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1// SPDX-License-Identifier: GPL-2.0-or-later2/* Lantiq cpu temperature sensor driver3 *4 * Copyright (C) 2017 Florian Eckert <fe@dev.tdt.de>5 */6 7#include <linux/bitops.h>8#include <linux/delay.h>9#include <linux/hwmon.h>10#include <linux/hwmon-sysfs.h>11#include <linux/init.h>12#include <linux/mod_devicetable.h>13#include <linux/module.h>14#include <linux/platform_device.h>15 16#include <lantiq_soc.h>17 18/* gphy1 configuration register contains cpu temperature */19#define CGU_GPHY1_CR 0x004020#define CGU_TEMP_PD BIT(19)21 22static void ltq_cputemp_enable(void)23{24 ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR);25}26 27static void ltq_cputemp_disable(void *data)28{29 ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR);30}31 32static int ltq_read(struct device *dev, enum hwmon_sensor_types type,33 u32 attr, int channel, long *temp)34{35 int value;36 37 switch (attr) {38 case hwmon_temp_input:39 /* get the temperature including one decimal place */40 value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF;41 value = value * 5;42 /* range -38 to +154 °C, register value zero is -38.0 °C */43 value -= 380;44 /* scale temp to millidegree */45 value = value * 100;46 break;47 default:48 return -EOPNOTSUPP;49 }50 51 *temp = value;52 return 0;53}54 55static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type,56 u32 attr, int channel)57{58 if (type != hwmon_temp)59 return 0;60 61 switch (attr) {62 case hwmon_temp_input:63 return 0444;64 default:65 return 0;66 }67}68 69static const struct hwmon_channel_info * const ltq_info[] = {70 HWMON_CHANNEL_INFO(chip,71 HWMON_C_REGISTER_TZ),72 HWMON_CHANNEL_INFO(temp,73 HWMON_T_INPUT),74 NULL75};76 77static const struct hwmon_ops ltq_hwmon_ops = {78 .is_visible = ltq_is_visible,79 .read = ltq_read,80};81 82static const struct hwmon_chip_info ltq_chip_info = {83 .ops = <q_hwmon_ops,84 .info = ltq_info,85};86 87static int ltq_cputemp_probe(struct platform_device *pdev)88{89 struct device *hwmon_dev;90 int err = 0;91 92 /* available on vr9 v1.2 SoCs only */93 if (ltq_soc_type() != SOC_TYPE_VR9_2)94 return -ENODEV;95 96 err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL);97 if (err)98 return err;99 100 ltq_cputemp_enable();101 102 hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,103 "ltq_cputemp",104 NULL,105 <q_chip_info,106 NULL);107 108 if (IS_ERR(hwmon_dev)) {109 dev_err(&pdev->dev, "Failed to register as hwmon device");110 return PTR_ERR(hwmon_dev);111 }112 113 return 0;114}115 116const struct of_device_id ltq_cputemp_match[] = {117 { .compatible = "lantiq,cputemp" },118 {},119};120MODULE_DEVICE_TABLE(of, ltq_cputemp_match);121 122static struct platform_driver ltq_cputemp_driver = {123 .probe = ltq_cputemp_probe,124 .driver = {125 .name = "ltq-cputemp",126 .of_match_table = ltq_cputemp_match,127 },128};129 130module_platform_driver(ltq_cputemp_driver);131 132MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>");133MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver");134MODULE_LICENSE("GPL");135