[PATCH] RTC subsystem: X1205 driver
A port of the existing x1205 driver under the new RTC subsystem.
It is actually under test within the NSLU2 project
(http://www.nslu2-linux.org) and it is working quite well.
It is the first driver under this new subsystem and should be used as a guide
to port other drivers.
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/rtc/rtc-x1205.c b/drivers/rtc/rtc-x1205.c
new file mode 100644
index 0000000..621d17a
--- /dev/null
+++ b/drivers/rtc/rtc-x1205.c
@@ -0,0 +1,619 @@
+/*
+ * An i2c driver for the Xicor/Intersil X1205 RTC
+ * Copyright 2004 Karen Spearel
+ * Copyright 2005 Alessandro Zummo
+ *
+ * please send all reports to:
+ * Karen Spearel <kas111 at gmail dot com>
+ * Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on a lot of other RTC drivers.
+ *
+ * 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/delay.h>
+
+#define DRV_VERSION "1.0.6"
+
+/* Addresses to scan: none. This chip is located at
+ * 0x6f and uses a two bytes register addressing.
+ * Two bytes need to be written to read a single register,
+ * while most other chips just require one and take the second
+ * one as the data to be written. To prevent corrupting
+ * unknown chips, the user must explicitely set the probe parameter.
+ */
+
+static unsigned short normal_i2c[] = { I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD;
+
+/* offsets into CCR area */
+
+#define CCR_SEC 0
+#define CCR_MIN 1
+#define CCR_HOUR 2
+#define CCR_MDAY 3
+#define CCR_MONTH 4
+#define CCR_YEAR 5
+#define CCR_WDAY 6
+#define CCR_Y2K 7
+
+#define X1205_REG_SR 0x3F /* status register */
+#define X1205_REG_Y2K 0x37
+#define X1205_REG_DW 0x36
+#define X1205_REG_YR 0x35
+#define X1205_REG_MO 0x34
+#define X1205_REG_DT 0x33
+#define X1205_REG_HR 0x32
+#define X1205_REG_MN 0x31
+#define X1205_REG_SC 0x30
+#define X1205_REG_DTR 0x13
+#define X1205_REG_ATR 0x12
+#define X1205_REG_INT 0x11
+#define X1205_REG_0 0x10
+#define X1205_REG_Y2K1 0x0F
+#define X1205_REG_DWA1 0x0E
+#define X1205_REG_YRA1 0x0D
+#define X1205_REG_MOA1 0x0C
+#define X1205_REG_DTA1 0x0B
+#define X1205_REG_HRA1 0x0A
+#define X1205_REG_MNA1 0x09
+#define X1205_REG_SCA1 0x08
+#define X1205_REG_Y2K0 0x07
+#define X1205_REG_DWA0 0x06
+#define X1205_REG_YRA0 0x05
+#define X1205_REG_MOA0 0x04
+#define X1205_REG_DTA0 0x03
+#define X1205_REG_HRA0 0x02
+#define X1205_REG_MNA0 0x01
+#define X1205_REG_SCA0 0x00
+
+#define X1205_CCR_BASE 0x30 /* Base address of CCR */
+#define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */
+
+#define X1205_SR_RTCF 0x01 /* Clock failure */
+#define X1205_SR_WEL 0x02 /* Write Enable Latch */
+#define X1205_SR_RWEL 0x04 /* Register Write Enable */
+
+#define X1205_DTR_DTR0 0x01
+#define X1205_DTR_DTR1 0x02
+#define X1205_DTR_DTR2 0x04
+
+#define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */
+
+/* Prototypes */
+static int x1205_attach(struct i2c_adapter *adapter);
+static int x1205_detach(struct i2c_client *client);
+static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
+
+static struct i2c_driver x1205_driver = {
+ .driver = {
+ .name = "x1205",
+ },
+ .id = I2C_DRIVERID_X1205,
+ .attach_adapter = &x1205_attach,
+ .detach_client = &x1205_detach,
+};
+
+/*
+ * In the routines that deal directly with the x1205 hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
+ * Epoch is initialized as 2000. Time is set to UTC.
