/* * A driver for the I2C members of the Abracon AB x8xx RTC family, * and compatible: AB 1805 and AB 0805 * * Copyright 2014-2015 Macq S.A. * * Author: Philippe De Muyter <phdm@macqel.be> * Author: Alexandre Belloni <alexandre.belloni@free-electrons.com> * * 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/bcd.h> #include <linux/i2c.h> #include <linux/module.h> #include <linux/rtc.h> #define ABX8XX_REG_HTH 0x00 #define ABX8XX_REG_SC 0x01 #define ABX8XX_REG_MN 0x02 #define ABX8XX_REG_HR 0x03 #define ABX8XX_REG_DA 0x04 #define ABX8XX_REG_MO 0x05 #define ABX8XX_REG_YR 0x06 #define ABX8XX_REG_WD 0x07 #define ABX8XX_REG_CTRL1 0x10 #define ABX8XX_CTRL_WRITE BIT(0) #define ABX8XX_CTRL_12_24 BIT(6) #define ABX8XX_REG_CFG_KEY 0x1f #define ABX8XX_CFG_KEY_MISC 0x9d #define ABX8XX_REG_ID0 0x28 #define ABX8XX_REG_TRICKLE 0x20 #define ABX8XX_TRICKLE_CHARGE_ENABLE 0xa0 #define ABX8XX_TRICKLE_STANDARD_DIODE 0x8 #define ABX8XX_TRICKLE_SCHOTTKY_DIODE 0x4 static u8 trickle_resistors[] = {0, 3, 6, 11}; enum abx80x_chip {AB0801, AB0803, AB0804, AB0805, AB1801, AB1803, AB1804, AB1805, ABX80X}; struct abx80x_cap { u16 pn; bool has_tc; }; static struct abx80x_cap abx80x_caps[] = { [AB0801] = {.pn = 0x0801}, [AB0803] = {.pn = 0x0803}, [AB0804] = {.pn = 0x0804, .has_tc = true}, [AB0805] = {.pn = 0x0805, .has_tc = true}, [AB1801] = {.pn = 0x1801}, [AB1803] = {.pn = 0x1803}, [AB1804] = {.pn = 0x1804, .has_tc = true}, [AB1805] = {.pn = 0x1805, .has_tc = true}, [ABX80X] = {.pn = 0} }; static struct i2c_driver abx80x_driver; static int abx80x_enable_trickle_charger(struct i2c_client *client, u8 trickle_cfg) { int err; /* * Write the configuration key register to enable access to the Trickle * register */ err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY, ABX8XX_CFG_KEY_MISC); if (err < 0) { dev_err(&client->dev, "Unable to write configuration key\n"); return -EIO; } err = i2c_smbus_write_byte_data(client, ABX8XX_REG_TRICKLE, ABX8XX_TRICKLE_CHARGE_ENABLE | trickle_cfg); if (err < 0) { dev_err(&client->dev, "Unable to write trickle register\n"); return -EIO; } return 0; } static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); unsigned char buf[8]; int err; err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH, sizeof(buf), buf); if (err < 0) { dev_err(&client->dev, "Unable to read date\n"); return -EIO; } tm->tm_sec = bcd2bin(buf[ABX8XX_REG_SC] & 0x7F); tm->tm_min = bcd2bin(buf[ABX8XX_REG_MN] & 0x7F); tm->tm_hour = bcd2bin(buf[ABX8XX_REG_HR] & 0x3F); tm->tm_wday = buf[ABX8XX_REG_WD] & 0x7; tm->tm_mday = bcd2bin(buf[ABX8XX_REG_DA] & 0x3F); tm->tm_mon = bcd2bin(buf[ABX8XX_REG_MO] & 0x1F) - 1; tm->tm_year = bcd2bin(buf[ABX8XX_REG_YR]) + 100; err = rtc_valid_tm(tm); if (err < 0) dev_err(&client->dev, "retrieved date/time is not valid.\n"); return err; } static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); unsigned char buf[8]; int err; if (tm->tm_year < 100) return -EINVAL; buf[ABX8XX_REG_HTH] = 0; buf[ABX8XX_REG_SC] = bin2bcd(tm->tm_sec); buf[ABX8XX_REG_MN] = bin2bcd(tm->tm_min); buf[ABX8XX_REG_HR] = bin2bcd(tm->tm_hour); buf[ABX8XX_REG_DA] = bin2bcd(tm->tm_mday); buf[ABX8XX_REG_MO] = bin2bcd(tm->tm_mon + 1); buf[ABX8XX_REG_YR] = bin2bcd(tm->tm_year - 100); buf[ABX8XX_REG_WD] = tm->tm_wday; err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_HTH, sizeof(buf), buf); if (err < 0) { dev_err(&client->dev, "Unable to write to date registers\n"); return -EIO; } return 0; } static const struct rtc_class_ops abx80x_rtc_ops = { .read_time = abx80x_rtc_read_time, .set_time = abx80x_rtc_set_time, }; static int abx80x_dt_trickle_cfg(struct device_node *np) { const char *diode; int trickle_cfg = 0; int i, ret; u32 tmp; ret = of_property_read_string(np, "abracon,tc-diode", &diode); if (ret) return ret; if (!strcmp(diode, "standard")) trickle_cfg |= ABX8XX_TRICKLE_STANDARD_DIODE; else if (!strcmp(diode, "schottky")) trickle_cfg |= ABX8XX_TRICKLE_SCHOTTKY_DIODE; else return -EINVAL; ret = of_property_read_u32(np, "abracon,tc-resistor", &tmp); if (ret) return ret; for (i = 0; i < sizeof(trickle_resistors); i++) if (trickle_resistors[i] == tmp) break; if (i == sizeof(trickle_resistors)) return -EINVAL; return (trickle_cfg | i); } static int abx80x_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device_node *np = client->dev.of_node; struct rtc_device *rtc; int i, data, err, trickle_cfg = -EINVAL; char buf[7]; unsigned int part = id->driver_data; unsigned int partnumber; unsigned int majrev, minrev; unsigned int lot; unsigned int wafer; unsigned int uid; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) return -ENODEV; err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ID0, sizeof(buf), buf); if (err < 0) { dev_err(&client->dev, "Unable to read partnumber\n"); return -EIO; } partnumber = (buf[0] << 8) | buf[1]; majrev = buf[2] >> 3; minrev = buf[2] & 0x7; lot = ((buf[4] & 0x80) << 2) | ((buf[6] & 0x80) << 1) | buf[3]; uid = ((buf[4] & 0x7f) << 8) | buf[5]; wafer = (buf[6] & 0x7c) >> 2; dev_info(&client->dev, "model %04x, revision %u.%u, lot %x, wafer %x, uid %x\n", partnumber, majrev, minrev, lot, wafer, uid); data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL1); if (data < 0) { dev_err(&client->dev, "Unable to read control register\n"); return -EIO; } err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL1, ((data & ~ABX8XX_CTRL_12_24) | ABX8XX_CTRL_WRITE)); if (err < 0) { dev_err(&client->dev, "Unable to write control register\n"); return -EIO; } /* part autodetection */ if (part == ABX80X) { for (i = 0; abx80x_caps[i].pn; i++) if (partnumber == abx80x_caps[i].pn) break; if (abx80x_caps[i].pn == 0) { dev_err(&client->dev, "Unknown part: %04x\n", partnumber); return -EINVAL; } part = i; } if (partnumber != abx80x_caps[part].pn) { dev_err(&client->dev, "partnumber mismatch %04x != %04x\n", partnumber, abx80x_caps[part].pn); return -EINVAL; } if (np && abx80x_caps[part].has_tc) trickle_cfg = abx80x_dt_trickle_cfg(np); if (trickle_cfg > 0) { dev_info(&client->dev, "Enabling trickle charger: %02x\n", trickle_cfg); abx80x_enable_trickle_charger(client, trickle_cfg); } rtc = devm_rtc_device_register(&client->dev, abx80x_driver.driver.name, &abx80x_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); i2c_set_clientdata(client, rtc); return 0; } static int abx80x_remove(struct i2c_client *client) { return 0; } static const struct i2c_device_id abx80x_id[] = { { "abx80x", ABX80X }, { "ab0801", AB0801 }, { "ab0803", AB0803 }, { "ab0804", AB0804 }, { "ab0805", AB0805 }, { "ab1801", AB1801 }, { "ab1803", AB1803 }, { "ab1804", AB1804 }, { "ab1805", AB1805 }, { } }; MODULE_DEVICE_TABLE(i2c, abx80x_id); static struct i2c_driver abx80x_driver = { .driver = { .name = "rtc-abx80x", }, .probe = abx80x_probe, .remove = abx80x_remove, .id_table = abx80x_id, }; module_i2c_driver(abx80x_driver); MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>"); MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>"); MODULE_DESCRIPTION("Abracon ABX80X RTC driver"); MODULE_LICENSE("GPL v2");