--- /dev/null
+/*
+ * An I2C driver for the Epson RX8581 RTC
+ *
+ * Author: Martyn Welch <martyn.welch@ge.com>
+ * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
+ * Copyright 2005-06 Tower Technologies
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/log2.h>
+
+#define DRV_VERSION "0.1"
+
+#define RX8581_REG_SC 0x00 /* Second in BCD */
+#define RX8581_REG_MN 0x01 /* Minute in BCD */
+#define RX8581_REG_HR 0x02 /* Hour in BCD */
+#define RX8581_REG_DW 0x03 /* Day of Week */
+#define RX8581_REG_DM 0x04 /* Day of Month in BCD */
+#define RX8581_REG_MO 0x05 /* Month in BCD */
+#define RX8581_REG_YR 0x06 /* Year in BCD */
+#define RX8581_REG_RAM 0x07 /* RAM */
+#define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/
+#define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */
+#define RX8581_REG_ADM 0x0A
+#define RX8581_REG_ADW 0x0A
+#define RX8581_REG_TMR0 0x0B
+#define RX8581_REG_TMR1 0x0C
+#define RX8581_REG_EXT 0x0D /* Extension Register */
+#define RX8581_REG_FLAG 0x0E /* Flag Register */
+#define RX8581_REG_CTRL 0x0F /* Control Register */
+
+
+/* Flag Register bit definitions */
+#define RX8581_FLAG_UF 0x20 /* Update */
+#define RX8581_FLAG_TF 0x10 /* Timer */
+#define RX8581_FLAG_AF 0x08 /* Alarm */
+#define RX8581_FLAG_VLF 0x02 /* Voltage Low */
+
+/* Control Register bit definitions */
+#define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */
+#define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */
+#define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */
+#define RX8581_CTRL_STOP 0x02 /* STOP bit */
+#define RX8581_CTRL_RESET 0x01 /* RESET bit */
+
+struct rx8581 {
+ struct i2c_client *client;
+ struct rtc_device *rtc;
+ s32 (*read_block_data)(const struct i2c_client *client, u8 command,
+ u8 length, u8 *values);
+ s32 (*write_block_data)(const struct i2c_client *client, u8 command,
+ u8 length, const u8 *values);
+};
+
+static struct i2c_driver rx8581_driver;
+
+static int rx8581_read_block_data(const struct i2c_client *client, u8 command,
+ u8 length, u8 *values)
+{
+ s32 i, data;
+
+ for (i = 0; i < length; i++) {
+ data = i2c_smbus_read_byte_data(client, command + i);
+ if (data < 0)
+ return data;
+ values[i] = data;
+ }
+ return i;
+}
+
+static int rx8581_write_block_data(const struct i2c_client *client, u8 command,
+ u8 length, const u8 *values)
+{
+ s32 i, ret;
+
+ for (i = 0; i < length; i++) {
+ ret = i2c_smbus_write_byte_data(client, command + i,
+ values[i]);
+ if (ret < 0)
+ return ret;
+ }
+ return length;
+}
+
+/*
+ * In the routines that deal directly with the rx8581 hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
+ */
+static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ unsigned char date[7];
+ int data, err;
+ struct rx8581 *rx8581 = i2c_get_clientdata(client);
+
+ /* First we ensure that the "update flag" is not set, we read the
+ * time and date then re-read the "update flag". If the update flag
+ * has been set, we know that the time has changed during the read so
+ * we repeat the whole process again.