+ */
+static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
+ unsigned char reg_base)
+{
+ unsigned char dt_addr[2] = { 0, reg_base };
+
+ unsigned char buf[8];
+
+ struct i2c_msg msgs[] = {
+ { client->addr, 0, 2, dt_addr }, /* setup read ptr */
+ { client->addr, I2C_M_RD, 8, buf }, /* read date */
+ };
+
+ /* read date registers */
+ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+ return -EIO;
+ }
+
+ dev_dbg(&client->dev,
+ "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
+ "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
+ __FUNCTION__,
+ buf[0], buf[1], buf[2], buf[3],
+ buf[4], buf[5], buf[6], buf[7]);
+
+ tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
+ tm->tm_min = BCD2BIN(buf[CCR_MIN]);
+ tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
+ tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
+ tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
+ tm->tm_year = BCD2BIN(buf[CCR_YEAR])
+ + (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;
+ tm->tm_wday = buf[CCR_WDAY];
+
+ dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
+ "mday=%d, mon=%d, year=%d, wday=%d\n",
+ __FUNCTION__,
+ tm->tm_sec, tm->tm_min, tm->tm_hour,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+ return 0;
+}
+
+static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
+{
+ static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
+
+ struct i2c_msg msgs[] = {
+ { client->addr, 0, 2, sr_addr }, /* setup read ptr */
+ { client->addr, I2C_M_RD, 1, sr }, /* read status */
+ };
+
+ /* read status register */
+ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
+ int datetoo, u8 reg_base)
+{
+ int i, xfer;
+ unsigned char buf[8];
+
+ static const unsigned char wel[3] = { 0, X1205_REG_SR,
+ X1205_SR_WEL };
+
+ static const unsigned char rwel[3] = { 0, X1205_REG_SR,
+ X1205_SR_WEL | X1205_SR_RWEL };
+
+ static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
+
+ dev_dbg(&client->dev,
+ "%s: secs=%d, mins=%d, hours=%d\n",
+ __FUNCTION__,
+ tm->tm_sec, tm->tm_min, tm->tm_hour);
+
+ buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
+ buf[CCR_MIN] = BIN2BCD(tm->tm_min);
+
+ /* set hour and 24hr bit */
+ buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
+
+ /* should we also set the date? */
+ if (datetoo) {
+ dev_dbg(&client->dev,
+ "%s: mday=%d, mon=%d, year=%d, wday=%d\n",
+ __FUNCTION__,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+ buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
+
+ /* month, 1 - 12 */
+ buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);
+
+ /* year, since the rtc epoch*/
+ buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);
+ buf[CCR_WDAY] = tm->tm_wday & 0x07;
+ buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);
+ }
+
+ /* this sequence is required to unlock the chip */
+ if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
+ dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer);
+ return -EIO;
+ }
+
+ if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
+ dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer);
+ return -EIO;
+ }
+
+ /* write register's data */
+ for (i = 0; i < (datetoo ? 8 : 3); i++) {
+ unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
+
+ xfer = i2c_master_send(client, rdata, 3);
+ if (xfer != 3) {
+ dev_err(&client->dev,
+ "%s: xfer=%d addr=%02x, data=%02x\n",
+ __FUNCTION__,
+ xfer, rdata[1], rdata[2]);
+ return -EIO;
+ }
+ };
+
+ /* disable further writes */
+ if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
+ dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int x1205_fix_osc(struct i2c_client *client)
+{
+ int err;
+ struct rtc_time tm;
+
+ tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
+
+ if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)
+ dev_err(&client->dev,
+ "unable to restart the oscillator\n");
+
+ return err;
+}
+
+static int x1205_get_dtrim(struct i2c_client *client, int *trim)
+{
+ unsigned char dtr;
+ static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
+
+ struct i2c_msg msgs[] = {
+ { client->addr, 0, 2, dtr_addr }, /* setup read ptr */
+ { client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */
+ };
+
+ /* read dtr register */
+ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+ return -EIO;
+ }
+
+ dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr);
+
+ *trim = 0;
+
+ if (dtr & X1205_DTR_DTR0)
+ *trim += 20;
+
+ if (dtr & X1205_DTR_DTR1)
+ *trim += 10;
+
+ if (dtr & X1205_DTR_DTR2)
+ *trim = -*trim;
+
+ return 0;
+}
+
+static int x1205_get_atrim(struct i2c_client *client, int *trim)
+{
+ s8 atr;
+ static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
+
+ struct i2c_msg msgs[] = {
+ { client->addr, 0, 2, atr_addr }, /* setup read ptr */
+ { client->addr, I2C_M_RD, 1, &atr }, /* read atr */
+ };
+
+ /* read atr register */
+ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+ return -EIO;
+ }
+
+ dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr);
+
+ /* atr is a two's complement value on 6 bits,
+ * perform sign extension. The formula is
+ * Catr = (atr * 0.25pF) + 11.00pF.
