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516 lines
13 KiB
516 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Seiko Instruments S-35390A RTC Driver |
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* |
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* Copyright (c) 2007 Byron Bradley |
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*/ |
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#include <linux/module.h> |
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#include <linux/rtc.h> |
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#include <linux/i2c.h> |
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#include <linux/bitrev.h> |
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#include <linux/bcd.h> |
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#include <linux/slab.h> |
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#include <linux/delay.h> |
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#define S35390A_CMD_STATUS1 0 |
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#define S35390A_CMD_STATUS2 1 |
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#define S35390A_CMD_TIME1 2 |
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#define S35390A_CMD_TIME2 3 |
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#define S35390A_CMD_INT2_REG1 5 |
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#define S35390A_BYTE_YEAR 0 |
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#define S35390A_BYTE_MONTH 1 |
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#define S35390A_BYTE_DAY 2 |
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#define S35390A_BYTE_WDAY 3 |
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#define S35390A_BYTE_HOURS 4 |
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#define S35390A_BYTE_MINS 5 |
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#define S35390A_BYTE_SECS 6 |
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#define S35390A_ALRM_BYTE_WDAY 0 |
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#define S35390A_ALRM_BYTE_HOURS 1 |
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#define S35390A_ALRM_BYTE_MINS 2 |
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/* flags for STATUS1 */ |
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#define S35390A_FLAG_POC BIT(0) |
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#define S35390A_FLAG_BLD BIT(1) |
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#define S35390A_FLAG_INT2 BIT(2) |
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#define S35390A_FLAG_24H BIT(6) |
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#define S35390A_FLAG_RESET BIT(7) |
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/* flag for STATUS2 */ |
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#define S35390A_FLAG_TEST BIT(0) |
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/* INT2 pin output mode */ |
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#define S35390A_INT2_MODE_MASK 0x0E |
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#define S35390A_INT2_MODE_NOINTR 0x00 |
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#define S35390A_INT2_MODE_ALARM BIT(1) /* INT2AE */ |
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#define S35390A_INT2_MODE_PMIN_EDG BIT(2) /* INT2ME */ |
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#define S35390A_INT2_MODE_FREQ BIT(3) /* INT2FE */ |
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#define S35390A_INT2_MODE_PMIN (BIT(3) | BIT(2)) /* INT2FE | INT2ME */ |
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static const struct i2c_device_id s35390a_id[] = { |
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{ "s35390a", 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, s35390a_id); |
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static const __maybe_unused struct of_device_id s35390a_of_match[] = { |
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{ .compatible = "s35390a" }, |
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{ .compatible = "sii,s35390a" }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, s35390a_of_match); |
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struct s35390a { |
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struct i2c_client *client[8]; |
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struct rtc_device *rtc; |
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int twentyfourhour; |
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}; |
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static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len) |
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{ |
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struct i2c_client *client = s35390a->client[reg]; |
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struct i2c_msg msg[] = { |
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{ |
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.addr = client->addr, |
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.len = len, |
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.buf = buf |
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}, |
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}; |
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if ((i2c_transfer(client->adapter, msg, 1)) != 1) |
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return -EIO; |
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return 0; |
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} |
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static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len) |
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{ |
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struct i2c_client *client = s35390a->client[reg]; |
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struct i2c_msg msg[] = { |
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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 = buf |
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}, |
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}; |
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if ((i2c_transfer(client->adapter, msg, 1)) != 1) |
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return -EIO; |
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return 0; |
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} |
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static int s35390a_init(struct s35390a *s35390a) |
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{ |
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u8 buf; |
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int ret; |
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unsigned initcount = 0; |
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/* |
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* At least one of POC and BLD are set, so reinitialise chip. Keeping |
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* this information in the hardware to know later that the time isn't |
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* valid is unfortunately not possible because POC and BLD are cleared |
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* on read. So the reset is best done now. |
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* |
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* The 24H bit is kept over reset, so set it already here. |
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*/ |
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initialize: |
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buf = S35390A_FLAG_RESET | S35390A_FLAG_24H; |
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ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1); |
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if (ret < 0) |
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return ret; |
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ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1); |
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if (ret < 0) |
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return ret; |
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if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) { |
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/* Try up to five times to reset the chip */ |
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if (initcount < 5) { |
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++initcount; |
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goto initialize; |
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} else |
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return -EIO; |
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} |
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return 1; |
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} |
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/* |
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* Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset. |
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* To keep the information if an irq is pending, pass the value read from |
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* STATUS1 to the caller. |
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*/ |
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static int s35390a_read_status(struct s35390a *s35390a, char *status1) |
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{ |
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int ret; |
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ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1); |
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if (ret < 0) |
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return ret; |
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if (*status1 & S35390A_FLAG_POC) { |
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/* |
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* Do not communicate for 0.5 seconds since the power-on |
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* detection circuit is in operation. |
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*/ |
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msleep(500); |
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return 1; |
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} else if (*status1 & S35390A_FLAG_BLD) |
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return 1; |
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/* |
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* If both POC and BLD are unset everything is fine. |
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*/ |
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return 0; |
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} |
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static int s35390a_disable_test_mode(struct s35390a *s35390a) |
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{ |
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char buf[1]; |
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if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0) |
