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344 lines
8.5 KiB
344 lines
8.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Maxim MAX197 A/D Converter driver |
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* |
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* Copyright (c) 2012 Savoir-faire Linux Inc. |
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* Vivien Didelot <[email protected]> |
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* |
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* For further information, see the Documentation/hwmon/max197.rst file. |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/init.h> |
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#include <linux/err.h> |
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#include <linux/slab.h> |
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#include <linux/mutex.h> |
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#include <linux/device.h> |
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#include <linux/sysfs.h> |
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#include <linux/hwmon.h> |
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#include <linux/hwmon-sysfs.h> |
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#include <linux/platform_device.h> |
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#include <linux/platform_data/max197.h> |
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#define MAX199_LIMIT 4000 /* 4V */ |
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#define MAX197_LIMIT 10000 /* 10V */ |
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#define MAX197_NUM_CH 8 /* 8 Analog Input Channels */ |
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/* Control byte format */ |
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#define MAX197_BIP (1 << 3) /* Bipolarity */ |
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#define MAX197_RNG (1 << 4) /* Full range */ |
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#define MAX197_SCALE 12207 /* Scale coefficient for raw data */ |
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/* List of supported chips */ |
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enum max197_chips { max197, max199 }; |
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/** |
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* struct max197_data - device instance specific data |
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* @pdata: Platform data. |
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* @hwmon_dev: The hwmon device. |
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* @lock: Read/Write mutex. |
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* @limit: Max range value (10V for MAX197, 4V for MAX199). |
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* @scale: Need to scale. |
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* @ctrl_bytes: Channels control byte. |
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*/ |
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struct max197_data { |
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struct max197_platform_data *pdata; |
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struct device *hwmon_dev; |
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struct mutex lock; |
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int limit; |
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bool scale; |
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u8 ctrl_bytes[MAX197_NUM_CH]; |
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}; |
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static inline void max197_set_unipolarity(struct max197_data *data, int channel) |
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{ |
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data->ctrl_bytes[channel] &= ~MAX197_BIP; |
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} |
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static inline void max197_set_bipolarity(struct max197_data *data, int channel) |
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{ |
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data->ctrl_bytes[channel] |= MAX197_BIP; |
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} |
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static inline void max197_set_half_range(struct max197_data *data, int channel) |
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{ |
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data->ctrl_bytes[channel] &= ~MAX197_RNG; |
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} |
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static inline void max197_set_full_range(struct max197_data *data, int channel) |
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{ |
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data->ctrl_bytes[channel] |= MAX197_RNG; |
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} |
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static inline bool max197_is_bipolar(struct max197_data *data, int channel) |
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{ |
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return data->ctrl_bytes[channel] & MAX197_BIP; |
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} |
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static inline bool max197_is_full_range(struct max197_data *data, int channel) |
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{ |
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return data->ctrl_bytes[channel] & MAX197_RNG; |
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} |
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/* Function called on read access on in{0,1,2,3,4,5,6,7}_{min,max} */ |
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static ssize_t max197_show_range(struct device *dev, |
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struct device_attribute *devattr, char *buf) |
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{ |
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struct max197_data *data = dev_get_drvdata(dev); |
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struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr); |
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int channel = attr->index; |
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bool is_min = attr->nr; |
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int range; |
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if (mutex_lock_interruptible(&data->lock)) |
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return -ERESTARTSYS; |
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range = max197_is_full_range(data, channel) ? |
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data->limit : data->limit / 2; |
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if (is_min) { |
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if (max197_is_bipolar(data, channel)) |
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range = -range; |
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else |
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range = 0; |
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} |
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mutex_unlock(&data->lock); |
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return sprintf(buf, "%d\n", range); |
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} |
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/* Function called on write access on in{0,1,2,3,4,5,6,7}_{min,max} */ |
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static ssize_t max197_store_range(struct device *dev, |
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struct device_attribute *devattr, |
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const char *buf, size_t count) |
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{ |
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struct max197_data *data = dev_get_drvdata(dev); |
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struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr); |
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int channel = attr->index; |
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bool is_min = attr->nr; |
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long value; |
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int half = data->limit / 2; |
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int full = data->limit; |
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if (kstrtol(buf, 10, &value)) |
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return -EINVAL; |
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if (is_min) { |
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if (value <= -full) |
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value = -full; |
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else if (value < 0) |
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value = -half; |
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else |
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value = 0; |
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} else { |
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if (value >= full) |
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value = full; |
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else |
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value = half; |
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} |
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if (mutex_lock_interruptible(&data->lock)) |
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return -ERESTARTSYS; |
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if (value == 0) { |
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/* We can deduce only the polarity */ |
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max197_set_unipolarity(data, channel); |
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} else if (value == -half) { |
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max197_set_bipolarity(data, channel); |
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max197_set_half_range(data, channel); |
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} else if (value == -full) { |
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max197_set_bipolarity(data, channel); |
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max197_set_full_range(data, channel); |
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} else if (value == half) { |
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/* We can deduce only the range */ |
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max197_set_half_range(data, channel); |
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} else if (value == full) { |
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/* We can deduce only the range */ |
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max197_set_full_range(data, channel); |
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} |
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mutex_unlock(&data->lock); |
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return count; |
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} |
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/* Function called on read access on in{0,1,2,3,4,5,6,7}_input */ |
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static ssize_t max197_show_input(struct device *dev, |
