--- /dev/null
+/*
+ * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
+ * (C) 2007 EADS Astrium
+ *
+ * This driver is based on the lm75 and other lm_sensors/hwmon drivers
+ *
+ * Written by Steve Hardy <shardy@redhat.com>
+ *
+ * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
+ *
+ * For further information, see the Documentation/hwmon/ads7828 file.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_data/ads7828.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+/* The ADS7828 registers */
+#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
+#define ADS7828_CMD_PD1 0x04 /* Internal vref OFF && A/D ON */
+#define ADS7828_CMD_PD3 0x0C /* Internal vref ON && A/D ON */
+#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
+#define ADS7828_EXT_VREF_MV_MIN 50 /* External vref min value 0.05V */
+#define ADS7828_EXT_VREF_MV_MAX 5250 /* External vref max value 5.25V */
+
+/* List of supported devices */
+enum ads7828_chips { ads7828, ads7830 };
+
+/* Client specific data */
+struct ads7828_data {
+ struct regmap *regmap;
+ u8 cmd_byte; /* Command byte without channel bits */
+ unsigned int lsb_resol; /* Resolution of the ADC sample LSB */
+};
+
+/* Command byte C2,C1,C0 - see datasheet */
+static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
+{
+ return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);
+}
+
+/* sysfs callback function */
+static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct ads7828_data *data = dev_get_drvdata(dev);
+ u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);
+ unsigned int regval;
+ int err;
+
+ err = regmap_read(data->regmap, cmd, ®val);
+ if (err < 0)
+ return err;
+
+ return sprintf(buf, "%d\n",
+ DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));
+}
+
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0);
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6);
+static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7);
+
+static struct attribute *ads7828_attrs[] = {
+ &sensor_dev_attr_in0_input.dev_attr.attr,
+ &sensor_dev_attr_in1_input.dev_attr.attr,
+ &sensor_dev_attr_in2_input.dev_attr.attr,
+ &sensor_dev_attr_in3_input.dev_attr.attr,
+ &sensor_dev_attr_in4_input.dev_attr.attr,
+ &sensor_dev_attr_in5_input.dev_attr.attr,
+ &sensor_dev_attr_in6_input.dev_attr.attr,
+ &sensor_dev_attr_in7_input.dev_attr.attr,
+ NULL
+};
+
+ATTRIBUTE_GROUPS(ads7828);
+
+static const struct regmap_config ads2828_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 16,
+};
+
+static const struct regmap_config ads2830_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
+static int ads7828_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct ads7828_platform_data *pdata = dev_get_platdata(dev);
+ struct ads7828_data *data;
+ struct device *hwmon_dev;
+ unsigned int vref_mv = ADS7828_INT_VREF_MV;
+ bool diff_input = false;
+ bool ext_vref = false;
+
+ data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ if (pdata) {
+ diff_input = pdata->diff_input;
+ ext_vref = pdata->ext_vref;
+ if (ext_vref && pdata->vref_mv)
+ vref_mv = pdata->vref_mv;
+ }
+
+ /* Bound Vref with min/max values */
+ vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
+ ADS7828_EXT_VREF_MV_MAX);
+
+ /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
+ if (id->driver_data == ads7828) {
+ data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
+ data->regmap = devm_regmap_init_i2c(client,
+ &ads2828_regmap_config);
+ } else {
+ data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
+ data->regmap = devm_regmap_init_i2c(client,
+ &ads2830_regmap_config);
+ }
+
+ if (IS_ERR(data->regmap))
+ return PTR_ERR(data->regmap);
+
+ data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
+ if (!diff_input)
+ data->cmd_byte |= ADS7828_CMD_SD_SE;
+
+ hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
+ data,
+ ads7828_groups);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ads7828_device_ids[] = {
+ { "ads7828", ads7828 },
+ { "ads7830", ads7830 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
+
+static struct i2c_driver ads7828_driver = {
+ .driver = {
+ .name = "ads7828",
+ },
+
+ .id_table = ads7828_device_ids,
+ .probe = ads7828_probe,
+};
+
+module_i2c_driver(ads7828_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
+MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
Code Review / kvmfornfv.git / blobdiff