diff options
Diffstat (limited to 'drivers/rtc/rtc-isl12057.c')
| -rw-r--r-- | drivers/rtc/rtc-isl12057.c | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-isl12057.c b/drivers/rtc/rtc-isl12057.c new file mode 100644 index 00000000000..7854a656628 --- /dev/null +++ b/drivers/rtc/rtc-isl12057.c @@ -0,0 +1,310 @@ +/* + * rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock + * + * Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org> + * + * This work is largely based on Intersil ISL1208 driver developed by + * Hebert Valerio Riedel <hvr@gnu.org>. + * + * Detailed datasheet on which this development is based is available here: + * + * http://natisbad.org/NAS2/refs/ISL12057.pdf + * + * 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. + */ + +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/rtc.h> +#include <linux/i2c.h> +#include <linux/bcd.h> +#include <linux/rtc.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/regmap.h> + +#define DRV_NAME "rtc-isl12057" + +/* RTC section */ +#define ISL12057_REG_RTC_SC 0x00 /* Seconds */ +#define ISL12057_REG_RTC_MN 0x01 /* Minutes */ +#define ISL12057_REG_RTC_HR 0x02 /* Hours */ +#define ISL12057_REG_RTC_HR_PM BIT(5) /* AM/PM bit in 12h format */ +#define ISL12057_REG_RTC_HR_MIL BIT(6) /* 24h/12h format */ +#define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */ +#define ISL12057_REG_RTC_DT 0x04 /* Date */ +#define ISL12057_REG_RTC_MO 0x05 /* Month */ +#define ISL12057_REG_RTC_YR 0x06 /* Year */ +#define ISL12057_RTC_SEC_LEN 7 + +/* Alarm 1 section */ +#define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */ +#define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */ +#define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */ +#define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */ +#define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */ +#define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */ +#define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */ +#define ISL12057_A1_SEC_LEN 4 + +/* Alarm 2 section */ +#define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */ +#define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */ +#define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */ +#define ISL12057_A2_SEC_LEN 3 + +/* Control/Status registers */ +#define ISL12057_REG_INT 0x0E +#define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */ +#define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */ +#define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */ +#define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */ +#define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */ +#define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */ + +#define ISL12057_REG_SR 0x0F +#define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */ +#define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */ +#define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */ + +/* Register memory map length */ +#define ISL12057_MEM_MAP_LEN 0x10 + +struct isl12057_rtc_data { + struct regmap *regmap; + struct mutex lock; +}; + +static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs) +{ + tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]); + tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]); + + if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */ + tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x0f); + if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM) + tm->tm_hour += 12; + } else { /* 24 hour mode */ + tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f); + } + + tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]); + tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */ + tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO]) - 1; /* starts at 1 */ + tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100; +} + +static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm) +{ + /* + * The clock has an 8 bit wide bcd-coded register for the year. + * tm_year is an offset from 1900 and we are interested in the + * 2000-2099 range, so any value less than 100 is invalid. + */ + if (tm->tm_year < 100) + return -EINVAL; + + regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec); + regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min); + regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */ + regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday); + regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1); + regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year - 100); + regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1); + + return 0; +} + +/* + * Try and match register bits w/ fixed null values to see whether we + * are dealing with an ISL12057. Note: this function is called early + * during init and hence does need mutex protection. + */ +static int isl12057_i2c_validate_chip(struct regmap *regmap) +{ + u8 regs[ISL12057_MEM_MAP_LEN]; + static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8, + 0xc0, 0x60, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x60, 0x7c }; + int ret, i; + + ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN); + if (ret) + return ret; + + for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) { + if (regs[i] & mask[i]) /* check if bits are cleared */ + return -ENODEV; + } + + return 0; +} + +static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + u8 regs[ISL12057_RTC_SEC_LEN]; + int ret; + + mutex_lock(&data->lock); + ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs, + ISL12057_RTC_SEC_LEN); + mutex_unlock(&data->lock); + + if (ret) { + dev_err(dev, "%s: RTC read failed\n", __func__); + return ret; + } + + isl12057_rtc_regs_to_tm(tm, regs); + + return rtc_valid_tm(tm); +} + +static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + u8 regs[ISL12057_RTC_SEC_LEN]; + int ret; + + ret = isl12057_rtc_tm_to_regs(regs, tm); + if (ret) + return ret; + + mutex_lock(&data->lock); + ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs, + ISL12057_RTC_SEC_LEN); + mutex_unlock(&data->lock); + + if (ret) + dev_err(dev, "%s: RTC write failed\n", __func__); + + return ret; +} + +/* + * Check current RTC status and enable/disable what needs to be. Return 0 if + * everything went ok and a negative value upon error. Note: this function + * is called early during init and hence does need mutex protection. + */ +static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap) +{ + int ret; + + /* Enable oscillator if not already running */ + ret = regmap_update_bits(regmap, ISL12057_REG_INT, + ISL12057_REG_INT_EOSC, 0); + if (ret < 0) { + dev_err(dev, "Unable to enable oscillator\n"); + return ret; + } + + /* Clear oscillator failure bit if needed */ + ret = regmap_update_bits(regmap, ISL12057_REG_SR, + ISL12057_REG_SR_OSF, 0); + if (ret < 0) { + dev_err(dev, "Unable to clear oscillator failure bit\n"); + return ret; + } + + /* Clear alarm bit if needed */ + ret = regmap_update_bits(regmap, ISL12057_REG_SR, + ISL12057_REG_SR_A1F, 0); + if (ret < 0) { + dev_err(dev, "Unable to clear alarm bit\n"); + return ret; + } + + return 0; +} + +static const struct rtc_class_ops rtc_ops = { + .read_time = isl12057_rtc_read_time, + .set_time = isl12057_rtc_set_time, +}; + +static struct regmap_config isl12057_rtc_regmap_config = { + .reg_bits = 8, + .val_bits = 8, +}; + +static int isl12057_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct device *dev = &client->dev; + struct isl12057_rtc_data *data; + struct rtc_device *rtc; + struct regmap *regmap; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | + I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_I2C_BLOCK)) + return -ENODEV; + + regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config); + if (IS_ERR(regmap)) { + ret = PTR_ERR(regmap); + dev_err(dev, "regmap allocation failed: %d\n", ret); + return ret; + } + + ret = isl12057_i2c_validate_chip(regmap); + if (ret) + return ret; + + ret = isl12057_check_rtc_status(dev, regmap); + if (ret) + return ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + mutex_init(&data->lock); + data->regmap = regmap; + dev_set_drvdata(dev, data); + + rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + return 0; +} + +#ifdef CONFIG_OF +static struct of_device_id isl12057_dt_match[] = { + { .compatible = "isl,isl12057" }, + { }, +}; +#endif + +static const struct i2c_device_id isl12057_id[] = { + { "isl12057", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, isl12057_id); + +static struct i2c_driver isl12057_driver = { + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(isl12057_dt_match), + }, + .probe = isl12057_probe, + .id_table = isl12057_id, +}; +module_i2c_driver(isl12057_driver); + +MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>"); +MODULE_DESCRIPTION("Intersil ISL12057 RTC driver"); +MODULE_LICENSE("GPL"); |