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The isl12022 has built-in temperature compensation effective over the range -40C to +85C. It exposes the average of the last two temperature measurements as a 10-bit value in half-Kelvins. Make this available via the hwmon framework. Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Link: https://lore.kernel.org/r/20221104110225.2219761-1-linux@rasmusvillemoes.dk Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
299 lines
7.4 KiB
C
299 lines
7.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* An I2C driver for the Intersil ISL 12022
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*
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* Author: Roman Fietze <roman.fietze@telemotive.de>
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*
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* Based on the Philips PCF8563 RTC
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* by Alessandro Zummo <a.zummo@towertech.it>.
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*/
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#include <linux/i2c.h>
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#include <linux/bcd.h>
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#include <linux/rtc.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/regmap.h>
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#include <linux/hwmon.h>
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/* ISL register offsets */
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#define ISL12022_REG_SC 0x00
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#define ISL12022_REG_MN 0x01
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#define ISL12022_REG_HR 0x02
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#define ISL12022_REG_DT 0x03
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#define ISL12022_REG_MO 0x04
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#define ISL12022_REG_YR 0x05
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#define ISL12022_REG_DW 0x06
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#define ISL12022_REG_SR 0x07
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#define ISL12022_REG_INT 0x08
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#define ISL12022_REG_BETA 0x0d
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#define ISL12022_REG_TEMP_L 0x28
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/* ISL register bits */
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#define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
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#define ISL12022_SR_LBAT85 (1 << 2)
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#define ISL12022_SR_LBAT75 (1 << 1)
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#define ISL12022_INT_WRTC (1 << 6)
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#define ISL12022_BETA_TSE (1 << 7)
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static struct i2c_driver isl12022_driver;
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struct isl12022 {
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struct rtc_device *rtc;
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struct regmap *regmap;
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};
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static umode_t isl12022_hwmon_is_visible(const void *data,
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enum hwmon_sensor_types type,
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u32 attr, int channel)
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{
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if (type == hwmon_temp && attr == hwmon_temp_input)
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return 0444;
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return 0;
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}
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/*
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* A user-initiated temperature conversion is not started by this function,
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* so the temperature is updated once every ~60 seconds.
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*/
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static int isl12022_hwmon_read_temp(struct device *dev, long *mC)
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{
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struct isl12022 *isl12022 = dev_get_drvdata(dev);
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struct regmap *regmap = isl12022->regmap;
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u8 temp_buf[2];
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int temp, ret;
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ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L,
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temp_buf, sizeof(temp_buf));
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if (ret)
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return ret;
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/*
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* Temperature is represented as a 10-bit number, unit half-Kelvins.
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*/
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temp = (temp_buf[1] << 8) | temp_buf[0];
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temp *= 500;
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temp -= 273000;
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*mC = temp;
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return 0;
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}
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static int isl12022_hwmon_read(struct device *dev,
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enum hwmon_sensor_types type,
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u32 attr, int channel, long *val)
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{
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if (type == hwmon_temp && attr == hwmon_temp_input)
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return isl12022_hwmon_read_temp(dev, val);
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return -EOPNOTSUPP;
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}
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static const struct hwmon_channel_info *isl12022_hwmon_info[] = {
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HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
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NULL
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};
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static const struct hwmon_ops isl12022_hwmon_ops = {
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.is_visible = isl12022_hwmon_is_visible,
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.read = isl12022_hwmon_read,
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};
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static const struct hwmon_chip_info isl12022_hwmon_chip_info = {
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.ops = &isl12022_hwmon_ops,
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.info = isl12022_hwmon_info,
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};
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static void isl12022_hwmon_register(struct device *dev)
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{
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struct isl12022 *isl12022;
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struct device *hwmon;
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int ret;
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if (!IS_REACHABLE(CONFIG_HWMON))
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return;
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isl12022 = dev_get_drvdata(dev);
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ret = regmap_update_bits(isl12022->regmap, ISL12022_REG_BETA,
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ISL12022_BETA_TSE, ISL12022_BETA_TSE);
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if (ret) {
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dev_warn(dev, "unable to enable temperature sensor\n");
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return;
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}
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hwmon = devm_hwmon_device_register_with_info(dev, "isl12022", isl12022,
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&isl12022_hwmon_chip_info,
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NULL);
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if (IS_ERR(hwmon))
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dev_warn(dev, "unable to register hwmon device: %pe\n", hwmon);
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}
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/*
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* In the routines that deal directly with the isl12022 hardware, we use
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* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
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*/
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static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct isl12022 *isl12022 = dev_get_drvdata(dev);
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struct regmap *regmap = isl12022->regmap;
