diff options
Diffstat (limited to 'drivers/rtc/rtc-abx80x.c')
| -rw-r--r-- | drivers/rtc/rtc-abx80x.c | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c new file mode 100644 index 000000000000..4337c3bc6ace --- /dev/null +++ b/drivers/rtc/rtc-abx80x.c @@ -0,0 +1,307 @@ +/* + * 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(1) +#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"); |