+ */
+ if (atr & 0x20)
+ atr |= 0xC0;
+
+ dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr);
+
+ *trim = (atr * 250) + 11000;
+
+ dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim);
+
+ return 0;
+}
+
+struct x1205_limit
+{
+ unsigned char reg, mask, min, max;
+};
+
+static int x1205_validate_client(struct i2c_client *client)
+{
+ int i, xfer;
+
+ /* Probe array. We will read the register at the specified
+ * address and check if the given bits are zero.
+ */
+ static const unsigned char probe_zero_pattern[] = {
+ /* register, mask */
+ X1205_REG_SR, 0x18,
+ X1205_REG_DTR, 0xF8,
+ X1205_REG_ATR, 0xC0,
+ X1205_REG_INT, 0x18,
+ X1205_REG_0, 0xFF,
+ };
+
+ static const struct x1205_limit probe_limits_pattern[] = {
+ /* register, mask, min, max */
+ { X1205_REG_Y2K, 0xFF, 19, 20 },
+ { X1205_REG_DW, 0xFF, 0, 6 },
+ { X1205_REG_YR, 0xFF, 0, 99 },
+ { X1205_REG_MO, 0xFF, 0, 12 },
+ { X1205_REG_DT, 0xFF, 0, 31 },
+ { X1205_REG_HR, 0x7F, 0, 23 },
+ { X1205_REG_MN, 0xFF, 0, 59 },
+ { X1205_REG_SC, 0xFF, 0, 59 },
+ { X1205_REG_Y2K1, 0xFF, 19, 20 },
+ { X1205_REG_Y2K0, 0xFF, 19, 20 },
+ };
+
+ /* check that registers have bits a 0 where expected */
+ for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
+ unsigned char buf;
+
+ unsigned char addr[2] = { 0, probe_zero_pattern[i] };
+
+ struct i2c_msg msgs[2] = {
+ { client->addr, 0, 2, addr },
+ { client->addr, I2C_M_RD, 1, &buf },
+ };
+
+ if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
+ dev_err(&client->adapter->dev,
+ "%s: could not read register %x\n",
+ __FUNCTION__, probe_zero_pattern[i]);
+
+ return -EIO;
+ }
+
+ if ((buf & probe_zero_pattern[i+1]) != 0) {
+ dev_err(&client->adapter->dev,
+ "%s: register=%02x, zero pattern=%d, value=%x\n",
+ __FUNCTION__, probe_zero_pattern[i], i, buf);
+
+ return -ENODEV;
+ }
+ }
+
+ /* check limits (only registers with bcd values) */
+ for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
+ unsigned char reg, value;
+
+ unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
+
+ struct i2c_msg msgs[2] = {
+ { client->addr, 0, 2, addr },
+ { client->addr, I2C_M_RD, 1, ® },
+ };
+
+ if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
+ dev_err(&client->adapter->dev,
+ "%s: could not read register %x\n",
+ __FUNCTION__, probe_limits_pattern[i].reg);
+
+ return -EIO;
+ }
+
+ value = BCD2BIN(reg & probe_limits_pattern[i].mask);
+
+ if (value > probe_limits_pattern[i].max ||
+ value < probe_limits_pattern[i].min) {
+ dev_dbg(&client->adapter->dev,
+ "%s: register=%x, lim pattern=%d, value=%d\n",
+ __FUNCTION__, probe_limits_pattern[i].reg,
+ i, value);
+
+ return -ENODEV;
+ }
+ }
+
+ return 0;
+}
+
+static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ return x1205_get_datetime(to_i2c_client(dev),
+ &alrm->time, X1205_ALM0_BASE);
+}
+
+static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ return x1205_set_datetime(to_i2c_client(dev),
+ &alrm->time, 1, X1205_ALM0_BASE);
+}
+
+static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return x1205_get_datetime(to_i2c_client(dev),
+ tm, X1205_CCR_BASE);
+}
+
+static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return x1205_set_datetime(to_i2c_client(dev),
+ tm, 1, X1205_CCR_BASE);
+}
+
