1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Lantiq cpu temperature sensor driver 3 * 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/module.h> 13 #include <linux/of_device.h> 14 15 #include <lantiq_soc.h> 16 17 /* gphy1 configuration register contains cpu temperature */ 18 #define CGU_GPHY1_CR 0x0040 19 #define CGU_TEMP_PD BIT(19) 20 21 static void ltq_cputemp_enable(void) 22 { 23 ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR); 24 } 25 26 static void ltq_cputemp_disable(void *data) 27 { 28 ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR); 29 } 30 31 static int ltq_read(struct device *dev, enum hwmon_sensor_types type, 32 u32 attr, int channel, long *temp) 33 { 34 int value; 35 36 switch (attr) { 37 case hwmon_temp_input: 38 /* get the temperature including one decimal place */ 39 value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF; 40 value = value * 5; 41 /* range -38 to +154 °C, register value zero is -38.0 °C */ 42 value -= 380; 43 /* scale temp to millidegree */ 44 value = value * 100; 45 break; 46 default: 47 return -EOPNOTSUPP; 48 } 49 50 *temp = value; 51 return 0; 52 } 53 54 static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type, 55 u32 attr, int channel) 56 { 57 if (type != hwmon_temp) 58 return 0; 59 60 switch (attr) { 61 case hwmon_temp_input: 62 return 0444; 63 default: 64 return 0; 65 } 66 } 67 68 static const struct hwmon_channel_info * const ltq_info[] = { 69 HWMON_CHANNEL_INFO(chip, 70 HWMON_C_REGISTER_TZ), 71 HWMON_CHANNEL_INFO(temp, 72 HWMON_T_INPUT), 73 NULL 74 }; 75 76 static const struct hwmon_ops ltq_hwmon_ops = { 77 .is_visible = ltq_is_visible, 78 .read = ltq_read, 79 }; 80 81 static const struct hwmon_chip_info ltq_chip_info = { 82 .ops = <q_hwmon_ops, 83 .info = ltq_info, 84 }; 85 86 static int ltq_cputemp_probe(struct platform_device *pdev) 87 { 88 struct device *hwmon_dev; 89 int err = 0; 90 91 /* available on vr9 v1.2 SoCs only */ 92 if (ltq_soc_type() != SOC_TYPE_VR9_2) 93 return -ENODEV; 94 95 err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL); 96 if (err) 97 return err; 98 99 ltq_cputemp_enable(); 100 101 hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, 102 "ltq_cputemp", 103 NULL, 104 <q_chip_info, 105 NULL); 106 107 if (IS_ERR(hwmon_dev)) { 108 dev_err(&pdev->dev, "Failed to register as hwmon device"); 109 return PTR_ERR(hwmon_dev); 110 } 111 112 return 0; 113 } 114 115 const struct of_device_id ltq_cputemp_match[] = { 116 { .compatible = "lantiq,cputemp" }, 117 {}, 118 }; 119 MODULE_DEVICE_TABLE(of, ltq_cputemp_match); 120 121 static struct platform_driver ltq_cputemp_driver = { 122 .probe = ltq_cputemp_probe, 123 .driver = { 124 .name = "ltq-cputemp", 125 .of_match_table = ltq_cputemp_match, 126 }, 127 }; 128 129 module_platform_driver(ltq_cputemp_driver); 130 131 MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>"); 132 MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver"); 133 MODULE_LICENSE("GPL"); 134