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return -EIO; |
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if (!(buf[0] & S35390A_FLAG_TEST)) |
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return 0; |
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buf[0] &= ~S35390A_FLAG_TEST; |
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return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)); |
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} |
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static char s35390a_hr2reg(struct s35390a *s35390a, int hour) |
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{ |
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if (s35390a->twentyfourhour) |
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return bin2bcd(hour); |
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if (hour < 12) |
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return bin2bcd(hour); |
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return 0x40 | bin2bcd(hour - 12); |
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} |
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static int s35390a_reg2hr(struct s35390a *s35390a, char reg) |
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{ |
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unsigned hour; |
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if (s35390a->twentyfourhour) |
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return bcd2bin(reg & 0x3f); |
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hour = bcd2bin(reg & 0x3f); |
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if (reg & 0x40) |
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hour += 12; |
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return hour; |
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} |
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static int s35390a_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 s35390a *s35390a = i2c_get_clientdata(client); |
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int i, err; |
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char buf[7], status; |
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dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, " |
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"mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, |
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tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, |
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tm->tm_wday); |
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if (s35390a_read_status(s35390a, &status) == 1) |
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s35390a_init(s35390a); |
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buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100); |
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buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1); |
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buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday); |
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buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday); |
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buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour); |
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buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min); |
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buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec); |
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/* This chip expects the bits of each byte to be in reverse order */ |
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for (i = 0; i < 7; ++i) |
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buf[i] = bitrev8(buf[i]); |
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err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); |
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return err; |
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} |
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static int s35390a_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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struct s35390a *s35390a = i2c_get_clientdata(client); |
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char buf[7], status; |
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int i, err; |
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if (s35390a_read_status(s35390a, &status) == 1) |
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return -EINVAL; |
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err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); |
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if (err < 0) |
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return err; |
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/* This chip returns the bits of each byte in reverse order */ |
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for (i = 0; i < 7; ++i) |
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buf[i] = bitrev8(buf[i]); |
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tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]); |
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tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]); |
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tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]); |
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tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]); |
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tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]); |
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tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1; |
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tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100; |
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dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, " |
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"mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, |
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tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, |
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tm->tm_wday); |
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return 0; |
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} |
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static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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struct s35390a *s35390a = i2c_get_clientdata(client); |
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char buf[3], sts = 0; |
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int err, i; |
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dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\ |
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"mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec, |
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alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday, |
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alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday); |
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if (alm->time.tm_sec != 0) |
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dev_warn(&client->dev, "Alarms are only supported on a per minute basis!\n"); |
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/* disable interrupt (which deasserts the irq line) */ |
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err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); |
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if (err < 0) |
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return err; |
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/* clear pending interrupt (in STATUS1 only), if any */ |
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err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts)); |
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if (err < 0) |
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return err; |
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if (alm->enabled) |
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sts = S35390A_INT2_MODE_ALARM; |
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else |
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sts = S35390A_INT2_MODE_NOINTR; |
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/* set interupt mode*/ |
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err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); |
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if (err < 0) |
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return err; |
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if (alm->time.tm_wday != -1) |
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buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80; |
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else |
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buf[S35390A_ALRM_BYTE_WDAY] = 0; |
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buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a, |
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alm->time.tm_hour) | 0x80; |
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buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80; |
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if (alm->time.tm_hour >= 12) |
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buf[S35390A_ALRM_BYTE_HOURS] |= 0x40; |
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for (i = 0; i < 3; ++i) |
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buf[i] = bitrev8(buf[i]); |
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err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf, |
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sizeof(buf)); |
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return err; |
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} |
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static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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struct s35390a *s35390a = i2c_get_clientdata(client); |
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char buf[3], sts; |
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int i, err; |
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err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); |
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if (err < 0) |
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return err; |
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if ((sts & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) { |
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/* |
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* When the alarm isn't enabled, the register to configure |
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* the alarm time isn't accessible. |
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*/ |
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alm->enabled = 0; |
