/* * Driver for TI BQ32000 RTC. * * Copyright (C) 2009 Semihalf. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/module.h> #include <linux/i2c.h> #include <linux/rtc.h> #include <linux/init.h> #include <linux/errno.h> #include <linux/bcd.h> #define BQ32K_SECONDS 0x00 /* Seconds register address */ #define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */ #define BQ32K_STOP 0x80 /* Oscillator Stop flat */ #define BQ32K_MINUTES 0x01 /* Minutes register address */ #define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */ #define BQ32K_OF 0x80 /* Oscillator Failure flag */ #define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */ #define BQ32K_CENT 0x40 /* Century flag */ #define BQ32K_CENT_EN 0x80 /* Century flag enable bit */ struct bq32k_regs { uint8_t seconds; uint8_t minutes; uint8_t cent_hours; uint8_t day; uint8_t date; uint8_t month; uint8_t years; }; static struct i2c_driver bq32k_driver; static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len) { struct i2c_client *client = to_i2c_client(dev); struct i2c_msg msgs[] = { { .addr = client->addr, .flags = 0, .len = 1, .buf = &off, }, { .addr = client->addr, .flags = I2C_M_RD, .len = len, .buf = data, } }; if (i2c_transfer(client->adapter, msgs, 2) == 2) return 0; return -EIO; } static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len) { struct i2c_client *client = to_i2c_client(dev); uint8_t buffer[len + 1]; buffer[0] = off; memcpy(&buffer[1], data, len); if (i2c_master_send(client, buffer, len + 1) == len + 1) return 0; return -EIO; } static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct bq32k_regs regs; int error; error = bq32k_read(dev, ®s, 0, sizeof(regs)); if (error) return error; tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK); tm->tm_min = bcd2bin(regs.minutes & BQ32K_SECONDS_MASK); tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK); tm->tm_mday = bcd2bin(regs.date); tm->tm_wday = bcd2bin(regs.day) - 1; tm->tm_mon = bcd2bin(regs.month) - 1; tm->tm_year = bcd2bin(regs.years) + ((regs.cent_hours & BQ32K_CENT) ? 100 : 0); return rtc_valid_tm(tm); } static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct bq32k_regs regs; regs.seconds = bin2bcd(tm->tm_sec); regs.minutes = bin2bcd(tm->tm_min); regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN; regs.day = bin2bcd(tm->tm_wday + 1); regs.date = bin2bcd(tm->tm_mday); regs.month = bin2bcd(tm->tm_mon + 1); if (tm->tm_year >= 100) { regs.cent_hours |= BQ32K_CENT; regs.years = bin2bcd(tm->tm_year - 100); } else regs.years = bin2bcd(tm->tm_year); return bq32k_write(dev, ®s, 0, sizeof(regs)); } static const struct rtc_class_ops bq32k_rtc_ops = { .read_time = bq32k_rtc_read_time, .set_time = bq32k_rtc_set_time, }; static int bq32k_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device *dev = &client->dev; struct rtc_device *rtc; uint8_t reg; int error; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) return -ENODEV; /* Check Oscillator Stop flag */ error = bq32k_read(dev, ®, BQ32K_SECONDS, 1); if (!error && (reg & BQ32K_STOP)) { dev_warn(dev, "Oscillator was halted. Restarting...\n"); reg &= ~BQ32K_STOP; error = bq32k_write(dev, ®, BQ32K_SECONDS, 1); } if (error) return error; /* Check Oscillator Failure flag */ error = bq32k_read(dev, ®, BQ32K_MINUTES, 1); if (!error && (reg & BQ32K_OF)) { dev_warn(dev, "Oscillator Failure. Check RTC battery.\n"); reg &= ~BQ32K_OF; error = bq32k_write(dev, ®, BQ32K_MINUTES, 1); } if (error) return error; rtc = rtc_device_register(bq32k_driver.driver.name, &client->dev, &bq32k_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); i2c_set_clientdata(client, rtc); return 0; } static int __devexit bq32k_remove(struct i2c_client *client) { struct rtc_device *rtc = i2c_get_clientdata(client); rtc_device_unregister(rtc); return 0; } static const struct i2c_device_id bq32k_id[] = { { "bq32000", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, bq32k_id); static struct i2c_driver bq32k_driver = { .driver = { .name = "bq32k", .owner = THIS_MODULE, }, .probe = bq32k_probe, .remove = __devexit_p(bq32k_remove), .id_table = bq32k_id, }; module_i2c_driver(bq32k_driver); MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>"); MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver"); MODULE_LICENSE("GPL");