--- /dev/null
+/*
+ * An I2C driver for the Intersil ISL 12022
+ *
+ * Author: Roman Fietze <roman.fietze@telemotive.de>
+ *
+ * Based on the Philips PCF8563 RTC
+ * by Alessandro Zummo <a.zummo@towertech.it>.
+ *
+ * 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.
+ */
+
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+
+#define DRV_VERSION "0.1"
+
+/* ISL register offsets */
+#define ISL12022_REG_SC 0x00
+#define ISL12022_REG_MN 0x01
+#define ISL12022_REG_HR 0x02
+#define ISL12022_REG_DT 0x03
+#define ISL12022_REG_MO 0x04
+#define ISL12022_REG_YR 0x05
+#define ISL12022_REG_DW 0x06
+
+#define ISL12022_REG_SR 0x07
+#define ISL12022_REG_INT 0x08
+
+/* ISL register bits */
+#define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
+
+#define ISL12022_SR_LBAT85 (1 << 2)
+#define ISL12022_SR_LBAT75 (1 << 1)
+
+#define ISL12022_INT_WRTC (1 << 6)
+
+
+static struct i2c_driver isl12022_driver;
+
+struct isl12022 {
+ struct rtc_device *rtc;
+
+ bool write_enabled; /* true if write enable is set */
+};
+
+
+static int isl12022_read_regs(struct i2c_client *client, uint8_t reg,
+ uint8_t *data, size_t n)
+{
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = data
+ }, /* setup read ptr */
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = n,
+ .buf = data
+ }
+ };
+
+ int ret;
+
+ data[0] = reg;
+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+ if (ret != ARRAY_SIZE(msgs)) {
+ dev_err(&client->dev, "%s: read error, ret=%d\n",
+ __func__, ret);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+
+static int isl12022_write_reg(struct i2c_client *client,
+ uint8_t reg, uint8_t val)
+{
+ uint8_t data[2] = { reg, val };
+ int err;
+
+ err = i2c_master_send(client, data, sizeof(data));
+ if (err != sizeof(data)) {
+ dev_err(&client->dev,
+ "%s: err=%d addr=%02x, data=%02x\n",
+ __func__, err, data[0], data[1]);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+
+/*
+ * In the routines that deal directly with the isl12022 hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
+ */
+static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ uint8_t buf[ISL12022_REG_INT + 1];
+ int ret;
+
+ ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf));
+ if (ret)
+ return ret;
+
+ if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
+ dev_warn(&client->dev,
+ "voltage dropped below %u%%, "
+ "date and time is not reliable.\n",
+ buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
+ }
+
+ dev_dbg(&client->dev,
+ "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
+ "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
+ "sr=%02x, int=%02x",
+ __func__,
+ buf[ISL12022_REG_SC],
+ buf[ISL12022_REG_MN],
+ buf[ISL12022_REG_HR],
+ buf[ISL12022_REG_DT],
+ buf[ISL12022_REG_MO],
+ buf[ISL12022_REG_YR],
+ buf[ISL12022_REG_DW],
+ buf[ISL12022_REG_SR],
+ buf[ISL12022_REG_INT]);
+
+ tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
+ tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
+ tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
+ tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
+ tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
+ tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
+ tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
+
+ 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);
+
+ /* The clock can give out invalid datetime, but we cannot return
+ * -EINVAL otherwise hwclock will refuse to set the time on bootup. */
+ if (rtc_valid_tm(tm) < 0)
+ dev_err(&client->dev, "retrieved date and time is invalid.\n");
+
+ return 0;
+}
+
+static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ struct isl12022 *isl12022 = i2c_get_clientdata(client);
+ size_t i;
+ int ret;
+ uint8_t buf[ISL12022_REG_DW + 1];
+
+ 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);
+
+ if (!isl12022->write_enabled) {
+
+ ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1);
+ if (ret)
+ return ret;
+
+ /* Check if WRTC (write rtc enable) is set factory default is
+ * 0 (not set) */
+ if (!(buf[0] & ISL12022_INT_WRTC)) {
+ dev_info(&client->dev,
+ "init write enable and 24 hour format\n");
+
+ /* Set the write enable bit. */
+ ret = isl12022_write_reg(client,
+ ISL12022_REG_INT,
+ buf[0] | ISL12022_INT_WRTC);
+ if (ret)
+ return ret;
+
+ /* Write to any RTC register to start RTC, we use the
+ * HR register, setting the MIL bit to use the 24 hour
+ * format. */
+ ret = isl12022_read_regs(client, ISL12022_REG_HR,
+ buf, 1);
+ if (ret)
+ return ret;
+
+ ret = isl12022_write_reg(client,
+ ISL12022_REG_HR,
+ buf[0] | ISL12022_HR_MIL);
+ if (ret)
+ return ret;
+ }
+
+ isl12022->write_enabled = 1;
+ }
+
+ /* hours, minutes and seconds */
+ buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
+ buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
+ buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour);
+
+ buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
+
+ /* month, 1 - 12 */
+ buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
+
+ /* year and century */
+ buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
+
+ buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
+
+ /* write register's data */
+ for (i = 0; i < ARRAY_SIZE(buf); i++) {
+ ret = isl12022_write_reg(client, ISL12022_REG_SC + i,
+ buf[ISL12022_REG_SC + i]);
+ if (ret)
+ return -EIO;
+ };
+
+ return 0;
+}
+
+static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return isl12022_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return isl12022_set_datetime(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops isl12022_rtc_ops = {
+ .read_time = isl12022_rtc_read_time,
+ .set_time = isl12022_rtc_set_time,
+};
+
+static int isl12022_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct isl12022 *isl12022;
+
+ int ret = 0;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ isl12022 = kzalloc(sizeof(struct isl12022), GFP_KERNEL);
+ if (!isl12022)
+ return -ENOMEM;
+
+ dev_dbg(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+ i2c_set_clientdata(client, isl12022);
+
+ isl12022->rtc = rtc_device_register(isl12022_driver.driver.name,
+ &client->dev,
+ &isl12022_rtc_ops,
+ THIS_MODULE);
+
+ if (IS_ERR(isl12022->rtc)) {
+ ret = PTR_ERR(isl12022->rtc);
+ goto exit_kfree;
+ }
+
+ return 0;
+
+exit_kfree:
+ kfree(isl12022);
+
+ return ret;
+}
+
+static int isl12022_remove(struct i2c_client *client)
+{
+ struct isl12022 *isl12022 = i2c_get_clientdata(client);
+
+ rtc_device_unregister(isl12022->rtc);
+ kfree(isl12022);
+
+ return 0;
+}
+
+static const struct i2c_device_id isl12022_id[] = {
+ { "isl12022", 0 },
+ { "rtc8564", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, isl12022_id);
+
+static struct i2c_driver isl12022_driver = {
+ .driver = {
+ .name = "rtc-isl12022",
+ },
+ .probe = isl12022_probe,
+ .remove = isl12022_remove,
+ .id_table = isl12022_id,
+};
+
+static int __init isl12022_init(void)
+{
+ return i2c_add_driver(&isl12022_driver);
+}
+
+static void __exit isl12022_exit(void)
+{
+ i2c_del_driver(&isl12022_driver);
+}
+
+module_init(isl12022_init);
+module_exit(isl12022_exit);
+
+MODULE_AUTHOR("roman.fietze@telemotive.de");
+MODULE_DESCRIPTION("ISL 12022 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / commitdiff