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path: root/drivers/power/supply/rx51_battery.c
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Diffstat (limited to 'drivers/power/supply/rx51_battery.c')
-rw-r--r--drivers/power/supply/rx51_battery.c297
1 files changed, 297 insertions, 0 deletions
diff --git a/drivers/power/supply/rx51_battery.c b/drivers/power/supply/rx51_battery.c
new file mode 100644
index 0000000..af9383d
--- /dev/null
+++ b/drivers/power/supply/rx51_battery.c
@@ -0,0 +1,297 @@
+/*
+ * Nokia RX-51 battery driver
+ *
+ * Copyright (C) 2012 Pali Rohár <pali.rohar@gmail.com>
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <linux/module.h>
+#include <linux/param.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+#include <linux/i2c/twl4030-madc.h>
+#include <linux/iio/consumer.h>
+#include <linux/of.h>
+
+struct rx51_device_info {
+ struct device *dev;
+ struct power_supply *bat;
+ struct power_supply_desc bat_desc;
+ struct iio_channel *channel_temp;
+ struct iio_channel *channel_bsi;
+ struct iio_channel *channel_vbat;
+};
+
+/*
+ * Read ADCIN channel value, code copied from maemo kernel
+ */
+static int rx51_battery_read_adc(struct iio_channel *channel)
+{
+ int val, err;
+ err = iio_read_channel_average_raw(channel, &val);
+ if (err < 0)
+ return err;
+ return val;
+}
+
+/*
+ * Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage
+ * This conversion formula was extracted from maemo program bsi-read
+ */
+static int rx51_battery_read_voltage(struct rx51_device_info *di)
+{
+ int voltage = rx51_battery_read_adc(di->channel_vbat);
+
+ if (voltage < 0) {
+ dev_err(di->dev, "Could not read ADC: %d\n", voltage);
+ return voltage;
+ }
+
+ return 1000 * (10000 * voltage / 1705);
+}
+
+/*
+ * Temperature look-up tables
+ * TEMP = (1/(t1 + 1/298) - 273.15)
+ * Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255))
+ * Formula is based on experimental data, RX-51 CAL data, maemo program bme
+ * and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671
+ */
+
+/*
+ * Table1 (temperature for first 25 RAW values)
+ * Usage: TEMP = rx51_temp_table1[RAW]
+ * RAW is between 1 and 24
+ * TEMP is between 201 C and 55 C
+ */
+static u8 rx51_temp_table1[] = {
+ 255, 201, 159, 138, 124, 114, 106, 99, 94, 89, 85, 82, 78, 75,
+ 73, 70, 68, 66, 64, 62, 61, 59, 57, 56, 55
+};
+
+/*
+ * Table2 (lowest RAW value for temperature)
+ * Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first]
+ * TEMP is between 53 C and -32 C
+ * RAW is between 25 and 993
+ */
+#define rx51_temp_table2_first 53
+static u16 rx51_temp_table2[] = {
+ 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39,
+ 40, 41, 43, 44, 46, 48, 49, 51, 53, 55, 57, 59, 61, 64,
+ 66, 69, 71, 74, 77, 80, 83, 86, 90, 94, 97, 101, 106, 110,
+ 115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211,
+ 221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415,
+ 437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885,
+ 937, 993, 1024
+};
+
+/*
+ * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius
+ * Use Temperature look-up tables for conversation
+ */
+static int rx51_battery_read_temperature(struct rx51_device_info *di)
+{
+ int min = 0;
+ int max = ARRAY_SIZE(rx51_temp_table2) - 1;
+ int raw = rx51_battery_read_adc(di->channel_temp);
+
+ if (raw < 0)
+ dev_err(di->dev, "Could not read ADC: %d\n", raw);
+
+ /* Zero and negative values are undefined */
+ if (raw <= 0)
+ return INT_MAX;
+
+ /* ADC channels are 10 bit, higher value are undefined */
+ if (raw >= (1 << 10))
+ return INT_MIN;
+
+ /* First check for temperature in first direct table */
+ if (raw < ARRAY_SIZE(rx51_temp_table1))
+ return rx51_temp_table1[raw] * 10;
+
+ /* Binary search RAW value in second inverse table */
+ while (max - min > 1) {
+ int mid = (max + min) / 2;
+ if (rx51_temp_table2[mid] <= raw)
+ min = mid;
+ else if (rx51_temp_table2[mid] > raw)
+ max = mid;
+ if (rx51_temp_table2[mid] == raw)
+ break;
+ }
+
+ return (rx51_temp_table2_first - min) * 10;
+}
+
+/*
+ * Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah
