/* * Maxim MAX197 A/D Converter driver * * Copyright (c) 2012 Savoir-faire Linux Inc. * Vivien Didelot <vivien.didelot@savoirfairelinux.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * For further information, see the Documentation/hwmon/max197 file. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/err.h> #include <linux/slab.h> #include <linux/mutex.h> #include <linux/device.h> #include <linux/sysfs.h> #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> #include <linux/platform_device.h> #include <linux/platform_data/max197.h> #define MAX199_LIMIT 4000 /* 4V */ #define MAX197_LIMIT 10000 /* 10V */ #define MAX197_NUM_CH 8 /* 8 Analog Input Channels */ /* Control byte format */ #define MAX197_BIP (1 << 3) /* Bipolarity */ #define MAX197_RNG (1 << 4) /* Full range */ #define MAX197_SCALE 12207 /* Scale coefficient for raw data */ /* List of supported chips */ enum max197_chips { max197, max199 }; /** * struct max197_data - device instance specific data * @pdata: Platform data. * @hwmon_dev: The hwmon device. * @lock: Read/Write mutex. * @limit: Max range value (10V for MAX197, 4V for MAX199). * @scale: Need to scale. * @ctrl_bytes: Channels control byte. */ struct max197_data { struct max197_platform_data *pdata; struct device *hwmon_dev; struct mutex lock; int limit; bool scale; u8 ctrl_bytes[MAX197_NUM_CH]; }; static inline void max197_set_unipolarity(struct max197_data *data, int channel) { data->ctrl_bytes[channel] &= ~MAX197_BIP; } static inline void max197_set_bipolarity(struct max197_data *data, int channel) { data->ctrl_bytes[channel] |= MAX197_BIP; } static inline void max197_set_half_range(struct max197_data *data, int channel) { data->ctrl_bytes[channel] &= ~MAX197_RNG; } static inline void max197_set_full_range(struct max197_data *data, int channel) { data->ctrl_bytes[channel] |= MAX197_RNG; } static inline bool max197_is_bipolar(struct max197_data *data, int channel) { return data->ctrl_bytes[channel] & MAX197_BIP; } static inline bool max197_is_full_range(struct max197_data *data, int channel) { return data->ctrl_bytes[channel] & MAX197_RNG; } /* Function called on read access on in{0,1,2,3,4,5,6,7}_{min,max} */ static ssize_t max197_show_range(struct device *dev, struct device_attribute *devattr, char *buf) { struct max197_data *data = dev_get_drvdata(dev); struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr); int channel = attr->index; bool is_min = attr->nr; int range; if (mutex_lock_interruptible(&data->lock)) return -ERESTARTSYS; range = max197_is_full_range(data, channel) ? data->limit : data->limit / 2; if (is_min) { if (max197_is_bipolar(data, channel)) range = -range; else range = 0; } mutex_unlock(&data->lock); return sprintf(buf, "%d\n", range); } /* Function called on write access on in{0,1,2,3,4,5,6,7}_{min,max} */ static ssize_t max197_store_range(struct device *dev, struct device_attribute *devattr, const char *buf, size_t count) { struct max197_data *data = dev_get_drvdata(dev); struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr); int channel = attr->index; bool is_min = attr->nr; long value; int half = data->limit / 2; int full = data->limit; if (kstrtol(buf, 10, &value)) return -EINVAL; if (is_min) { if (value <= -full) value = -full; else if (value < 0) value = -half; else value = 0; } else { if (value >= full) value = full; else value = half; } if (mutex_lock_interruptible(&data->lock)) return -ERESTARTSYS; if (value == 0) { /* We can deduce only the polarity */ max197_set_unipolarity(data, channel); } else if (value == -half) { max197_set_bipolarity(data, channel); max197_set_half_range(data, channel); } else if (value == -full) { max197_set_bipolarity(data, channel); max197_set_full_range(data, channel); } else if (value == half) { /* We can deduce only the range */ max197_set_half_range(data, channel); } else if (value == full) { /* We can deduce only the range */ max197_set_full_range(data, channel); } mutex_unlock(&data->lock); return count; } /* Function called on read access on in{0,1,2,3,4,5,6,7}_input */ static ssize_t