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uint8_t buf[ISL12022_REG_INT + 1];
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int ret;
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ret = regmap_bulk_read(regmap, ISL12022_REG_SC, buf, sizeof(buf));
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if (ret)
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return ret;
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if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
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dev_warn(dev,
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"voltage dropped below %u%%, "
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"date and time is not reliable.\n",
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buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
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}
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dev_dbg(dev,
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"%s: raw data is sec=%02x, min=%02x, hr=%02x, "
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"mday=%02x, mon=%02x, year=%02x, wday=%02x, "
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"sr=%02x, int=%02x",
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__func__,
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buf[ISL12022_REG_SC],
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buf[ISL12022_REG_MN],
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buf[ISL12022_REG_HR],
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buf[ISL12022_REG_DT],
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buf[ISL12022_REG_MO],
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buf[ISL12022_REG_YR],
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buf[ISL12022_REG_DW],
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buf[ISL12022_REG_SR],
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buf[ISL12022_REG_INT]);
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tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
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tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
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tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
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tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
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tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
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tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
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tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
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dev_dbg(dev, "%s: %ptR\n", __func__, tm);
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return 0;
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}
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static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct isl12022 *isl12022 = dev_get_drvdata(dev);
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struct regmap *regmap = isl12022->regmap;
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int ret;
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uint8_t buf[ISL12022_REG_DW + 1];
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dev_dbg(dev, "%s: %ptR\n", __func__, tm);
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/* Ensure the write enable bit is set. */
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ret = regmap_update_bits(regmap, ISL12022_REG_INT,
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ISL12022_INT_WRTC, ISL12022_INT_WRTC);
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if (ret)
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return ret;
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/* hours, minutes and seconds */
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buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
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buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
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buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
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buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
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/* month, 1 - 12 */
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buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
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/* year and century */
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buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
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buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
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return regmap_bulk_write(isl12022->regmap, ISL12022_REG_SC,
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buf, sizeof(buf));
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}
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static const struct rtc_class_ops isl12022_rtc_ops = {
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.read_time = isl12022_rtc_read_time,
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.set_time = isl12022_rtc_set_time,
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};
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static const struct regmap_config regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.use_single_write = true,
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};
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static int isl12022_probe(struct i2c_client *client)
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{
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struct isl12022 *isl12022;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -ENODEV;
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isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022),
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GFP_KERNEL);
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if (!isl12022)
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return -ENOMEM;
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dev_set_drvdata(&client->dev, isl12022);
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isl12022->regmap = devm_regmap_init_i2c(client, ®map_config);
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if (IS_ERR(isl12022->regmap)) {
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dev_err(&client->dev, "regmap allocation failed\n");
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return PTR_ERR(isl12022->regmap);
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}
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isl12022_hwmon_register(&client->dev);
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isl12022->rtc = devm_rtc_allocate_device(&client->dev);
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if (IS_ERR(isl12022->rtc))
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return PTR_ERR(isl12022->rtc);
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isl12022->rtc->ops = &isl12022_rtc_ops;
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isl12022->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
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isl12022->rtc->range_max = RTC_TIMESTAMP_END_2099;
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return devm_rtc_register_device(isl12022->rtc);
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}
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#ifdef CONFIG_OF
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static const struct of_device_id isl12022_dt_match[] = {
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{ .compatible = "isl,isl12022" }, /* for backward compat., don't use */
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{ .compatible = "isil,isl12022" },
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{ },
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};
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MODULE_DEVICE_TABLE(of, isl12022_dt_match);
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#endif
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static const struct i2c_device_id isl12022_id[] = {
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{ "isl12022", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, isl12022_id);
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static struct i2c_driver isl12022_driver = {
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.driver = {
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.name = "rtc-isl12022",
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#ifdef CONFIG_OF
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.of_match_table = of_match_ptr(isl12022_dt_match),
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#endif
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},
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.probe_new = isl12022_probe,
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.id_table = isl12022_id,
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};
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module_i2c_driver(isl12022_driver);
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MODULE_AUTHOR("roman.fietze@telemotive.de");
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MODULE_DESCRIPTION("ISL 12022 RTC driver");
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MODULE_LICENSE("GPL");
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