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592 lines
13 KiB
592 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2012 Avionic Design GmbH |
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*/ |
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#include <linux/bcd.h> |
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#include <linux/i2c.h> |
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#include <linux/module.h> |
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#include <linux/rtc.h> |
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#include <linux/of.h> |
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#include <linux/pm_wakeirq.h> |
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#define PCF8523_REG_CONTROL1 0x00 |
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#define PCF8523_CONTROL1_CAP_SEL BIT(7) |
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#define PCF8523_CONTROL1_STOP BIT(5) |
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#define PCF8523_CONTROL1_AIE BIT(1) |
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#define PCF8523_REG_CONTROL2 0x01 |
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#define PCF8523_CONTROL2_AF BIT(3) |
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#define PCF8523_REG_CONTROL3 0x02 |
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#define PCF8523_CONTROL3_PM_BLD BIT(7) /* battery low detection disabled */ |
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#define PCF8523_CONTROL3_PM_VDD BIT(6) /* switch-over disabled */ |
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#define PCF8523_CONTROL3_PM_DSM BIT(5) /* direct switching mode */ |
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#define PCF8523_CONTROL3_PM_MASK 0xe0 |
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#define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */ |
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#define PCF8523_REG_SECONDS 0x03 |
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#define PCF8523_SECONDS_OS BIT(7) |
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#define PCF8523_REG_MINUTES 0x04 |
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#define PCF8523_REG_HOURS 0x05 |
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#define PCF8523_REG_DAYS 0x06 |
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#define PCF8523_REG_WEEKDAYS 0x07 |
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#define PCF8523_REG_MONTHS 0x08 |
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#define PCF8523_REG_YEARS 0x09 |
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#define PCF8523_REG_MINUTE_ALARM 0x0a |
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#define PCF8523_REG_HOUR_ALARM 0x0b |
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#define PCF8523_REG_DAY_ALARM 0x0c |
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#define PCF8523_REG_WEEKDAY_ALARM 0x0d |
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#define ALARM_DIS BIT(7) |
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#define PCF8523_REG_OFFSET 0x0e |
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#define PCF8523_OFFSET_MODE BIT(7) |
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#define PCF8523_TMR_CLKOUT_CTRL 0x0f |
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struct pcf8523 { |
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struct rtc_device *rtc; |
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struct i2c_client *client; |
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}; |
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static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep) |
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{ |
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struct i2c_msg msgs[2]; |
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u8 value = 0; |
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int err; |
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msgs[0].addr = client->addr; |
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msgs[0].flags = 0; |
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msgs[0].len = sizeof(reg); |
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msgs[0].buf = ® |
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msgs[1].addr = client->addr; |
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msgs[1].flags = I2C_M_RD; |
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msgs[1].len = sizeof(value); |
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msgs[1].buf = &value; |
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err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); |
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if (err < 0) |
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return err; |
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*valuep = value; |
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return 0; |
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} |
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static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value) |
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{ |
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u8 buffer[2] = { reg, value }; |
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struct i2c_msg msg; |
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int err; |
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msg.addr = client->addr; |
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msg.flags = 0; |
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msg.len = sizeof(buffer); |
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msg.buf = buffer; |
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err = i2c_transfer(client->adapter, &msg, 1); |
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if (err < 0) |
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return err; |
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return 0; |
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} |
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static int pcf8523_voltage_low(struct i2c_client *client) |
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{ |
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u8 value; |
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int err; |
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err = pcf8523_read(client, PCF8523_REG_CONTROL3, &value); |
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if (err < 0) |
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return err; |
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return !!(value & PCF8523_CONTROL3_BLF); |
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} |
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static int pcf8523_load_capacitance(struct i2c_client *client) |
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{ |
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u32 load; |
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u8 value; |
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int err; |
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err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value); |
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if (err < 0) |
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return err; |
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load = 12500; |
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of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads", |
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&load); |
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switch (load) { |
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default: |
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dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500", |
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load); |
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fallthrough; |
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case 12500: |
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value |= PCF8523_CONTROL1_CAP_SEL; |
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break; |
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case 7000: |
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value &= ~PCF8523_CONTROL1_CAP_SEL; |
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break; |
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} |
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err = pcf8523_write(client, PCF8523_REG_CONTROL1, value); |
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return err; |
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} |
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static int pcf8523_set_pm(struct i2c_client *client, u8 pm) |
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{ |
