// 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 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;
|
|
if (status1 & S35390A_FLAG_INT2)
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rtc_update_irq(s35390a->rtc, 1, RTC_AF);
|
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return rtc_register_device(s35390a->rtc);
|
}
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|
static struct i2c_driver s35390a_driver = {
|
.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 <byron.bbradley@gmail.com>");
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MODULE_DESCRIPTION("S35390A RTC driver");
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MODULE_LICENSE("GPL");
|
