diff options
Diffstat (limited to 'drivers/hwmon/s3c-hwmon.c')
| -rw-r--r-- | drivers/hwmon/s3c-hwmon.c | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/drivers/hwmon/s3c-hwmon.c b/drivers/hwmon/s3c-hwmon.c new file mode 100644 index 000000000..70ae665db --- /dev/null +++ b/drivers/hwmon/s3c-hwmon.c @@ -0,0 +1,379 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* linux/drivers/hwmon/s3c-hwmon.c + * + * Copyright (C) 2005, 2008, 2009 Simtec Electronics + * http://armlinux.simtec.co.uk/ + * Ben Dooks <ben@simtec.co.uk> + * + * S3C24XX/S3C64XX ADC hwmon support +*/ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/init.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> + +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> + +#include <linux/soc/samsung/s3c-adc.h> +#include <linux/platform_data/hwmon-s3c.h> + +struct s3c_hwmon_attr { + struct sensor_device_attribute in; + struct sensor_device_attribute label; + char in_name[12]; + char label_name[12]; +}; + +/** + * struct s3c_hwmon - ADC hwmon client information + * @lock: Access lock to serialise the conversions. + * @client: The client we registered with the S3C ADC core. + * @hwmon_dev: The hwmon device we created. + * @attr: The holders for the channel attributes. +*/ +struct s3c_hwmon { + struct mutex lock; + struct s3c_adc_client *client; + struct device *hwmon_dev; + + struct s3c_hwmon_attr attrs[8]; +}; + +/** + * s3c_hwmon_read_ch - read a value from a given adc channel. + * @dev: The device. + * @hwmon: Our state. + * @channel: The channel we're reading from. + * + * Read a value from the @channel with the proper locking and sleep until + * either the read completes or we timeout awaiting the ADC core to get + * back to us. + */ +static int s3c_hwmon_read_ch(struct device *dev, + struct s3c_hwmon *hwmon, int channel) +{ + int ret; + + ret = mutex_lock_interruptible(&hwmon->lock); + if (ret < 0) + return ret; + + dev_dbg(dev, "reading channel %d\n", channel); + + ret = s3c_adc_read(hwmon->client, channel); + mutex_unlock(&hwmon->lock); + + return ret; +} + +#ifdef CONFIG_SENSORS_S3C_RAW +/** + * s3c_hwmon_show_raw - show a conversion from the raw channel number. + * @dev: The device that the attribute belongs to. + * @attr: The attribute being read. + * @buf: The result buffer. + * + * This show deals with the raw attribute, registered for each possible + * ADC channel. This does a conversion and returns the raw (un-scaled) + * value returned from the hardware. + */ +static ssize_t s3c_hwmon_show_raw(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct s3c_hwmon *adc = dev_get_drvdata(dev); + struct sensor_device_attribute *sa = to_sensor_dev_attr(attr); + int ret; + + ret = s3c_hwmon_read_ch(dev, adc, sa->index); + + return (ret < 0) ? ret : snprintf(buf, PAGE_SIZE, "%d\n", ret); +} + +static SENSOR_DEVICE_ATTR(adc0_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 0); +static SENSOR_DEVICE_ATTR(adc1_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 1); +static SENSOR_DEVICE_ATTR(adc2_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 2); +static SENSOR_DEVICE_ATTR(adc3_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 3); +static SENSOR_DEVICE_ATTR(adc4_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 4); +static SENSOR_DEVICE_ATTR(adc5_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 5); +static SENSOR_DEVICE_ATTR(adc6_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 6); +static