--- /dev/null
+/*
+ * Seiko Instruments S-35390A RTC Driver
+ *
+ * Copyright (c) 2007 Byron Bradley
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/i2c.h>
+#include <linux/bitrev.h>
+#include <linux/bcd.h>
+#include <linux/slab.h>
+
+#define S35390A_CMD_STATUS1 0
+#define S35390A_CMD_STATUS2 1
+#define S35390A_CMD_TIME1 2
+
+#define S35390A_BYTE_YEAR 0
+#define S35390A_BYTE_MONTH 1
+#define S35390A_BYTE_DAY 2
+#define S35390A_BYTE_WDAY 3
+#define S35390A_BYTE_HOURS 4
+#define S35390A_BYTE_MINS 5
+#define S35390A_BYTE_SECS 6
+
+#define S35390A_FLAG_POC 0x01
+#define S35390A_FLAG_BLD 0x02
+#define S35390A_FLAG_24H 0x40
+#define S35390A_FLAG_RESET 0x80
+#define S35390A_FLAG_TEST 0x01
+
+struct s35390a {
+ struct i2c_client *client[8];
+ struct rtc_device *rtc;
+ int twentyfourhour;
+};
+
+static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
+{
+ struct i2c_client *client = s35390a->client[reg];
+ struct i2c_msg msg[] = {
+ { client->addr, 0, len, buf },
+ };
+
+ if ((i2c_transfer(client->adapter, msg, 1)) != 1)
+ return -EIO;
+
+ return 0;
+}
+
+static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
+{
+ struct i2c_client *client = s35390a->client[reg];
+ struct i2c_msg msg[] = {
+ { client->addr, I2C_M_RD, len, buf },
+ };
+
+ if ((i2c_transfer(client->adapter, msg, 1)) != 1)
+ return -EIO;
+
+ return 0;
+}
+
+static int s35390a_reset(struct s35390a *s35390a)
+{
+ char buf[1];
+
+ if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0)
+ return -EIO;
+
+ if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD)))
+ return 0;
+
+ buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H);
+ buf[0] &= 0xf0;
+ return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
+}
+
+static int s35390a_disable_test_mode(struct s35390a *s35390a)
+{
+ char buf[1];
+
+ if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
+ return -EIO;
+
+ if (!(buf[0] & S35390A_FLAG_TEST))
+ return 0;
+
+ buf[0] &= ~S35390A_FLAG_TEST;
+ return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
+}
+
+static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
+{
+ if (s35390a->twentyfourhour)
+ return BIN2BCD(hour);
+
+ if (hour < 12)
+ return BIN2BCD(hour);
+
+ return 0x40 | BIN2BCD(hour - 12);
+}
+
+static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
+{
+ unsigned hour;
+
+ if (s35390a->twentyfourhour)
+ return BCD2BIN(reg & 0x3f);
+
+ hour = BCD2BIN(reg & 0x3f);
+ if (reg & 0x40)
+ hour += 12;
+
+ return hour;
+}
+
+static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ struct s35390a *s35390a = i2c_get_clientdata(client);
+ int i, err;
+ char buf[7];
+
+ dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
+ "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
+ tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
+ tm->tm_wday);
+
+ buf[S35390A_BYTE_YEAR] = BIN2BCD(tm->tm_year - 100);
+ buf[S35390A_BYTE_MONTH] = BIN2BCD(tm->tm_mon + 1);
+ buf[S35390A_BYTE_DAY] = BIN2BCD(tm->tm_mday);
+ buf[S35390A_BYTE_WDAY] = BIN2BCD(tm->tm_wday);
+ buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
+ buf[S35390A_BYTE_MINS] = BIN2BCD(tm->tm_min);
+ buf[S35390A_BYTE_SECS] = BIN2BCD(tm->tm_sec);
+
+ /* This chip expects the bits of each byte to be in reverse order */
+ for (i = 0; i < 7; ++i)
+ buf[i] = bitrev8(buf[i]);
+
+ err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
+
+ return err;
+}
+
+static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ struct s35390a *s35390a = i2c_get_clientdata(client);
+ char buf[7];
+ int i, err;
+
+ err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
+ if (err < 0)
+ return err;
+
+ /* This chip returns the bits of each byte in reverse order */
+ for (i = 0; i < 7; ++i)
+ buf[i] = bitrev8(buf[i]);
