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Diffstat (limited to 'drivers/hwmon/ltq-cputemp.c')
-rw-r--r--drivers/hwmon/ltq-cputemp.c133
1 files changed, 133 insertions, 0 deletions
diff --git a/drivers/hwmon/ltq-cputemp.c b/drivers/hwmon/ltq-cputemp.c
new file mode 100644
index 000000000..019e770d4
--- /dev/null
+++ b/drivers/hwmon/ltq-cputemp.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Lantiq cpu temperature sensor driver
+ *
+ * Copyright (C) 2017 Florian Eckert <fe@dev.tdt.de>
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+#include <lantiq_soc.h>
+
+/* gphy1 configuration register contains cpu temperature */
+#define CGU_GPHY1_CR 0x0040
+#define CGU_TEMP_PD BIT(19)
+
+static void ltq_cputemp_enable(void)
+{
+ ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR);
+}
+
+static void ltq_cputemp_disable(void *data)
+{
+ ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR);
+}
+
+static int ltq_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *temp)
+{
+ int value;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ /* get the temperature including one decimal place */
+ value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF;
+ value = value * 5;
+ /* range -38 to +154 °C, register value zero is -38.0 °C */
+ value -= 380;
+ /* scale temp to millidegree */
+ value = value * 100;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ *temp = value;
+ return 0;
+}
+
+static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ if (type != hwmon_temp)
+ return 0;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ return 0444;
+ default:
+ return 0;
+ }
+}
+
+static const struct hwmon_channel_info *ltq_info[] = {
+ HWMON_CHANNEL_INFO(chip,
+ HWMON_C_REGISTER_TZ),
+ HWMON_CHANNEL_INFO(temp,
+ HWMON_T_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops ltq_hwmon_ops = {
+ .is_visible = ltq_is_visible,
+ .read = ltq_read,
+};
+
+static const struct hwmon_chip_info ltq_chip_info = {
+ .ops = &ltq_hwmon_ops,
+ .info = ltq_info,
+};
+
+static int ltq_cputemp_probe(struct platform_device *pdev)
+{
+ struct device *hwmon_dev;
+ int err = 0;
+
+ /* available on vr9 v1.2 SoCs only */
+ if (ltq_soc_type() != SOC_TYPE_VR9_2)
+ return -ENODEV;
+
+ err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL);
+ if (err)
+ return err;
+
+ ltq_cputemp_enable();
+
+ hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
+ "ltq_cputemp",
+ NULL,
+ &ltq_chip_info,
+ NULL);
+
+ if (IS_ERR(hwmon_dev)) {
+ dev_err(&pdev->dev, "Failed to register as hwmon device");
+ return PTR_ERR(hwmon_dev);
+ }
+
+ return 0;
+}
+
+const struct of_device_id ltq_cputemp_match[] = {
+ { .compatible = "lantiq,cputemp" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ltq_cputemp_match);
+
+static struct platform_driver ltq_cputemp_driver = {
+ .probe = ltq_cputemp_probe,
+ .driver = {
+ .name = "ltq-cputemp",
+ .of_match_table = ltq_cputemp_match,
+ },
+};
+
+module_platform_driver(ltq_cputemp_driver);
+
+MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>");
+MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver");
+MODULE_LICENSE("GPL");