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334 lines
7.7 KiB
334 lines
7.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Driver for TI BQ32000 RTC. |
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* |
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* Copyright (C) 2009 Semihalf. |
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* Copyright (C) 2014 Pavel Machek <[email protected]> |
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* |
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* You can get hardware description at |
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* https://www.ti.com/lit/ds/symlink/bq32000.pdf |
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*/ |
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#include <linux/module.h> |
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#include <linux/i2c.h> |
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#include <linux/rtc.h> |
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#include <linux/init.h> |
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#include <linux/errno.h> |
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#include <linux/bcd.h> |
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#define BQ32K_SECONDS 0x00 /* Seconds register address */ |
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#define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */ |
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#define BQ32K_STOP 0x80 /* Oscillator Stop flat */ |
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#define BQ32K_MINUTES 0x01 /* Minutes register address */ |
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#define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */ |
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#define BQ32K_OF 0x80 /* Oscillator Failure flag */ |
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#define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */ |
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#define BQ32K_CENT 0x40 /* Century flag */ |
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#define BQ32K_CENT_EN 0x80 /* Century flag enable bit */ |
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#define BQ32K_CALIBRATION 0x07 /* CAL_CFG1, calibration and control */ |
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#define BQ32K_TCH2 0x08 /* Trickle charge enable */ |
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#define BQ32K_CFG2 0x09 /* Trickle charger control */ |
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#define BQ32K_TCFE BIT(6) /* Trickle charge FET bypass */ |
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#define MAX_LEN 10 /* Maximum number of consecutive |
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* register for this particular RTC. |
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*/ |
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struct bq32k_regs { |
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uint8_t seconds; |
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uint8_t minutes; |
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uint8_t cent_hours; |
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uint8_t day; |
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uint8_t date; |
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uint8_t month; |
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uint8_t years; |
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}; |
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static struct i2c_driver bq32k_driver; |
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static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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struct i2c_msg msgs[] = { |
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{ |
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.addr = client->addr, |
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.flags = 0, |
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.len = 1, |
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.buf = &off, |
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}, { |
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.addr = client->addr, |
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.flags = I2C_M_RD, |
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.len = len, |
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.buf = data, |
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} |
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}; |
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if (i2c_transfer(client->adapter, msgs, 2) == 2) |
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return 0; |
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return -EIO; |
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} |
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static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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uint8_t buffer[MAX_LEN + 1]; |
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buffer[0] = off; |
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memcpy(&buffer[1], data, len); |
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if (i2c_master_send(client, buffer, len + 1) == len + 1) |
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return 0; |
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return -EIO; |
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} |
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static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct bq32k_regs regs; |
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int error; |
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error = bq32k_read(dev, ®s, 0, sizeof(regs)); |
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if (error) |
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return error; |
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/* |
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* In case of oscillator failure, the register contents should be |
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* considered invalid. The flag is cleared the next time the RTC is set. |
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*/ |
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if (regs.minutes & BQ32K_OF) |
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return -EINVAL; |
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tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK); |
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tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK); |
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tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK); |
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tm->tm_mday = bcd2bin(regs.date); |
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tm->tm_wday = bcd2bin(regs.day) - 1; |
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tm->tm_mon = bcd2bin(regs.month) - 1; |
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tm->tm_year = bcd2bin(regs.years) + |
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((regs.cent_hours & BQ32K_CENT) ? 100 : 0); |
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return 0; |
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} |
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static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct bq32k_regs regs; |
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regs.seconds = bin2bcd(tm->tm_sec); |
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regs.minutes = bin2bcd(tm->tm_min); |
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regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN; |
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regs.day = bin2bcd(tm->tm_wday + 1); |
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regs.date = bin2bcd(tm->tm_mday); |
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regs.month = bin2bcd(tm->tm_mon + 1); |
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if (tm->tm_year >= 100) { |
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regs.cent_hours |= BQ32K_CENT; |
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regs.years = bin2bcd(tm->tm_year - 100); |
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} else |
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regs.years = bin2bcd(tm->tm_year); |
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return bq32k_write(dev, ®s, 0, sizeof(regs)); |
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} |
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static const struct rtc_class_ops bq32k_rtc_ops = { |
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.read_time = bq32k_rtc_read_time, |
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.set_time = bq32k_rtc_set_time, |
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}; |
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static int trickle_charger_of_init(struct device *dev, struct device_node *node) |
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{ |
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unsigned char reg; |
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int error; |
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u32 ohms = 0; |
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if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms)) |
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return 0; |
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switch (ohms) { |
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case 180+940: |
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/* |
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* TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging |
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* over diode and 940ohm resistor) |
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*/ |
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if (of_property_read_bool(node, "trickle-diode-disable")) { |
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dev_err(dev, "diode and resistor mismatch\n"); |
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return -EINVAL; |