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u8 value; |
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int err; |
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err = pcf8523_read(client, PCF8523_REG_CONTROL3, &value); |
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if (err < 0) |
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return err; |
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value = (value & ~PCF8523_CONTROL3_PM_MASK) | pm; |
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err = pcf8523_write(client, PCF8523_REG_CONTROL3, value); |
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if (err < 0) |
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return err; |
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return 0; |
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} |
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static irqreturn_t pcf8523_irq(int irq, void *dev_id) |
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{ |
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struct pcf8523 *pcf8523 = i2c_get_clientdata(dev_id); |
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u8 value; |
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int err; |
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err = pcf8523_read(pcf8523->client, PCF8523_REG_CONTROL2, &value); |
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if (err < 0) |
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return IRQ_HANDLED; |
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if (value & PCF8523_CONTROL2_AF) { |
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value &= ~PCF8523_CONTROL2_AF; |
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pcf8523_write(pcf8523->client, PCF8523_REG_CONTROL2, value); |
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rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF); |
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return IRQ_HANDLED; |
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} |
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return IRQ_NONE; |
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} |
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static int pcf8523_stop_rtc(struct i2c_client *client) |
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{ |
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u8 value; |
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int err; |
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err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value); |
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if (err < 0) |
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return err; |
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value |= PCF8523_CONTROL1_STOP; |
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err = pcf8523_write(client, PCF8523_REG_CONTROL1, value); |
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if (err < 0) |
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return err; |
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return 0; |
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} |
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static int pcf8523_start_rtc(struct i2c_client *client) |
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{ |
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u8 value; |
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int err; |
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err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value); |
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if (err < 0) |
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return err; |
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value &= ~PCF8523_CONTROL1_STOP; |
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err = pcf8523_write(client, PCF8523_REG_CONTROL1, value); |
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if (err < 0) |
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return err; |
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return 0; |
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} |
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static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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u8 start = PCF8523_REG_SECONDS, regs[7]; |
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struct i2c_msg msgs[2]; |
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int err; |
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err = pcf8523_voltage_low(client); |
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if (err < 0) { |
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return err; |
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} else if (err > 0) { |
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dev_err(dev, "low voltage detected, time is unreliable\n"); |
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return -EINVAL; |
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} |
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msgs[0].addr = client->addr; |
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msgs[0].flags = 0; |
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msgs[0].len = 1; |
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msgs[0].buf = &start; |
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msgs[1].addr = client->addr; |
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msgs[1].flags = I2C_M_RD; |
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msgs[1].len = sizeof(regs); |
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msgs[1].buf = regs; |
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err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); |
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if (err < 0) |
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return err; |
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if (regs[0] & PCF8523_SECONDS_OS) { |
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/* |
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* If the oscillator was stopped, try to clear the flag. Upon |
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* power-up the flag is always set, but if we cannot clear it |
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* the oscillator isn't running properly for some reason. The |
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* sensible thing therefore is to return an error, signalling |
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* that the clock cannot be assumed to be correct. |
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*/ |
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regs[0] &= ~PCF8523_SECONDS_OS; |
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err = pcf8523_write(client, PCF8523_REG_SECONDS, regs[0]); |
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if (err < 0) |
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return err; |
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err = pcf8523_read(client, PCF8523_REG_SECONDS, ®s[0]); |
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if (err < 0) |
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return err; |
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if (regs[0] & PCF8523_SECONDS_OS) |
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return -EAGAIN; |
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} |
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tm->tm_sec = bcd2bin(regs[0] & 0x7f); |
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tm->tm_min = bcd2bin(regs[1] & 0x7f); |
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tm->tm_hour = bcd2bin(regs[2] & 0x3f); |
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tm->tm_mday = bcd2bin(regs[3] & 0x3f); |
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tm->tm_wday = regs[4] & 0x7; |
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tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1; |
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tm->tm_year = bcd2bin(regs[6]) + 100; |
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return 0; |
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} |
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static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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struct i2c_msg msg; |
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u8 regs[8]; |
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int err; |
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err = pcf8523_stop_rtc(client); |
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if (err < 0) |
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return err; |
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regs[0] = PCF8523_REG_SECONDS; |
