config RTC_DRV_ABX80X

tristate "Abracon ABx80x"

help

If you say yes here you get support for Abracon AB080X and AB180X

families of ultra-low-power battery- and capacitor-backed real-time

clock chips.

This driver can also be built as a module. If so, the module

will be called rtc-abx80x.

obj-$(CONFIG_RTC_DRV_ABX80X) += rtc-abx80x.o

#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;

/*

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");