SENSOR_DEVICE_ATTR(adc7_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 7); + +static struct attribute *s3c_hwmon_attrs[9] = { + &sensor_dev_attr_adc0_raw.dev_attr.attr, + &sensor_dev_attr_adc1_raw.dev_attr.attr, + &sensor_dev_attr_adc2_raw.dev_attr.attr, + &sensor_dev_attr_adc3_raw.dev_attr.attr, + &sensor_dev_attr_adc4_raw.dev_attr.attr, + &sensor_dev_attr_adc5_raw.dev_attr.attr, + &sensor_dev_attr_adc6_raw.dev_attr.attr, + &sensor_dev_attr_adc7_raw.dev_attr.attr, + NULL, +}; + +static struct attribute_group s3c_hwmon_attrgroup = { + .attrs = s3c_hwmon_attrs, +}; + +static inline int s3c_hwmon_add_raw(struct device *dev) +{ + return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup); +} + +static inline void s3c_hwmon_remove_raw(struct device *dev) +{ + sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup); +} + +#else + +static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; } +static inline void s3c_hwmon_remove_raw(struct device *dev) { } + +#endif /* CONFIG_SENSORS_S3C_RAW */ + +/** + * s3c_hwmon_ch_show - show value of a given channel + * @dev: The device that the attribute belongs to. + * @attr: The attribute being read. + * @buf: The result buffer. + * + * Read a value from the ADC and scale it before returning it to the + * caller. The scale factor is gained from the channel configuration + * passed via the platform data when the device was registered. + */ +static ssize_t s3c_hwmon_ch_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr); + struct s3c_hwmon *hwmon = dev_get_drvdata(dev); + struct s3c_hwmon_pdata *pdata = dev_get_platdata(dev); + struct s3c_hwmon_chcfg *cfg; + int ret; + + cfg = pdata->in[sen_attr->index]; + + ret = s3c_hwmon_read_ch(dev, hwmon, sen_attr->index); + if (ret < 0) + return ret; + + ret *= cfg->mult; + ret = DIV_ROUND_CLOSEST(ret, cfg->div); + + return sysfs_emit(buf, "%d\n", ret); +} + +/** + * s3c_hwmon_label_show - show label name of the given channel. + * @dev: The device that the attribute belongs to. + * @attr: The attribute being read. + * @buf: The result buffer. + * + * Return the label name of a given channel + */ +static ssize_t s3c_hwmon_label_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr); + struct s3c_hwmon_pdata *pdata = dev_get_platdata(dev); + struct s3c_hwmon_chcfg *cfg; + + cfg = pdata->in[sen_attr->index]; + + return sysfs_emit(buf, "%s\n", cfg->name); +} + +/** + * s3c_hwmon_create_attr - create hwmon attribute for given channel. + * @dev: The device to create the attribute on. + * @cfg: The channel configuration passed from the platform data. + * @channel: The ADC channel number to process. + * + * Create the scaled attribute for use with hwmon from the specified + * platform data in @pdata. The sysfs entry is handled by the routine + * s3c_hwmon_ch_show(). + * + * The attribute name is taken from the configuration data if present + * otherwise the name is taken by concatenating in_ with the channel + * number. + */ +static int s3c_hwmon_create_attr(struct device *dev, + struct s3c_hwmon_chcfg *cfg, + struct s3c_hwmon_attr *attrs, + int channel) +{ + struct sensor_device_attribute *attr; + int ret; + + snprintf(attrs->in_name, sizeof(attrs->in_name), "in%d_input", channel); + + attr = &attrs->in; + attr->index = channel; + sysfs_attr_init(&attr->dev_attr.attr); + attr->dev_attr.attr.name = attrs->in_name; + attr->dev_attr.attr.mode = S_IRUGO; + attr->dev_attr.show = s3c_hwmon_ch_show; + + ret = device_create_file(dev, &attr->dev_attr); + if (ret < 