+ * This conversion formula was extracted from maemo program bsi-read
+ */
+static int rx51_battery_read_capacity(struct rx51_device_info *di)
+{
+ int capacity = rx51_battery_read_adc(di->channel_bsi);
+
+ if (capacity < 0) {
+ dev_err(di->dev, "Could not read ADC: %d\n", capacity);
+ return capacity;
+ }
+
+ return 1280 * (1200 * capacity)/(1024 - capacity);
+}
+
+/*
+ * Return power_supply property
+ */
+static int rx51_battery_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct rx51_device_info *di = power_supply_get_drvdata(psy);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_TECHNOLOGY:
+ val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
+ break;
+ case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+ val->intval = 4200000;
+ break;
+ case POWER_SUPPLY_PROP_PRESENT:
+ val->intval = rx51_battery_read_voltage(di) ? 1 : 0;
+ break;
+ case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+ val->intval = rx51_battery_read_voltage(di);
+ break;
+ case POWER_SUPPLY_PROP_TEMP:
+ val->intval = rx51_battery_read_temperature(di);
+ break;
+ case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+ val->intval = rx51_battery_read_capacity(di);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (val->intval == INT_MAX || val->intval == INT_MIN)
+ return -EINVAL;
+
+ return 0;
+}
+
+static enum power_supply_property rx51_battery_props[] = {
+ POWER_SUPPLY_PROP_TECHNOLOGY,
+ POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
+ POWER_SUPPLY_PROP_PRESENT,
+ POWER_SUPPLY_PROP_VOLTAGE_NOW,
+ POWER_SUPPLY_PROP_TEMP,
+ POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+};
+
+static int rx51_battery_probe(struct platform_device *pdev)
+{
+ struct power_supply_config psy_cfg = {};
+ struct rx51_device_info *di;
+ int ret;
+
+ di = devm_kzalloc(&pdev->dev, sizeof(*di), GFP_KERNEL);
+ if (!di)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, di);
+
+ di->dev = &pdev->dev;
+ di->bat_desc.name = "rx51-battery";
+ di->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
+ di->bat_desc.properties = rx51_battery_props;
+ di->bat_desc.num_properties = ARRAY_SIZE(rx51_battery_props);
+ di->bat_desc.get_property = rx51_battery_get_property;
+
+ psy_cfg.drv_data = di;
+
+ di->channel_temp = iio_channel_get(di->dev, "temp");
+ if (IS_ERR(di->channel_temp)) {
+ ret = PTR_ERR(di->channel_temp);
+ goto error;
+ }
+
+ di->channel_bsi = iio_channel_get(di->dev, "bsi");
+ if (IS_ERR(di->channel_bsi)) {
+ ret = PTR_ERR(di->channel_bsi);
+ goto error_channel_temp;
+ }
+
+ di->channel_vbat = iio_channel_get(di->dev, "vbat");
+ if (IS_ERR(di->channel_vbat)) {
+ ret = PTR_ERR(di->channel_vbat);
+ goto error_channel_bsi;
+ }
+
+ di->bat = power_supply_register(di->dev, &di->bat_desc, &psy_cfg);
+ if (IS_ERR(di->bat)) {
+ ret = PTR_ERR(di->bat);
+ goto error_channel_vbat;
+ }
+
+ return 0;
+
+error_channel_vbat:
+ iio_channel_release(di->channel_vbat);
+error_channel_bsi:
+ iio_channel_release(di->channel_bsi);
+error_channel_temp:
+ iio_channel_release(di->channel_temp);
+error:
+
+ return ret;
+}
+
+static int rx51_battery_remove(struct platform_device *pdev)
+{
+ struct rx51_device_info *di = platform_get_drvdata(pdev);
+
+ power_supply_unregister(di->bat);
+
+ iio_channel_release(di->channel_vbat);
+ iio_channel_release(di->channel_bsi);
+ iio_channel_release(di->channel_temp);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id n900_battery_of_match[] = {
+ {.compatible = "nokia,n900-battery", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, n900_battery_of_match);
+#endif
+
+static struct platform_driver rx51_battery_driver = {
+ .probe = rx51_battery_probe,
+ .remove = rx51_battery_remove,
+ .driver = {
+ .name = "rx51-battery",
+ .of_match_table = of_match_ptr(n900_battery_of_match),
+ },
+};
+module_platform_driver(rx51_battery_driver);
+
+MODULE_ALIAS("platform:rx51-battery");
+MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
+MODULE_DESCRIPTION("Nokia RX-51 battery driver");
+MODULE_LICENSE("GPL");
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