| /* |
| * Driver for TI BQ32000 RTC. |
| * |
| * Copyright (C) 2009 Semihalf. |
| * Copyright (C) 2014 Pavel Machek <pavel@denx.de> |
| * |
| * 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. |
| * |
| * You can get hardware description at |
| * http://www.ti.com/lit/ds/symlink/bq32000.pdf |
| */ |
| |
| #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 */ |
| |
| #define BQ32K_CALIBRATION 0x07 /* CAL_CFG1, calibration and control */ |
| #define BQ32K_TCH2 0x08 /* Trickle charge enable */ |
| #define BQ32K_CFG2 0x09 /* Trickle charger control */ |
| |
| 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 trickle_charger_of_init(struct device *dev, struct device_node *node) |
| { |
| unsigned char reg; |
| int error; |
| u32 ohms = 0; |
| |
| if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms)) |
| return 0; |
| |
| switch (ohms) { |
| case 180+940: |
| /* |
| * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging |
| * over diode and 940ohm resistor) |
| */ |
| |
| if (of_property_read_bool(node, "trickle-diode-disable")) { |
| dev_err(dev, "diode and resistor mismatch\n"); |
| return -EINVAL; |
| } |
| reg = 0x05; |
| break; |
| |
| case 180+20000: |
| /* diode disabled */ |
| |
| if (!of_property_read_bool(node, "trickle-diode-disable")) { |
| dev_err(dev, "bq32k: diode and resistor mismatch\n"); |
| return -EINVAL; |
| } |
| reg = 0x45; |
| break; |
| |
| default: |
| dev_err(dev, "invalid resistor value (%d)\n", ohms); |
| return -EINVAL; |
| } |
| |
| error = bq32k_write(dev, ®, BQ32K_CFG2, 1); |
| if (error) |
| return error; |
| |
| reg = 0x20; |
| error = bq32k_write(dev, ®, BQ32K_TCH2, 1); |
| if (error) |
| return error; |
| |
| dev_info(dev, "Enabled trickle RTC battery charge.\n"); |
| return 0; |
| } |
| |
| 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; |
| |
| if (client->dev.of_node) |
| trickle_charger_of_init(dev, client->dev.of_node); |
| |
| rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name, |
| &bq32k_rtc_ops, THIS_MODULE); |
| if (IS_ERR(rtc)) |
| return PTR_ERR(rtc); |
| |
| i2c_set_clientdata(client, 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", |
| }, |
| .probe = bq32k_probe, |
| .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"); |