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/* This will purposely overwrite PCF8523_SECONDS_OS */ |
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regs[1] = bin2bcd(tm->tm_sec); |
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regs[2] = bin2bcd(tm->tm_min); |
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regs[3] = bin2bcd(tm->tm_hour); |
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regs[4] = bin2bcd(tm->tm_mday); |
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regs[5] = tm->tm_wday; |
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regs[6] = bin2bcd(tm->tm_mon + 1); |
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regs[7] = bin2bcd(tm->tm_year - 100); |
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msg.addr = client->addr; |
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msg.flags = 0; |
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msg.len = sizeof(regs); |
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msg.buf = regs; |
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err = i2c_transfer(client->adapter, &msg, 1); |
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if (err < 0) { |
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/* |
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* If the time cannot be set, restart the RTC anyway. Note |
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* that errors are ignored if the RTC cannot be started so |
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* that we have a chance to propagate the original error. |
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*/ |
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pcf8523_start_rtc(client); |
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return err; |
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} |
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return pcf8523_start_rtc(client); |
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} |
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static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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u8 start = PCF8523_REG_MINUTE_ALARM, regs[4]; |
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struct i2c_msg msgs[2]; |
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u8 value; |
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int err; |
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msgs[0].addr = client->addr; |
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msgs[0].flags = 0; |
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msgs[0].len = 1; |
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msgs[0].buf = &start; |
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msgs[1].addr = client->addr; |
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msgs[1].flags = I2C_M_RD; |
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msgs[1].len = sizeof(regs); |
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msgs[1].buf = regs; |
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err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); |
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if (err < 0) |
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return err; |
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tm->time.tm_sec = 0; |
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tm->time.tm_min = bcd2bin(regs[0] & 0x7F); |
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tm->time.tm_hour = bcd2bin(regs[1] & 0x3F); |
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tm->time.tm_mday = bcd2bin(regs[2] & 0x3F); |
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tm->time.tm_wday = bcd2bin(regs[3] & 0x7); |
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err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value); |
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if (err < 0) |
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return err; |
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tm->enabled = !!(value & PCF8523_CONTROL1_AIE); |
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err = pcf8523_read(client, PCF8523_REG_CONTROL2, &value); |
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if (err < 0) |
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return err; |
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tm->pending = !!(value & PCF8523_CONTROL2_AF); |
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return 0; |
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} |
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static int pcf8523_irq_enable(struct device *dev, unsigned int enabled) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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u8 value; |
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int err; |
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err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value); |
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if (err < 0) |
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return err; |
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value &= PCF8523_CONTROL1_AIE; |
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if (enabled) |
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value |= PCF8523_CONTROL1_AIE; |
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err = pcf8523_write(client, PCF8523_REG_CONTROL1, value); |
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if (err < 0) |
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return err; |
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return 0; |
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} |
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static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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struct i2c_msg msg; |
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u8 regs[5]; |
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int err; |
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err = pcf8523_irq_enable(dev, 0); |
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if (err) |
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return err; |
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err = pcf8523_write(client, PCF8523_REG_CONTROL2, 0); |
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if (err < 0) |
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return err; |
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/* The alarm has no seconds, round up to nearest minute */ |
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if (tm->time.tm_sec) { |
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time64_t alarm_time = rtc_tm_to_time64(&tm->time); |
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alarm_time += 60 - tm->time.tm_sec; |
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rtc_time64_to_tm(alarm_time, &tm->time); |
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} |
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regs[0] = PCF8523_REG_MINUTE_ALARM; |
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regs[1] = bin2bcd(tm->time.tm_min); |
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regs[2] = bin2bcd(tm->time.tm_hour); |
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regs[3] = bin2bcd(tm->time.tm_mday); |
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regs[4] = ALARM_DIS; |
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msg.addr = client->addr; |
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msg.flags = 0; |
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msg.len = sizeof(regs); |
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msg.buf = regs; |
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err = i2c_transfer(client->adapter, &msg, 1); |
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if (err < 0) |
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return err; |
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if (tm->enabled) |
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return pcf8523_irq_enable(dev, tm->enabled); |
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return 0; |
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} |
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#ifdef CONFIG_RTC_INTF_DEV |
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static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, |
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unsigned long arg) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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unsigned int flags = 0; |
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u8 value; |
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int ret; |
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switch (cmd) { |