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} |
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reg = 0x05; |
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break; |
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case 180+20000: |
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/* diode disabled */ |
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if (!of_property_read_bool(node, "trickle-diode-disable")) { |
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dev_err(dev, "bq32k: diode and resistor mismatch\n"); |
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return -EINVAL; |
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} |
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reg = 0x45; |
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break; |
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default: |
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dev_err(dev, "invalid resistor value (%d)\n", ohms); |
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return -EINVAL; |
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} |
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error = bq32k_write(dev, ®, BQ32K_CFG2, 1); |
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if (error) |
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return error; |
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reg = 0x20; |
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error = bq32k_write(dev, ®, BQ32K_TCH2, 1); |
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if (error) |
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return error; |
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dev_info(dev, "Enabled trickle RTC battery charge.\n"); |
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return 0; |
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} |
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static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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int reg, error; |
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error = bq32k_read(dev, ®, BQ32K_CFG2, 1); |
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if (error) |
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return error; |
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return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0); |
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} |
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static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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int reg, enable, error; |
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if (kstrtoint(buf, 0, &enable)) |
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return -EINVAL; |
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error = bq32k_read(dev, ®, BQ32K_CFG2, 1); |
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if (error) |
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return error; |
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if (enable) { |
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reg |= BQ32K_TCFE; |
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error = bq32k_write(dev, ®, BQ32K_CFG2, 1); |
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if (error) |
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return error; |
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dev_info(dev, "Enabled trickle charge FET bypass.\n"); |
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} else { |
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reg &= ~BQ32K_TCFE; |
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error = bq32k_write(dev, ®, BQ32K_CFG2, 1); |
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if (error) |
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return error; |
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dev_info(dev, "Disabled trickle charge FET bypass.\n"); |
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} |
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return count; |
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} |
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static DEVICE_ATTR(trickle_charge_bypass, 0644, |
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bq32k_sysfs_show_tricklecharge_bypass, |
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bq32k_sysfs_store_tricklecharge_bypass); |
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static int bq32k_sysfs_register(struct device *dev) |
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{ |
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return device_create_file(dev, &dev_attr_trickle_charge_bypass); |
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} |
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static void bq32k_sysfs_unregister(struct device *dev) |
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{ |
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device_remove_file(dev, &dev_attr_trickle_charge_bypass); |
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} |
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static int bq32k_probe(struct i2c_client *client, |
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const struct i2c_device_id *id) |
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{ |
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struct device *dev = &client->dev; |
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struct rtc_device *rtc; |
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uint8_t reg; |
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int error; |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
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return -ENODEV; |
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/* Check Oscillator Stop flag */ |
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error = bq32k_read(dev, ®, BQ32K_SECONDS, 1); |
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if (!error && (reg & BQ32K_STOP)) { |
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dev_warn(dev, "Oscillator was halted. Restarting...\n"); |
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reg &= ~BQ32K_STOP; |
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error = bq32k_write(dev, ®, BQ32K_SECONDS, 1); |
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} |
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if (error) |
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return error; |
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/* Check Oscillator Failure flag */ |
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error = bq32k_read(dev, ®, BQ32K_MINUTES, 1); |
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if (error) |
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return error; |
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if (reg & BQ32K_OF) |
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dev_warn(dev, "Oscillator Failure. Check RTC battery.\n"); |
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if (client->dev.of_node) |
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trickle_charger_of_init(dev, client->dev.of_node); |
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rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name, |
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&bq32k_rtc_ops, THIS_MODULE); |
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if (IS_ERR(rtc)) |
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return PTR_ERR(rtc); |
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error = bq32k_sysfs_register(&client->dev); |
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if (error) { |
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dev_err(&client->dev, |
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"Unable to create sysfs entries for rtc bq32000\n"); |
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return error; |
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} |
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i2c_set_clientdata(client, rtc); |
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return 0; |
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} |
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static int bq32k_remove(struct i2c_client *client) |
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{ |
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bq32k_sysfs_unregister(&client->dev); |
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return 0; |
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} |
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static const struct i2c_device_id bq32k_id[] = { |
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{ "bq32000", 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, bq32k_id); |
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static const __maybe_unused struct of_device_id bq32k_of_match[] = { |
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{ .compatible = "ti,bq32000" }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, bq32k_of_match); |
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static struct i2c_driver bq32k_driver = { |
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.driver = { |
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.name = "bq32k", |
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.of_match_table = of_match_ptr(bq32k_of_match), |
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}, |
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.probe = bq32k_probe, |
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.remove = bq32k_remove, |
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.id_table = bq32k_id, |
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}; |
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module_i2c_driver(bq32k_driver); |
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MODULE_AUTHOR("Semihalf, Piotr Ziecik <[email protected]>"); |
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MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver"); |
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MODULE_LICENSE("GPL");
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