diff options
Diffstat (limited to 'drivers/rtc/rtc-isl12022.c')
| -rw-r--r-- | drivers/rtc/rtc-isl12022.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-isl12022.c b/drivers/rtc/rtc-isl12022.c new file mode 100644 index 000000000..ca677c426 --- /dev/null +++ b/drivers/rtc/rtc-isl12022.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * An I2C driver for the Intersil ISL 12022 + * + * Author: Roman Fietze <roman.fietze@telemotive.de> + * + * Based on the Philips PCF8563 RTC + * by Alessandro Zummo <a.zummo@towertech.it>. + */ + +#include <linux/i2c.h> +#include <linux/bcd.h> +#include <linux/rtc.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/err.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/regmap.h> + +/* ISL register offsets */ +#define ISL12022_REG_SC 0x00 +#define ISL12022_REG_MN 0x01 +#define ISL12022_REG_HR 0x02 +#define ISL12022_REG_DT 0x03 +#define ISL12022_REG_MO 0x04 +#define ISL12022_REG_YR 0x05 +#define ISL12022_REG_DW 0x06 + +#define ISL12022_REG_SR 0x07 +#define ISL12022_REG_INT 0x08 + +/* ISL register bits */ +#define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */ + +#define ISL12022_SR_LBAT85 (1 << 2) +#define ISL12022_SR_LBAT75 (1 << 1) + +#define ISL12022_INT_WRTC (1 << 6) + + +static struct i2c_driver isl12022_driver; + +struct isl12022 { + struct rtc_device *rtc; + struct regmap *regmap; +}; + +/* + * In the routines that deal directly with the isl12022 hardware, we use + * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. + */ +static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct isl12022 *isl12022 = dev_get_drvdata(dev); + struct regmap *regmap = isl12022->regmap; + uint8_t buf[ISL12022_REG_INT + 1]; + int ret; + + ret = regmap_bulk_read(regmap, ISL12022_REG_SC, buf, sizeof(buf)); + if (ret) + return ret; + + if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) { + dev_warn(dev, + "voltage dropped below %u%%, " + "date and time is not reliable.\n", + buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75); + } + + dev_dbg(dev, + "%s: raw data is sec=%02x, min=%02x, hr=%02x, " + "mday=%02x, mon=%02x, year=%02x, wday=%02x, " + "sr=%02x, int=%02x", + __func__, + buf[ISL12022_REG_SC], + buf[ISL12022_REG_MN], + buf[ISL12022_REG_HR], + buf[ISL12022_REG_DT], + buf[ISL12022_REG_MO], + buf[ISL12022_REG_YR], + buf[ISL12022_REG_DW], + buf[ISL12022_REG_SR], + buf[ISL12022_REG_INT]); + + tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F); + tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F); + tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F); + tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F); + tm->tm_wday = buf[ISL12022_REG_DW] & 0x07; + tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1; + tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100; + + dev_dbg(dev, "%s: %ptR\n", __func__, tm); + + return 0; +} + +static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct isl12022 *isl12022 = dev_get_drvdata(dev); + struct regmap *regmap = isl12022->regmap; + int ret; + uint8_t buf[ISL12022_REG_DW + 1]; + + dev_dbg(dev, "%s: %ptR\n", __func__, tm); + + /* Ensure the write enable bit is set. */ + ret = regmap_update_bits(regmap, ISL12022_REG_INT, + ISL12022_INT_WRTC, ISL12022_INT_WRTC); + if (ret) + return ret; + + /* hours, minutes and seconds */ + buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec); + buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min); + buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL; + + buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday); + + /* month, 1 - 12 */ + buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1); + + /* year and century */ + buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100); + + buf[ISL12022_REG_DW] = tm->tm_wday & 0x07; + + return regmap_bulk_write(isl12022->regmap, ISL12022_REG_SC, + buf, sizeof(buf)); +} + +static const struct rtc_class_ops isl12022_rtc_ops = { + .read_time = isl12022_rtc_read_time, + .set_time = isl12022_rtc_set_time, +}; + +static const struct regmap_config regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .use_single_write = true, +}; + +static int isl12022_probe(struct i2c_client *client) +{ + struct isl12022 *isl12022; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -ENODEV; + + isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022), + GFP_KERNEL); + if (!isl12022) + return -ENOMEM; + dev_set_drvdata(&client->dev, isl12022); + + isl12022->regmap = devm_regmap_init_i2c(client, ®map_config); + if (IS_ERR(isl12022->regmap)) { + dev_err(&client->dev, "regmap allocation failed\n"); + return PTR_ERR(isl12022->regmap); + } + + isl12022->rtc = devm_rtc_allocate_device(&client->dev); + if (IS_ERR(isl12022->rtc)) + return PTR_ERR(isl12022->rtc); + + isl12022->rtc->ops = &isl12022_rtc_ops; + isl12022->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; + isl12022->rtc->range_max = RTC_TIMESTAMP_END_2099; + + return devm_rtc_register_device(isl12022->rtc); +} + +#ifdef CONFIG_OF +static const struct of_device_id isl12022_dt_match[] = { + { .compatible = "isl,isl12022" }, /* for backward compat., don't use */ + { .compatible = "isil,isl12022" }, + { }, +}; +MODULE_DEVICE_TABLE(of, isl12022_dt_match); +#endif + +static const struct i2c_device_id isl12022_id[] = { + { "isl12022", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, isl12022_id); + +static struct i2c_driver isl12022_driver = { + .driver = { + .name = "rtc-isl12022", +#ifdef CONFIG_OF + .of_match_table = of_match_ptr(isl12022_dt_match), +#endif + }, + .probe_new = isl12022_probe, + .id_table = isl12022_id, +}; + +module_i2c_driver(isl12022_driver); + +MODULE_AUTHOR("roman.fietze@telemotive.de"); +MODULE_DESCRIPTION("ISL 12022 RTC driver"); +MODULE_LICENSE("GPL"); |