+ */
+ data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
+ if (data < 0) {
+ dev_err(&client->dev, "Unable to read device flags\n");
+ return -EIO;
+ }
+
+ do {
+ /* If update flag set, clear it */
+ if (data & RX8581_FLAG_UF) {
+ err = i2c_smbus_write_byte_data(client,
+ RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF));
+ if (err != 0) {
+ dev_err(&client->dev, "Unable to write device flags\n");
+ return -EIO;
+ }
+ }
+
+ /* Now read time and date */
+ err = rx8581->read_block_data(client, RX8581_REG_SC,
+ 7, date);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to read date\n");
+ return -EIO;
+ }
+
+ /* Check flag register */
+ data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
+ if (data < 0) {
+ dev_err(&client->dev, "Unable to read device flags\n");
+ return -EIO;
+ }
+ } while (data & RX8581_FLAG_UF);
+
+ if (data & RX8581_FLAG_VLF)
+ dev_info(&client->dev,
+ "low voltage detected, date/time is not reliable.\n");
+
+ dev_dbg(&client->dev,
+ "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
+ "wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
+ __func__,
+ date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
+
+ tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
+ tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
+ tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
+ tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
+ tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
+ tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
+ tm->tm_year = bcd2bin(date[RX8581_REG_YR]);
+ if (tm->tm_year < 70)
+ tm->tm_year += 100; /* assume we are in 1970...2069 */
+
+
+ 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);
+
+ err = rtc_valid_tm(tm);
+ if (err < 0)
+ dev_err(&client->dev, "retrieved date/time is not valid.\n");
+
+ return err;
+}
+
+static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ int data, err;
+ unsigned char buf[7];
+ struct rx8581 *rx8581 = i2c_get_clientdata(client);
+
+ dev_dbg(&client->dev, "%s: 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);
+
+ /* hours, minutes and seconds */
+ buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
+ buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
+ buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
+
+ buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
+
+ /* month, 1 - 12 */
+ buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
+
+ /* year and century */
+ buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100);
+ buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
+
+ /* Stop the clock */
+ data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
+ if (data < 0) {
+ dev_err(&client->dev, "Unable to read control register\n");
+ return -EIO;
+ }
+
+ err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
+ (data | RX8581_CTRL_STOP));
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write control register\n");
+ return -EIO;
+ }
+
+ /* write register's data */
+ err = rx8581->write_block_data(client, RX8581_REG_SC, 7, buf);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write to date registers\n");
+ return -EIO;
+ }
+
+ /* get VLF and clear it */
+ data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
+ if (data < 0) {
+ dev_err(&client->dev, "Unable to read flag register\n");
+ return -EIO;
+ }
+
+ err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG,
+ (data & ~(RX8581_FLAG_VLF)));
+ if (err != 0) {
+ dev_err(&client->dev, "Unable to write flag register\n");
+ return -EIO;
+ }
+
+ /* Restart the clock */
+ data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
+ if (data < 0) {
+ dev_err(&client->dev, "Unable to read control register\n");
+ return -EIO;
+ }
+
+ err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
+ (data & ~(RX8581_CTRL_STOP)));
+ if (err != 0) {
+ dev_err(&client->dev, "Unable to write control register\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return rx8581_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return rx8581_set_datetime(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops rx8581_rtc_ops = {
+ .read_time = rx8581_rtc_read_time,
+ .set_time = rx8581_rtc_set_time,
+};
+
+static int rx8581_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct rx8581 *rx8581;
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)
+ && !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
+ return -EIO;
+
+ rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
+ if (!rx8581)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, rx8581);
+ rx8581->client = client;
+
+ if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
+ rx8581->read_block_data = i2c_smbus_read_i2c_block_data;
+ rx8581->write_block_data = i2c_smbus_write_i2c_block_data;
+ } else {
+ rx8581->read_block_data = rx8581_read_block_data;
+ rx8581->write_block_data = rx8581_write_block_data;
+ }
+
+ dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+ rx8581->rtc = devm_rtc_device_register(&client->dev,
+ rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rx8581->rtc)) {
+ dev_err(&client->dev,
+ "unable to register the class device\n");
+ return PTR_ERR(rx8581->rtc);
+ }
+
+ return 0;
+}
+
+static const struct i2c_device_id rx8581_id[] = {
+ { "rx8581", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, rx8581_id);
+
+static struct i2c_driver rx8581_driver = {
+ .driver = {
+ .name = "rtc-rx8581",
+ .owner = THIS_MODULE,
+ },
+ .probe = rx8581_probe,
+ .id_table = rx8581_id,
+};
+
+module_i2c_driver(rx8581_driver);
+
+MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
+MODULE_DESCRIPTION("Epson RX-8581 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
Code Review / kvmfornfv.git / blobdiff