// SPDX-License-Identifier: GPL-2.0+ /* * Thermal sensor subsystem driver for Surface System Aggregator Module (SSAM). * * Copyright (C) 2022-2023 Maximilian Luz */ #include #include #include #include #include #include #include /* -- SAM interface. -------------------------------------------------------- */ /* * Available sensors are indicated by a 16-bit bitfield, where a 1 marks the * presence of a sensor. So we have at most 16 possible sensors/channels. */ #define SSAM_TMP_SENSOR_MAX_COUNT 16 /* * All names observed so far are 6 characters long, but there's only * zeros after the name, so perhaps they can be longer. This number reflects * the maximum zero-padded space observed in the returned buffer. */ #define SSAM_TMP_SENSOR_NAME_LENGTH 18 struct ssam_tmp_get_name_rsp { __le16 unknown1; char unknown2; char name[SSAM_TMP_SENSOR_NAME_LENGTH]; } __packed; static_assert(sizeof(struct ssam_tmp_get_name_rsp) == 21); SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_tmp_get_available_sensors, __le16, { .target_category = SSAM_SSH_TC_TMP, .command_id = 0x04, }); SSAM_DEFINE_SYNC_REQUEST_MD_R(__ssam_tmp_get_temperature, __le16, { .target_category = SSAM_SSH_TC_TMP, .command_id = 0x01, }); SSAM_DEFINE_SYNC_REQUEST_MD_R(__ssam_tmp_get_name, struct ssam_tmp_get_name_rsp, { .target_category = SSAM_SSH_TC_TMP, .command_id = 0x0e, }); static int ssam_tmp_get_available_sensors(struct ssam_device *sdev, s16 *sensors) { __le16 sensors_le; int status; status = __ssam_tmp_get_available_sensors(sdev, &sensors_le); if (status) return status; *sensors = le16_to_cpu(sensors_le); return 0; } static int ssam_tmp_get_temperature(struct ssam_device *sdev, u8 iid, long *temperature) { __le16 temp_le; int status; status = __ssam_tmp_get_temperature(sdev->ctrl, sdev->uid.target, iid, &temp_le); if (status) return status; /* Convert 1/10 °K to 1/1000 °C */ *temperature = (le16_to_cpu(temp_le) - 2731) * 100L; return 0; } static int ssam_tmp_get_name(struct ssam_device *sdev, u8 iid, char *buf, size_t buf_len) { struct ssam_tmp_get_name_rsp name_rsp; int status; status = __ssam_tmp_get_name(sdev->ctrl, sdev->uid.target, iid, &name_rsp); if (status) return status; /* * This should not fail unless the name in the returned struct is not * null-terminated or someone changed something in the struct * definitions above, since our buffer and struct have the same * capacity by design. So if this fails, log an error message. Since * the more likely cause is that the returned string isn't * null-terminated, we might have received garbage (as opposed to just * an incomplete string), so also fail the function. */ status = strscpy(buf, name_rsp.name, buf_len); if (status < 0) { dev_err(&sdev->dev, "received non-null-terminated sensor name string\n"); return status; } return 0; } /* -- Driver.---------------------------------------------------------------- */ struct ssam_temp { struct ssam_device *sdev; s16 sensors; char names[SSAM_TMP_SENSOR_MAX_COUNT][SSAM_TMP_SENSOR_NAME_LENGTH]; }; static umode_t ssam_temp_hwmon_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) { const struct ssam_temp *ssam_temp = data; if (!(ssam_temp->sensors & BIT(channel))) return 0; return 0444; } static int ssam_temp_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *value) { const struct ssam_temp *ssam_temp = dev_get_drvdata(dev); return ssam_tmp_get_temperature(ssam_temp->sdev, channel + 1, value); } static int ssam_temp_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, const char **str) { const struct ssam_temp *ssam_temp = dev_get_drvdata(dev); *str = ssam_temp->names[channel]; return 0; } static const struct hwmon_channel_info * const ssam_temp_hwmon_info[] = { HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ), HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL), NULL }; static const struct hwmon_ops ssam_temp_hwmon_ops = { .is_visible = ssam_temp_hwmon_is_visible, .read = ssam_temp_hwmon_read, .read_string = ssam_temp_hwmon_read_string, }; static const struct hwmon_chip_info ssam_temp_hwmon_chip_info = { .ops = &ssam_temp_hwmon_ops, .info = ssam_temp_hwmon_info, }; static int ssam_temp_probe(struct ssam_device *sdev) { struct ssam_temp *ssam_temp; struct device *hwmon_dev; s16 sensors; int channel; int status; status = ssam_tmp_get_available_sensors(sdev, &sensors); if (status) return status; ssam_temp = devm_kzalloc(&sdev->dev, sizeof(*ssam_temp), GFP_KERNEL); if (!ssam_temp) return -ENOMEM; ssam_temp->sdev = sdev; ssam_temp->sensors = sensors; /* Retrieve the name for each available sensor. */ for (channel = 0; channel < SSAM_TMP_SENSOR_MAX_COUNT; channel++) { if (!(sensors & BIT(channel))) continue; status = ssam_tmp_get_name(sdev, channel + 1, ssam_temp->names[channel], SSAM_TMP_SENSOR_NAME_LENGTH); if (status) return status; } hwmon_dev = devm_hwmon_device_register_with_info(&sdev->dev, "surface_thermal", ssam_temp, &ssam_temp_hwmon_chip_info, NULL); return PTR_ERR_OR_ZERO(hwmon_dev); } static const struct ssam_device_id ssam_temp_match[] = { { SSAM_SDEV(TMP, SAM, 0x00, 0x02) }, { }, }; MODULE_DEVICE_TABLE(ssam, ssam_temp_match); static struct ssam_device_driver ssam_temp = { .probe = ssam_temp_probe, .match_table = ssam_temp_match, .driver = { .name = "surface_temp", .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, }; module_ssam_device_driver(ssam_temp); MODULE_AUTHOR("Maximilian Luz "); MODULE_DESCRIPTION("Thermal sensor subsystem driver for Surface System Aggregator Module"); MODULE_LICENSE("GPL");