max197_show_input(struct device *dev, struct device_attribute *devattr, char *buf) { struct max197_data *data = dev_get_drvdata(dev); struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); int channel = attr->index; s32 value; int ret; if (mutex_lock_interruptible(&data->lock)) return -ERESTARTSYS; ret = data->pdata->convert(data->ctrl_bytes[channel]); if (ret < 0) { dev_err(dev, "conversion failed\n"); goto unlock; } value = ret; /* * Coefficient to apply on raw value. * See Table 1. Full Scale and Zero Scale in the MAX197 datasheet. */ if (data->scale) { value *= MAX197_SCALE; if (max197_is_full_range(data, channel)) value *= 2; value /= 10000; } ret = sprintf(buf, "%d\n", value); unlock: mutex_unlock(&data->lock); return ret; } static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) { struct platform_device *pdev = to_platform_device(dev); return sprintf(buf, "%s\n", pdev->name); } #define MAX197_SENSOR_DEVICE_ATTR_CH(chan) \ static SENSOR_DEVICE_ATTR(in##chan##_input, S_IRUGO, \ max197_show_input, NULL, chan); \ static SENSOR_DEVICE_ATTR_2(in##chan##_min, S_IRUGO | S_IWUSR, \ max197_show_range, \ max197_store_range, \ true, chan); \ static SENSOR_DEVICE_ATTR_2(in##chan##_max, S_IRUGO | S_IWUSR, \ max197_show_range, \ max197_store_range, \ false, chan) #define MAX197_SENSOR_DEV_ATTR_IN(chan) \ &sensor_dev_attr_in##chan##_input.dev_attr.attr, \ &sensor_dev_attr_in##chan##_max.dev_attr.attr, \ &sensor_dev_attr_in##chan##_min.dev_attr.attr static DEVICE_ATTR_RO(name); MAX197_SENSOR_DEVICE_ATTR_CH(0); MAX197_SENSOR_DEVICE_ATTR_CH(1); MAX197_SENSOR_DEVICE_ATTR_CH(2); MAX197_SENSOR_DEVICE_ATTR_CH(3); MAX197_SENSOR_DEVICE_ATTR_CH(4); MAX197_SENSOR_DEVICE_ATTR_CH(5); MAX197_SENSOR_DEVICE_ATTR_CH(6); MAX197_SENSOR_DEVICE_ATTR_CH(7); static const struct attribute_group max197_sysfs_group = { .attrs = (struct attribute *[]) { &dev_attr_name.attr, MAX197_SENSOR_DEV_ATTR_IN(0), MAX197_SENSOR_DEV_ATTR_IN(1), MAX197_SENSOR_DEV_ATTR_IN(2), MAX197_SENSOR_DEV_ATTR_IN(3), MAX197_SENSOR_DEV_ATTR_IN(4), MAX197_SENSOR_DEV_ATTR_IN(5), MAX197_SENSOR_DEV_ATTR_IN(6), MAX197_SENSOR_DEV_ATTR_IN(7), NULL }, }; static int max197_probe(struct platform_device *pdev) { int ch, ret; struct max197_data *data; struct max197_platform_data *pdata = dev_get_platdata(&pdev->dev); enum max197_chips chip = platform_get_device_id(pdev)->driver_data; if (pdata == NULL) { dev_err(&pdev->dev, "no platform data supplied\n"); return -EINVAL; } if (pdata->convert == NULL) { dev_err(&pdev->dev, "no convert function supplied\n"); return -EINVAL; } data = devm_kzalloc(&pdev->dev, sizeof(struct max197_data), GFP_KERNEL); if (!data) return -ENOMEM; data->pdata = pdata; mutex_init(&data->lock); if (chip == max197) { data->limit = MAX197_LIMIT; data->scale = true; } else { data->limit = MAX199_LIMIT; data->scale = false; } for (ch = 0; ch < MAX197_NUM_CH; ch++) data->ctrl_bytes[ch] = (u8) ch; platform_set_drvdata(pdev, data); ret = sysfs_create_group(&pdev->dev.kobj, &max197_sysfs_group); if (ret) { dev_err(&pdev->dev, "sysfs create group failed\n"); return ret; } data->hwmon_dev = hwmon_device_register(&pdev->dev); if (IS_ERR(data->hwmon_dev)) { ret = PTR_ERR(data->hwmon_dev); dev_err(&pdev->dev, "hwmon device register failed\n"); goto error; } return 0; error: sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group); return ret; } static int max197_remove(struct platform_device *pdev) { struct max197_data *data = platform_get_drvdata(pdev); hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group); return 0; } static const struct platform_device_id max197_device_ids[] = { { "max197", max197 }, { "max199", max199 }, { } }; MODULE_DEVICE_TABLE(platform, max197_device_ids); static struct platform_driver max197_driver = { .driver = { .name = "max197", }, .probe = max197_probe, .remove = max197_remove, .id_table = max197_device_ids, }; module_platform_driver(max197_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Savoir-faire Linux Inc. <kernel@savoirfairelinux.com>"); MODULE_DESCRIPTION("Maxim MAX197 A/D Converter driver");