/* * drivers/hwmon/nsa320-hwmon.c * * ZyXEL NSA320 Media Servers * hardware monitoring * * Copyright (C) 2016 Adam Baker * based on a board file driver * Copyright (C) 2012 Peter Schildmann * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License v2 as published by the * Free Software Foundation. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* Tests for error return values rely upon this value being < 0x80 */ #define MAGIC_NUMBER 0x55 /* * The Zyxel hwmon MCU is a Holtek HT46R065 that is factory programmed * to perform temperature and fan speed monitoring. It is read by taking * the active pin low. The 32 bit output word is then clocked onto the * data line. The MSB of the data word is a magic nuber to indicate it * has been read correctly, the next byte is the fan speed (in hundreds * of RPM) and the last two bytes are the temperature (in tenths of a * degree) */ struct nsa320_hwmon { struct mutex update_lock; /* lock GPIO operations */ unsigned long last_updated; /* jiffies */ unsigned long mcu_data; struct gpio_desc *act; struct gpio_desc *clk; struct gpio_desc *data; }; enum nsa320_inputs { NSA320_TEMP = 0, NSA320_FAN = 1, }; static const char * const nsa320_input_names[] = { [NSA320_TEMP] = "System Temperature", [NSA320_FAN] = "Chassis Fan", }; /* * Although this protocol looks similar to SPI the long delay * between the active (aka chip select) signal and the shorter * delay between clock pulses are needed for reliable operation. * The delays provided are taken from the manufacturer kernel, * testing suggest they probably incorporate a reasonable safety * margin. (The single device tested became unreliable if the * delay was reduced to 1/10th of this value.) */ static s32 nsa320_hwmon_update(struct device *dev) { u32 mcu_data; u32 mask; struct nsa320_hwmon *hwmon = dev_get_drvdata(dev); mutex_lock(&hwmon->update_lock); mcu_data = hwmon->mcu_data; if (time_after(jiffies, hwmon->last_updated + HZ) || mcu_data == 0) { gpiod_set_value(hwmon->act, 1); msleep(100); mcu_data = 0; for (mask = BIT(31); mask; mask >>= 1) { gpiod_set_value(hwmon->clk, 0); usleep_range(100, 200); gpiod_set_value(hwmon->clk, 1); usleep_range(100, 200); if (gpiod_get_value(hwmon->data)) mcu_data |= mask; } gpiod_set_value(hwmon->act, 0); dev_dbg(dev, "Read raw MCU data %08x\n", mcu_data); if ((mcu_data >> 24) != MAGIC_NUMBER) { dev_dbg(dev, "Read invalid MCU data %08x\n", mcu_data); mcu_data = -EIO; } else { hwmon->mcu_data = mcu_data; hwmon->last_updated = jiffies; } } mutex_unlock(&hwmon->update_lock); return mcu_data; } static ssize_t show_label(struct device *dev, struct device_attribute *attr, char *buf) { int channel = to_sensor_dev_attr(attr)->index; return sprintf(buf, "%s\n", nsa320_input_names[channel]); } static ssize_t temp1_input_show(struct device *dev, struct device_attribute *attr, char *buf) { s32 mcu_data = nsa320_hwmon_update(dev); if (mcu_data < 0) return mcu_data; return sprintf(buf, "%d\n", (mcu_data & 0xffff) * 100); } static ssize_t fan1_input_show(struct device *dev, struct device_attribute *attr, char *buf) { s32 mcu_data = nsa320_hwmon_update(dev); if (mcu_data < 0) return mcu_data; return sprintf(buf, "%d\n", ((mcu_data & 0xff0000) >> 16) * 100); } static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_label, NULL, NSA320_TEMP); static DEVICE_ATTR_RO(temp1_input); static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, show_label, NULL, NSA320_FAN); static DEVICE_ATTR_RO(fan1_input); static struct attribute *nsa320_attrs[] = { &sensor_dev_attr_temp1_label.dev_attr.attr, &dev_attr_temp1_input.attr, &sensor_dev_attr_fan1_label.dev_attr.attr, &dev_attr_fan1_input.attr, NULL }; ATTRIBUTE_GROUPS(nsa320); static const struct of_device_id of_nsa320_hwmon_match[] = { { .compatible = "zyxel,nsa320-mcu", }, { }, }; static int nsa320_hwmon_probe(struct platform_device *pdev) { struct nsa320_hwmon *hwmon; struct device *classdev; hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL); if (!hwmon) return -ENOMEM; /* Look up the GPIO pins to use */ hwmon->act = devm_gpiod_get(&pdev->dev, "act", GPIOD_OUT_LOW); if (IS_ERR(hwmon->act)) return PTR_ERR(hwmon->act); hwmon->clk = devm_gpiod_get(&pdev->dev, "clk", GPIOD_OUT_HIGH); if (IS_ERR(hwmon->clk)) return PTR_ERR(hwmon->clk); hwmon->data = devm_gpiod_get(&pdev->dev, "data", GPIOD_IN); if (IS_ERR(hwmon->data)) return PTR_ERR(hwmon->data); mutex_init(&hwmon->update_lock); classdev = devm_hwmon_device_register_with_groups(&pdev->dev, "nsa320", hwmon, nsa320_groups); return PTR_ERR_OR_ZERO(classdev); } /* All allocations use devres so remove() is not needed. */ static struct platform_driver nsa320_hwmon_driver = { .probe = nsa320_hwmon_probe, .driver = { .name = "nsa320-hwmon", .of_match_table = of_match_ptr(of_nsa320_hwmon_match), }, }; module_platform_driver(nsa320_hwmon_driver); MODULE_DEVICE_TABLE(of, of_nsa320_hwmon_match); MODULE_AUTHOR("Peter Schildmann "); MODULE_AUTHOR("Adam Baker "); MODULE_DESCRIPTION("NSA320 Hardware Monitoring"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:nsa320-hwmon");