0) { + dev_err(dev, "failed to create input attribute\n"); + return ret; + } + + /* if this has a name, add a label */ + if (cfg->name) { + snprintf(attrs->label_name, sizeof(attrs->label_name), + "in%d_label", channel); + + attr = &attrs->label; + attr->index = channel; + sysfs_attr_init(&attr->dev_attr.attr); + attr->dev_attr.attr.name = attrs->label_name; + attr->dev_attr.attr.mode = S_IRUGO; + attr->dev_attr.show = s3c_hwmon_label_show; + + ret = device_create_file(dev, &attr->dev_attr); + if (ret < 0) { + device_remove_file(dev, &attrs->in.dev_attr); + dev_err(dev, "failed to create label attribute\n"); + } + } + + return ret; +} + +static void s3c_hwmon_remove_attr(struct device *dev, + struct s3c_hwmon_attr *attrs) +{ + device_remove_file(dev, &attrs->in.dev_attr); + device_remove_file(dev, &attrs->label.dev_attr); +} + +/** + * s3c_hwmon_probe - device probe entry. + * @dev: The device being probed. +*/ +static int s3c_hwmon_probe(struct platform_device *dev) +{ + struct s3c_hwmon_pdata *pdata = dev_get_platdata(&dev->dev); + struct s3c_hwmon *hwmon; + int ret = 0; + int i; + + if (!pdata) { + dev_err(&dev->dev, "no platform data supplied\n"); + return -EINVAL; + } + + hwmon = devm_kzalloc(&dev->dev, sizeof(struct s3c_hwmon), GFP_KERNEL); + if (hwmon == NULL) + return -ENOMEM; + + platform_set_drvdata(dev, hwmon); + + mutex_init(&hwmon->lock); + + /* Register with the core ADC driver. */ + + hwmon->client = s3c_adc_register(dev, NULL, NULL, 0); + if (IS_ERR(hwmon->client)) { + dev_err(&dev->dev, "cannot register adc\n"); + return PTR_ERR(hwmon->client); + } + + /* add attributes for our adc devices. */ + + ret = s3c_hwmon_add_raw(&dev->dev); + if (ret) + goto err_registered; + + /* register with the hwmon core */ + + hwmon->hwmon_dev = hwmon_device_register(&dev->dev); + if (IS_ERR(hwmon->hwmon_dev)) { + dev_err(&dev->dev, "error registering with hwmon\n"); + ret = PTR_ERR(hwmon->hwmon_dev); + goto err_raw_attribute; + } + + for (i = 0; i < ARRAY_SIZE(pdata->in); i++) { + struct s3c_hwmon_chcfg *cfg = pdata->in[i]; + + if (!cfg) + continue; + + if (cfg->mult >= 0x10000) + dev_warn(&dev->dev, + "channel %d multiplier too large\n", + i); + + if (cfg->div == 0) { + dev_err(&dev->dev, "channel %d divider zero\n", i); + continue; + } + + ret = s3c_hwmon_create_attr(&dev->dev, pdata->in[i], + &hwmon->attrs[i], i); + if (ret) { + dev_err(&dev->dev, + "error creating channel %d\n", i); + + for (i--; i >= 0; i--) + s3c_hwmon_remove_attr(&dev->dev, + &hwmon->attrs[i]); + + goto err_hwmon_register; + } + } + + return 0; + + err_hwmon_register: + hwmon_device_unregister(hwmon->hwmon_dev); + + err_raw_attribute: + s3c_hwmon_remove_raw(&dev->dev); + + err_registered: + s3c_adc_release(hwmon->client); + + return ret; +} + +static int s3c_hwmon_remove(struct platform_device *dev) +{ + struct s3c_hwmon *hwmon = platform_get_drvdata(dev); + int i; + + s3c_hwmon_remove_raw(&dev->dev); + + for (i = 0; i < ARRAY_SIZE(hwmon->attrs); i++) + s3c_hwmon_remove_attr(&dev->dev, &hwmon->attrs[i]); + + hwmon_device_unregister(hwmon->hwmon_dev); + s3c_adc_release(hwmon->client); + + return 0; +} + +static struct platform_driver s3c_hwmon_driver = { + .driver = { + .name = "s3c-hwmon", + }, + .probe = s3c_hwmon_probe, + .remove = s3c_hwmon_remove, +}; + +module_platform_driver(s3c_hwmon_driver); + +MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); +MODULE_DESCRIPTION("S3C ADC HWMon driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:s3c-hwmon"); |