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return 0; |
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} else { |
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alm->enabled = 1; |
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} |
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err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf)); |
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if (err < 0) |
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return err; |
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/* This chip returns the bits of each byte in reverse order */ |
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for (i = 0; i < 3; ++i) |
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buf[i] = bitrev8(buf[i]); |
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/* |
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* B0 of the three matching registers is an enable flag. Iff it is set |
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* the configured value is used for matching. |
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*/ |
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if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80) |
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alm->time.tm_wday = |
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bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80); |
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if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80) |
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alm->time.tm_hour = |
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s35390a_reg2hr(s35390a, |
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buf[S35390A_ALRM_BYTE_HOURS] & ~0x80); |
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if (buf[S35390A_ALRM_BYTE_MINS] & 0x80) |
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alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80); |
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/* alarm triggers always at s=0 */ |
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alm->time.tm_sec = 0; |
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dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n", |
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__func__, alm->time.tm_min, alm->time.tm_hour, |
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alm->time.tm_wday); |
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return 0; |
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} |
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static int s35390a_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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struct s35390a *s35390a = i2c_get_clientdata(client); |
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char sts; |
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int err; |
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switch (cmd) { |
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case RTC_VL_READ: |
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/* s35390a_reset set lowvoltage flag and init RTC if needed */ |
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err = s35390a_read_status(s35390a, &sts); |
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if (err < 0) |
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return err; |
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if (copy_to_user((void __user *)arg, &err, sizeof(int))) |
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return -EFAULT; |
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break; |
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case RTC_VL_CLR: |
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/* update flag and clear register */ |
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err = s35390a_init(s35390a); |
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if (err < 0) |
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return err; |
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break; |
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default: |
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return -ENOIOCTLCMD; |
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} |
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return 0; |
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} |
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static const struct rtc_class_ops s35390a_rtc_ops = { |
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.read_time = s35390a_rtc_read_time, |
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.set_time = s35390a_rtc_set_time, |
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.set_alarm = s35390a_rtc_set_alarm, |
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.read_alarm = s35390a_rtc_read_alarm, |
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.ioctl = s35390a_rtc_ioctl, |
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}; |
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static int s35390a_probe(struct i2c_client *client, |
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const struct i2c_device_id *id) |
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{ |
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int err, err_read; |
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unsigned int i; |
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struct s35390a *s35390a; |
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char buf, status1; |
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struct device *dev = &client->dev; |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
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return -ENODEV; |
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s35390a = devm_kzalloc(dev, sizeof(struct s35390a), GFP_KERNEL); |
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if (!s35390a) |
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return -ENOMEM; |
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s35390a->client[0] = client; |
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i2c_set_clientdata(client, s35390a); |
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/* This chip uses multiple addresses, use dummy devices for them */ |
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for (i = 1; i < 8; ++i) { |
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s35390a->client[i] = devm_i2c_new_dummy_device(dev, |
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client->adapter, |
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client->addr + i); |
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if (IS_ERR(s35390a->client[i])) { |
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dev_err(dev, "Address %02x unavailable\n", |
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client->addr + i); |
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return PTR_ERR(s35390a->client[i]); |
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} |
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} |
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s35390a->rtc = devm_rtc_allocate_device(dev); |
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if (IS_ERR(s35390a->rtc)) |
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return PTR_ERR(s35390a->rtc); |
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err_read = s35390a_read_status(s35390a, &status1); |
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if (err_read < 0) { |
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dev_err(dev, "error resetting chip\n"); |
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return err_read; |
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} |
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if (status1 & S35390A_FLAG_24H) |
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s35390a->twentyfourhour = 1; |
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else |
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s35390a->twentyfourhour = 0; |
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if (status1 & S35390A_FLAG_INT2) { |
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/* disable alarm (and maybe test mode) */ |
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buf = 0; |
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err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1); |
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if (err < 0) { |
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dev_err(dev, "error disabling alarm"); |
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return err; |
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} |
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} else { |
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err = s35390a_disable_test_mode(s35390a); |
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if (err < 0) { |
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dev_err(dev, "error disabling test mode\n"); |
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return err; |
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} |
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} |
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device_set_wakeup_capable(dev, 1); |
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s35390a->rtc->ops = &s35390a_rtc_ops; |
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s35390a->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; |
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s35390a->rtc->range_max = RTC_TIMESTAMP_END_2099; |
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/* supports per-minute alarms only, therefore set uie_unsupported */ |
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s35390a->rtc->uie_unsupported = 1; |
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if (status1 & S35390A_FLAG_INT2) |
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rtc_update_irq(s35390a->rtc, 1, RTC_AF); |
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return devm_rtc_register_device(s35390a->rtc); |
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} |
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static struct i2c_driver s35390a_driver = { |
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.driver = { |
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.name = "rtc-s35390a", |
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.of_match_table = of_match_ptr(s35390a_of_match), |
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}, |
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.probe = s35390a_probe, |
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.id_table = s35390a_id, |
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}; |
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module_i2c_driver(s35390a_driver); |
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MODULE_AUTHOR("Byron Bradley <[email protected]>"); |
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MODULE_DESCRIPTION("S35390A RTC driver"); |
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MODULE_LICENSE("GPL");
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