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struct device_attribute *devattr, |
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char *buf) |
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{ |
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struct max197_data *data = dev_get_drvdata(dev); |
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struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); |
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int channel = attr->index; |
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s32 value; |
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int ret; |
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if (mutex_lock_interruptible(&data->lock)) |
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return -ERESTARTSYS; |
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ret = data->pdata->convert(data->ctrl_bytes[channel]); |
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if (ret < 0) { |
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dev_err(dev, "conversion failed\n"); |
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goto unlock; |
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} |
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value = ret; |
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/* |
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* Coefficient to apply on raw value. |
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* See Table 1. Full Scale and Zero Scale in the MAX197 datasheet. |
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*/ |
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if (data->scale) { |
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value *= MAX197_SCALE; |
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if (max197_is_full_range(data, channel)) |
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value *= 2; |
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value /= 10000; |
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} |
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ret = sprintf(buf, "%d\n", value); |
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unlock: |
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mutex_unlock(&data->lock); |
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return ret; |
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} |
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static ssize_t name_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct platform_device *pdev = to_platform_device(dev); |
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return sprintf(buf, "%s\n", pdev->name); |
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} |
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#define MAX197_SENSOR_DEVICE_ATTR_CH(chan) \ |
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static SENSOR_DEVICE_ATTR(in##chan##_input, S_IRUGO, \ |
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max197_show_input, NULL, chan); \ |
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static SENSOR_DEVICE_ATTR_2(in##chan##_min, S_IRUGO | S_IWUSR, \ |
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max197_show_range, \ |
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max197_store_range, \ |
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true, chan); \ |
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static SENSOR_DEVICE_ATTR_2(in##chan##_max, S_IRUGO | S_IWUSR, \ |
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max197_show_range, \ |
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max197_store_range, \ |
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false, chan) |
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#define MAX197_SENSOR_DEV_ATTR_IN(chan) \ |
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&sensor_dev_attr_in##chan##_input.dev_attr.attr, \ |
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&sensor_dev_attr_in##chan##_max.dev_attr.attr, \ |
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&sensor_dev_attr_in##chan##_min.dev_attr.attr |
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static DEVICE_ATTR_RO(name); |
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MAX197_SENSOR_DEVICE_ATTR_CH(0); |
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MAX197_SENSOR_DEVICE_ATTR_CH(1); |
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MAX197_SENSOR_DEVICE_ATTR_CH(2); |
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MAX197_SENSOR_DEVICE_ATTR_CH(3); |
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MAX197_SENSOR_DEVICE_ATTR_CH(4); |
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MAX197_SENSOR_DEVICE_ATTR_CH(5); |
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MAX197_SENSOR_DEVICE_ATTR_CH(6); |
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MAX197_SENSOR_DEVICE_ATTR_CH(7); |
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static const struct attribute_group max197_sysfs_group = { |
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.attrs = (struct attribute *[]) { |
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&dev_attr_name.attr, |
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MAX197_SENSOR_DEV_ATTR_IN(0), |
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MAX197_SENSOR_DEV_ATTR_IN(1), |
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MAX197_SENSOR_DEV_ATTR_IN(2), |
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MAX197_SENSOR_DEV_ATTR_IN(3), |
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MAX197_SENSOR_DEV_ATTR_IN(4), |
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MAX197_SENSOR_DEV_ATTR_IN(5), |
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MAX197_SENSOR_DEV_ATTR_IN(6), |
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MAX197_SENSOR_DEV_ATTR_IN(7), |
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NULL |
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}, |
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}; |
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static int max197_probe(struct platform_device *pdev) |
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{ |
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int ch, ret; |
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struct max197_data *data; |
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struct max197_platform_data *pdata = dev_get_platdata(&pdev->dev); |
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enum max197_chips chip = platform_get_device_id(pdev)->driver_data; |
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if (pdata == NULL) { |
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dev_err(&pdev->dev, "no platform data supplied\n"); |
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return -EINVAL; |
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} |
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if (pdata->convert == NULL) { |
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dev_err(&pdev->dev, "no convert function supplied\n"); |
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return -EINVAL; |
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} |
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data = devm_kzalloc(&pdev->dev, sizeof(struct max197_data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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data->pdata = pdata; |
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mutex_init(&data->lock); |
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if (chip == max197) { |
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data->limit = MAX197_LIMIT; |
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data->scale = true; |
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} else { |
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data->limit = MAX199_LIMIT; |
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data->scale = false; |
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} |
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for (ch = 0; ch < MAX197_NUM_CH; ch++) |
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data->ctrl_bytes[ch] = (u8) ch; |
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platform_set_drvdata(pdev, data); |
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ret = sysfs_create_group(&pdev->dev.kobj, &max197_sysfs_group); |
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if (ret) { |
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dev_err(&pdev->dev, "sysfs create group failed\n"); |
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return ret; |
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} |
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data->hwmon_dev = hwmon_device_register(&pdev->dev); |
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if (IS_ERR(data->hwmon_dev)) { |
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ret = PTR_ERR(data->hwmon_dev); |
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dev_err(&pdev->dev, "hwmon device register failed\n"); |
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goto error; |
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} |
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return 0; |
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error: |
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sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group); |
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return ret; |
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} |
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static int max197_remove(struct platform_device *pdev) |
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{ |
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struct max197_data *data = platform_get_drvdata(pdev); |
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hwmon_device_unregister(data->hwmon_dev); |
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sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group); |
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return 0; |
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} |
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static const struct platform_device_id max197_device_ids[] = { |
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{ "max197", max197 }, |
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{ "max199", max199 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(platform, max197_device_ids); |
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static struct platform_driver max197_driver = { |
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.driver = { |
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.name = "max197", |
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}, |
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.probe = max197_probe, |
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.remove = max197_remove, |
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.id_table = max197_device_ids, |
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}; |
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module_platform_driver(max197_driver); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Savoir-faire Linux Inc. <[email protected]>"); |
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MODULE_DESCRIPTION("Maxim MAX197 A/D Converter driver");
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