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case RTC_VL_READ: |
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ret = pcf8523_voltage_low(client); |
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if (ret < 0) |
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return ret; |
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if (ret) |
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flags |= RTC_VL_BACKUP_LOW; |
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ret = pcf8523_read(client, PCF8523_REG_SECONDS, &value); |
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if (ret < 0) |
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return ret; |
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if (value & PCF8523_SECONDS_OS) |
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flags |= RTC_VL_DATA_INVALID; |
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return put_user(flags, (unsigned int __user *)arg); |
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default: |
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return -ENOIOCTLCMD; |
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} |
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} |
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#else |
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#define pcf8523_rtc_ioctl NULL |
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#endif |
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static int pcf8523_rtc_read_offset(struct device *dev, long *offset) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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int err; |
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u8 value; |
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s8 val; |
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err = pcf8523_read(client, PCF8523_REG_OFFSET, &value); |
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if (err < 0) |
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return err; |
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/* sign extend the 7-bit offset value */ |
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val = value << 1; |
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*offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1); |
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return 0; |
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} |
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static int pcf8523_rtc_set_offset(struct device *dev, long offset) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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long reg_m0, reg_m1; |
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u8 value; |
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reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L); |
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reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L); |
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if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset)) |
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value = reg_m0 & 0x7f; |
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else |
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value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE; |
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return pcf8523_write(client, PCF8523_REG_OFFSET, value); |
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} |
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static const struct rtc_class_ops pcf8523_rtc_ops = { |
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.read_time = pcf8523_rtc_read_time, |
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.set_time = pcf8523_rtc_set_time, |
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.read_alarm = pcf8523_rtc_read_alarm, |
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.set_alarm = pcf8523_rtc_set_alarm, |
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.alarm_irq_enable = pcf8523_irq_enable, |
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.ioctl = pcf8523_rtc_ioctl, |
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.read_offset = pcf8523_rtc_read_offset, |
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.set_offset = pcf8523_rtc_set_offset, |
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}; |
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static int pcf8523_probe(struct i2c_client *client, |
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const struct i2c_device_id *id) |
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{ |
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struct pcf8523 *pcf8523; |
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struct rtc_device *rtc; |
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bool wakeup_source = false; |
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int err; |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
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return -ENODEV; |
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pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL); |
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if (!pcf8523) |
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return -ENOMEM; |
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i2c_set_clientdata(client, pcf8523); |
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pcf8523->client = client; |
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err = pcf8523_load_capacitance(client); |
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if (err < 0) |
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dev_warn(&client->dev, "failed to set xtal load capacitance: %d", |
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err); |
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err = pcf8523_set_pm(client, 0); |
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if (err < 0) |
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return err; |
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rtc = devm_rtc_allocate_device(&client->dev); |
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if (IS_ERR(rtc)) |
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return PTR_ERR(rtc); |
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pcf8523->rtc = rtc; |
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rtc->ops = &pcf8523_rtc_ops; |
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rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; |
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rtc->range_max = RTC_TIMESTAMP_END_2099; |
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rtc->uie_unsupported = 1; |
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if (client->irq > 0) { |
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err = pcf8523_write(client, PCF8523_TMR_CLKOUT_CTRL, 0x38); |
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if (err < 0) |
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return err; |
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err = devm_request_threaded_irq(&client->dev, client->irq, |
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NULL, pcf8523_irq, |
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IRQF_SHARED | IRQF_ONESHOT | IRQF_TRIGGER_LOW, |
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dev_name(&rtc->dev), client); |
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if (err) |
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return err; |
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dev_pm_set_wake_irq(&client->dev, client->irq); |
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} |
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#ifdef CONFIG_OF |
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wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source"); |
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#endif |
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if (client->irq > 0 || wakeup_source) |
|
device_init_wakeup(&client->dev, true); |
|
|
|
return devm_rtc_register_device(rtc); |
|
} |
|
|
|
static const struct i2c_device_id pcf8523_id[] = { |
|
{ "pcf8523", 0 }, |
|
{ } |
|
}; |
|
MODULE_DEVICE_TABLE(i2c, pcf8523_id); |
|
|
|
#ifdef CONFIG_OF |
|
static const struct of_device_id pcf8523_of_match[] = { |
|
{ .compatible = "nxp,pcf8523" }, |
|
{ .compatible = "microcrystal,rv8523" }, |
|
{ } |
|
}; |
|
MODULE_DEVICE_TABLE(of, pcf8523_of_match); |
|
#endif |
|
|
|
static struct i2c_driver pcf8523_driver = { |
|
.driver = { |
|
.name = "rtc-pcf8523", |
|
.of_match_table = of_match_ptr(pcf8523_of_match), |
|
}, |
|
.probe = pcf8523_probe, |
|
.id_table = pcf8523_id, |
|
}; |
|
module_i2c_driver(pcf8523_driver); |
|
|
|
MODULE_AUTHOR("Thierry Reding <[email protected]>"); |
|
MODULE_DESCRIPTION("NXP PCF8523 RTC driver"); |
|
MODULE_LICENSE("GPL v2");
|
|
|