1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * ChromeOS EC driver for hwmon 4 * 5 * Copyright (C) 2024 Thomas Weißschuh <linux@weissschuh.net> 6 */ 7 8 #include <linux/device.h> 9 #include <linux/hwmon.h> 10 #include <linux/mod_devicetable.h> 11 #include <linux/module.h> 12 #include <linux/platform_device.h> 13 #include <linux/platform_data/cros_ec_commands.h> 14 #include <linux/platform_data/cros_ec_proto.h> 15 #include <linux/types.h> 16 #include <linux/units.h> 17 18 #define DRV_NAME "cros-ec-hwmon" 19 20 struct cros_ec_hwmon_priv { 21 struct cros_ec_device *cros_ec; 22 const char *temp_sensor_names[EC_TEMP_SENSOR_ENTRIES + EC_TEMP_SENSOR_B_ENTRIES]; 23 u8 usable_fans; 24 }; 25 26 static int cros_ec_hwmon_read_fan_speed(struct cros_ec_device *cros_ec, u8 index, u16 *speed) 27 { 28 int ret; 29 __le16 __speed; 30 31 ret = cros_ec_cmd_readmem(cros_ec, EC_MEMMAP_FAN + index * 2, 2, &__speed); 32 if (ret < 0) 33 return ret; 34 35 *speed = le16_to_cpu(__speed); 36 return 0; 37 } 38 39 static int cros_ec_hwmon_read_temp(struct cros_ec_device *cros_ec, u8 index, u8 *temp) 40 { 41 unsigned int offset; 42 int ret; 43 44 if (index < EC_TEMP_SENSOR_ENTRIES) 45 offset = EC_MEMMAP_TEMP_SENSOR + index; 46 else 47 offset = EC_MEMMAP_TEMP_SENSOR_B + index - EC_TEMP_SENSOR_ENTRIES; 48 49 ret = cros_ec_cmd_readmem(cros_ec, offset, 1, temp); 50 if (ret < 0) 51 return ret; 52 return 0; 53 } 54 55 static bool cros_ec_hwmon_is_error_fan(u16 speed) 56 { 57 return speed == EC_FAN_SPEED_NOT_PRESENT || speed == EC_FAN_SPEED_STALLED; 58 } 59 60 static bool cros_ec_hwmon_is_error_temp(u8 temp) 61 { 62 return temp == EC_TEMP_SENSOR_NOT_PRESENT || 63 temp == EC_TEMP_SENSOR_ERROR || 64 temp == EC_TEMP_SENSOR_NOT_POWERED || 65 temp == EC_TEMP_SENSOR_NOT_CALIBRATED; 66 } 67 68 static long cros_ec_hwmon_temp_to_millicelsius(u8 temp) 69 { 70 return kelvin_to_millicelsius((((long)temp) + EC_TEMP_SENSOR_OFFSET)); 71 } 72 73 static int cros_ec_hwmon_read(struct device *dev, enum hwmon_sensor_types type, 74 u32 attr, int channel, long *val) 75 { 76 struct cros_ec_hwmon_priv *priv = dev_get_drvdata(dev); 77 int ret = -EOPNOTSUPP; 78 u16 speed; 79 u8 temp; 80 81 if (type == hwmon_fan) { 82 if (attr == hwmon_fan_input) { 83 ret = cros_ec_hwmon_read_fan_speed(priv->cros_ec, channel, &speed); 84 if (ret == 0) { 85 if (cros_ec_hwmon_is_error_fan(speed)) 86 ret = -ENODATA; 87 else 88 *val = speed; 89 } 90 } else if (attr == hwmon_fan_fault) { 91 ret = cros_ec_hwmon_read_fan_speed(priv->cros_ec, channel, &speed); 92 if (ret == 0) 93 *val = cros_ec_hwmon_is_error_fan(speed); 94 } 95 } else if (type == hwmon_temp) { 96 if (attr == hwmon_temp_input) { 97 ret = cros_ec_hwmon_read_temp(priv->cros_ec, channel, &temp); 98 if (ret == 0) { 99 if (cros_ec_hwmon_is_error_temp(temp)) 100 ret = -ENODATA; 101 else 102 *val = cros_ec_hwmon_temp_to_millicelsius(temp); 103 } 104 } else if (attr == hwmon_temp_fault) { 105 ret = cros_ec_hwmon_read_temp(priv->cros_ec, channel, &temp); 106 if (ret == 0) 107 *val = cros_ec_hwmon_is_error_temp(temp); 108 } 109 } 110 111 return ret; 112 } 113 114 static int cros_ec_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type, 115 u32 attr, int channel, const char **str) 116 { 117 struct cros_ec_hwmon_priv *priv = dev_get_drvdata(dev); 118 119 if (type == hwmon_temp && attr == hwmon_temp_label) { 120 *str = priv->temp_sensor_names[channel]; 121 return 0; 122 } 123 124 return -EOPNOTSUPP; 125 } 126 127 static umode_t cros_ec_hwmon_is_visible(const void *data, enum hwmon_sensor_types type, 128 u32 attr, int channel) 129 { 130 const struct cros_ec_hwmon_priv *priv = data; 131 132 if (type == hwmon_fan) { 133 if (priv->usable_fans & BIT(channel)) 134 return 0444; 135 } else if (type == hwmon_temp) { 136 if (priv->temp_sensor_names[channel]) 137 return 0444; 138 } 139 140 return 0; 141 } 142 143 static const struct hwmon_channel_info * const cros_ec_hwmon_info[] = { 144 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ), 145 HWMON_CHANNEL_INFO(fan, 146 HWMON_F_INPUT | HWMON_F_FAULT, 147 HWMON_F_INPUT | HWMON_F_FAULT, 148 HWMON_F_INPUT | HWMON_F_FAULT, 149 HWMON_F_INPUT | HWMON_F_FAULT), 150 HWMON_CHANNEL_INFO(temp, 151 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 152 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 153 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 154 