+
+ tm->tm_sec = BCD2BIN(buf[S35390A_BYTE_SECS]);
+ tm->tm_min = BCD2BIN(buf[S35390A_BYTE_MINS]);
+ tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
+ tm->tm_wday = BCD2BIN(buf[S35390A_BYTE_WDAY]);
+ tm->tm_mday = BCD2BIN(buf[S35390A_BYTE_DAY]);
+ tm->tm_mon = BCD2BIN(buf[S35390A_BYTE_MONTH]) - 1;
+ tm->tm_year = BCD2BIN(buf[S35390A_BYTE_YEAR]) + 100;
+
+ dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
+ "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
+ tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
+ tm->tm_wday);
+
+ return rtc_valid_tm(tm);
+}
+
+static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return s35390a_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return s35390a_set_datetime(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops s35390a_rtc_ops = {
+ .read_time = s35390a_rtc_read_time,
+ .set_time = s35390a_rtc_set_time,
+};
+
+static struct i2c_driver s35390a_driver;
+
+static int s35390a_probe(struct i2c_client *client)
+{
+ int err;
+ unsigned int i;
+ struct s35390a *s35390a;
+ struct rtc_time tm;
+ char buf[1];
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ err = -ENODEV;
+ goto exit;
+ }
+
+ s35390a = kzalloc(sizeof(struct s35390a), GFP_KERNEL);
+ if (!s35390a) {
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ s35390a->client[0] = client;
+ i2c_set_clientdata(client, s35390a);
+
+ /* This chip uses multiple addresses, use dummy devices for them */
+ for (i = 1; i < 8; ++i) {
+ s35390a->client[i] = i2c_new_dummy(client->adapter,
+ client->addr + i, "rtc-s35390a");
+ if (!s35390a->client[i]) {
+ dev_err(&client->dev, "Address %02x unavailable\n",
+ client->addr + i);
+ err = -EBUSY;
+ goto exit_dummy;
+ }
+ }
+
+ err = s35390a_reset(s35390a);
+ if (err < 0) {
+ dev_err(&client->dev, "error resetting chip\n");
+ goto exit_dummy;
+ }
+
+ err = s35390a_disable_test_mode(s35390a);
+ if (err < 0) {
+ dev_err(&client->dev, "error disabling test mode\n");
+ goto exit_dummy;
+ }
+
+ err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
+ if (err < 0) {
+ dev_err(&client->dev, "error checking 12/24 hour mode\n");
+ goto exit_dummy;
+ }
+ if (buf[0] & S35390A_FLAG_24H)
+ s35390a->twentyfourhour = 1;
+ else
+ s35390a->twentyfourhour = 0;
+
+ if (s35390a_get_datetime(client, &tm) < 0)
+ dev_warn(&client->dev, "clock needs to be set\n");
+
+ s35390a->rtc = rtc_device_register(s35390a_driver.driver.name,
+ &client->dev, &s35390a_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(s35390a->rtc)) {
+ err = PTR_ERR(s35390a->rtc);
+ goto exit_dummy;
+ }
+ return 0;
+
+exit_dummy:
+ for (i = 1; i < 8; ++i)
+ if (s35390a->client[i])
+ i2c_unregister_device(s35390a->client[i]);
+ kfree(s35390a);
+ i2c_set_clientdata(client, NULL);
+
+exit:
+ return err;
+}
+
+static int s35390a_remove(struct i2c_client *client)
+{
+ unsigned int i;
+
+ struct s35390a *s35390a = i2c_get_clientdata(client);
+ for (i = 1; i < 8; ++i)
+ if (s35390a->client[i])
+ i2c_unregister_device(s35390a->client[i]);
+
+ rtc_device_unregister(s35390a->rtc);
+ kfree(s35390a);
+ i2c_set_clientdata(client, NULL);
+
+ return 0;
+}
+
+static struct i2c_driver s35390a_driver = {
+ .driver = {
+ .name = "rtc-s35390a",
+ },
+ .probe = s35390a_probe,
+ .remove = s35390a_remove,
+};
+
+static int __init s35390a_rtc_init(void)
+{
+ return i2c_add_driver(&s35390a_driver);
+}
+
+static void __exit s35390a_rtc_exit(void)
+{
+ i2c_del_driver(&s35390a_driver);
+}
+
+MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
+MODULE_DESCRIPTION("S35390A RTC driver");
+MODULE_LICENSE("GPL");
+
+module_init(s35390a_rtc_init);
+module_exit(s35390a_rtc_exit);
projects / GitHub / LineageOS / android_kernel_samsung_universal7580.git / commitdiff