);
+	if (value <= CPU_THERMAL_THRESHOLD)
+		schedule_delayed_work(&thermal_work, msecs_to_jiffies(5000));
+	else
+		orderly_poweroff(true);
+}
+
+static int __init loongson_hwmon_init(void)
+{
+	int ret;
+
+	pr_info("Loongson Hwmon Enter...\n");
+
+	cpu_hwmon_dev = hwmon_device_register(NULL);
+	if (IS_ERR(cpu_hwmon_dev)) {
+		ret = -ENOMEM;
+		pr_err("hwmon_device_register fail!\n");
+		goto fail_hwmon_device_register;
+	}
+
+	ret = sysfs_create_group(&cpu_hwmon_dev->kobj,
+				&cpu_hwmon_attribute_group);
+	if (ret) {
+		pr_err("fail to create loongson hwmon!\n");
+		goto fail_sysfs_create_group_hwmon;
+	}
+
+	ret = create_sysfs_cputemp_files(&cpu_hwmon_dev->kobj);
+	if (ret) {
+		pr_err("fail to create cpu temprature interface!\n");
+		goto fail_create_sysfs_cputemp_files;
+	}
+
+	INIT_DEFERRABLE_WORK(&thermal_work, do_thermal_timer);
+	schedule_delayed_work(&thermal_work, msecs_to_jiffies(20000));
+
+	return ret;
+
+fail_create_sysfs_cputemp_files:
+	sysfs_remove_group(&cpu_hwmon_dev->kobj,
+				&cpu_hwmon_attribute_group);
+
+fail_sysfs_create_group_hwmon:
+	hwmon_device_unregister(cpu_hwmon_dev);
+
+fail_hwmon_device_register:
+	return ret;
+}
+
+static void __exit loongson_hwmon_exit(void)
+{
+	cancel_delayed_work_sync(&thermal_work);
+	remove_sysfs_cputemp_files(&cpu_hwmon_dev->kobj);
+	sysfs_remove_group(&cpu_hwmon_dev->kobj,
+				&cpu_hwmon_attribute_group);
+	hwmon_device_unregister(cpu_hwmon_dev);
+}
+
+module_init(loongson_hwmon_init);
+module_exit(loongson_hwmon_exit);
+
+MODULE_AUTHOR("Yu Xiang <xiangy@lemote.com>");
+MODULE_AUTHOR("Huacai Chen <chenhc@lemote.com>");
+MODULE_DESCRIPTION("Loongson CPU Hwmon driver");
+MODULE_LICENSE("GPL");