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 155 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 156 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 157 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 158 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 159 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 160 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 161 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 162 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 163 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 164 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 165 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 166 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 167 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 168 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 169 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 170 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 171 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 172 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 173 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL, 174 HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL), 175 NULL 176 }; 177 178 static const struct hwmon_ops cros_ec_hwmon_ops = { 179 .read = cros_ec_hwmon_read, 180 .read_string = cros_ec_hwmon_read_string, 181 .is_visible = cros_ec_hwmon_is_visible, 182 }; 183 184 static const struct hwmon_chip_info cros_ec_hwmon_chip_info = { 185 .ops = &cros_ec_hwmon_ops, 186 .info = cros_ec_hwmon_info, 187 }; 188 189 static void cros_ec_hwmon_probe_temp_sensors(struct device *dev, struct cros_ec_hwmon_priv *priv, 190 u8 thermal_version) 191 { 192 struct ec_params_temp_sensor_get_info req = {}; 193 struct ec_response_temp_sensor_get_info resp; 194 size_t candidates, i, sensor_name_size; 195 int ret; 196 u8 temp; 197 198 if (thermal_version < 2) 199 candidates = EC_TEMP_SENSOR_ENTRIES; 200 else 201 candidates = ARRAY_SIZE(priv->temp_sensor_names); 202 203 for (i = 0; i < candidates; i++) { 204 if (cros_ec_hwmon_read_temp(priv->cros_ec, i, &temp) < 0) 205 continue; 206 207 if (temp == EC_TEMP_SENSOR_NOT_PRESENT) 208 continue; 209 210 req.id = i; 211 ret = cros_ec_cmd(priv->cros_ec, 0, EC_CMD_TEMP_SENSOR_GET_INFO, 212 &req, sizeof(req), &resp, sizeof(resp)); 213 if (ret < 0) 214 continue; 215 216 sensor_name_size = strnlen(resp.sensor_name, sizeof(resp.sensor_name)); 217 priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%.*s", 218 (int)sensor_name_size, 219 resp.sensor_name); 220 } 221 } 222 223 static void cros_ec_hwmon_probe_fans(struct cros_ec_hwmon_priv *priv) 224 { 225 u16 speed; 226 size_t i; 227 int ret; 228 229 for (i = 0; i < EC_FAN_SPEED_ENTRIES; i++) { 230 ret = cros_ec_hwmon_read_fan_speed(priv->cros_ec, i, &speed); 231 if (ret == 0 && speed != EC_FAN_SPEED_NOT_PRESENT) 232 priv->usable_fans |= BIT(i); 233 } 234 } 235 236 static int cros_ec_hwmon_probe(struct platform_device *pdev) 237 { 238 struct device *dev = &pdev->dev; 239 struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent); 240 struct cros_ec_device *cros_ec = ec_dev->ec_dev; 241 struct cros_ec_hwmon_priv *priv; 242 struct device *hwmon_dev; 243 u8 thermal_version; 244 int ret; 245 246 ret = cros_ec_cmd_readmem(cros_ec, EC_MEMMAP_THERMAL_VERSION, 1, &thermal_version); 247 if (ret < 0) 248 return ret; 249 250 /* Covers both fan and temp sensors */ 251 if (thermal_version == 0) 252 return -ENODEV; 253 254 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 255 if (!priv) 256 return -ENOMEM; 257 258 priv->cros_ec = cros_ec; 259 260 cros_ec_hwmon_probe_temp_sensors(dev, priv, thermal_version); 261 cros_ec_hwmon_probe_fans(priv); 262 263 hwmon_dev = devm_hwmon_device_register_with_info(dev, "cros_ec", priv, 264 &cros_ec_hwmon_chip_info, NULL); 265 266 return PTR_ERR_OR_ZERO(hwmon_dev); 267 } 268 269 static const struct platform_device_id cros_ec_hwmon_id[] = { 270 { DRV_NAME, 0 }, 271 {} 272 }; 273 274 static struct platform_driver cros_ec_hwmon_driver = { 275 .driver.name = DRV_NAME, 276 .probe = cros_ec_hwmon_probe, 277 .id_table = cros_ec_hwmon_id, 278 }; 279 module_platform_driver(cros_ec_hwmon_driver); 280 281 MODULE_DEVICE_TABLE(platform, cros_ec_hwmon_id); 282 MODULE_DESCRIPTION("ChromeOS EC Hardware Monitoring Driver"); 283 MODULE_AUTHOR("Thomas Weißschuh <linux@weissschuh.net"); 284 MODULE_LICENSE("GPL"); 285