// SPDX-License-Identifier: GPL-2.0-only /* * Driver for TI BQ32000 RTC. * * Copyright (C) 2009 Semihalf. * Copyright (C) 2014 Pavel Machek <pavel@denx.de> * * 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 */ #define BQ32K_TCFE BIT(6) /* Trickle charge FET bypass */ #define MAX_LEN 10 /* Maximum number of consecutive * register for this particular RTC. */ 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[MAX_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; /* * In case of oscillator failure, the register contents should be * considered invalid. The flag is cleared the next time the RTC is set. */ if (regs.minutes & BQ32K_OF) return -EINVAL; tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK); tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_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 0; } 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 ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev, struct device_attribute *attr, char *buf) { int reg, error; error = bq32k_read(dev, ®, BQ32K_CFG2, 1); if (error) return error; return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0); } static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int reg, enable, error; if (kstrtoint(buf, 0, &enable)) return -EINVAL; error = bq32k_read(dev, ®, BQ32K_CFG2, 1); if (error) return error; if (enable) { reg |= BQ32K_TCFE; error = bq32k_write(dev, ®, BQ32K_CFG2, 1); if (error) return error; dev_info(dev, "Enabled trickle charge FET bypass.\n"); } else { reg &= ~BQ32K_TCFE; error = bq32k_write(dev, ®, BQ32K_CFG2, 1); if (error) return error; dev_info(dev, "Disabled trickle charge FET bypass.\n"); } return count; } static DEVICE_ATTR(trickle_charge_bypass, 0644, bq32k_sysfs_show_tricklecharge_bypass, bq32k_sysfs_store_tricklecharge_bypass); static int bq32k_sysfs_register(struct device *dev) { return device_create_file(dev, &dev_attr_trickle_charge_bypass); } static void bq32k_sysfs_unregister(struct device *dev) { device_remove_file(dev, &dev_attr_trickle_charge_bypass); } 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) return error; if (reg & BQ32K_OF) dev_warn(dev, "Oscillator Failure. Check RTC battery.\n"); 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); error = bq32k_sysfs_register(&client->dev); if (error) { dev_err(&client->dev, "Unable to create sysfs entries for rtc bq32000\n"); return error; } i2c_set_clientdata(client, rtc); return 0; } static int bq32k_remove(struct i2c_client *client) { bq32k_sysfs_unregister(&client->dev); return 0; } static const struct i2c_device_id bq32k_id[] = { { "bq32000", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, bq32k_id); static const struct of_device_id bq32k_of_match[] = { { .compatible = "ti,bq32000" }, { } }; MODULE_DEVICE_TABLE(of, bq32k_of_match); static struct i2c_driver bq32k_driver = { .driver = { .name = "bq32k", .of_match_table = of_match_ptr(bq32k_of_match), }, .probe = bq32k_probe, .remove = 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");