+static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ int err, dtrim, atrim;
+
+ seq_printf(seq, "24hr\t\t: yes\n");
+
+ if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
+ seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
+
+ if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
+ seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
+ atrim / 1000, atrim % 1000);
+ return 0;
+}
+
+static struct rtc_class_ops x1205_rtc_ops = {
+ .proc = x1205_rtc_proc,
+ .read_time = x1205_rtc_read_time,
+ .set_time = x1205_rtc_set_time,
+ .read_alarm = x1205_rtc_read_alarm,
+ .set_alarm = x1205_rtc_set_alarm,
+};
+
+static ssize_t x1205_sysfs_show_atrim(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int atrim;
+
+ if (x1205_get_atrim(to_i2c_client(dev), &atrim) == 0)
+ return sprintf(buf, "%d.%02d pF\n",
+ atrim / 1000, atrim % 1000);
+ return 0;
+}
+static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
+
+static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int dtrim;
+
+ if (x1205_get_dtrim(to_i2c_client(dev), &dtrim) == 0)
+ return sprintf(buf, "%d ppm\n", dtrim);
+
+ return 0;
+}
+static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
+
+static int x1205_attach(struct i2c_adapter *adapter)
+{
+ dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
+ return i2c_probe(adapter, &addr_data, x1205_probe);
+}
+
+static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)
+{
+ int err = 0;
+ unsigned char sr;
+ struct i2c_client *client;
+ struct rtc_device *rtc;
+
+ dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
+ err = -ENODEV;
+ goto exit;
+ }
+
+ if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ /* I2C client */
+ client->addr = address;
+ client->driver = &x1205_driver;
+ client->adapter = adapter;
+
+ strlcpy(client->name, x1205_driver.driver.name, I2C_NAME_SIZE);
+
+ /* Verify the chip is really an X1205 */
+ if (kind < 0) {
+ if (x1205_validate_client(client) < 0) {
+ err = -ENODEV;
+ goto exit_kfree;
+ }
+ }
+
+ /* Inform the i2c layer */
+ if ((err = i2c_attach_client(client)))
+ goto exit_kfree;
+
+ dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+ rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
+ &x1205_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rtc)) {
+ err = PTR_ERR(rtc);
+ dev_err(&client->dev,
+ "unable to register the class device\n");
+ goto exit_detach;
+ }
+
+ i2c_set_clientdata(client, rtc);
+
+ /* Check for power failures and eventualy enable the osc */
+ if ((err = x1205_get_status(client, &sr)) == 0) {
+ if (sr & X1205_SR_RTCF) {
+ dev_err(&client->dev,
+ "power failure detected, "
+ "please set the clock\n");
+ udelay(50);
+ x1205_fix_osc(client);
+ }
+ }
+ else
+ dev_err(&client->dev, "couldn't read status\n");
+
+ device_create_file(&client->dev, &dev_attr_atrim);
+ device_create_file(&client->dev, &dev_attr_dtrim);
+
+ return 0;
+
+exit_detach:
+ i2c_detach_client(client);
+
+exit_kfree:
+ kfree(client);
+
+exit:
+ return err;
+}
+
+static int x1205_detach(struct i2c_client *client)
+{
+ int err;
+ struct rtc_device *rtc = i2c_get_clientdata(client);
+
+ dev_dbg(&client->dev, "%s\n", __FUNCTION__);
+
+ if (rtc)
+ rtc_device_unregister(rtc);
+
+ if ((err = i2c_detach_client(client)))
+ return err;
+
+ kfree(client);
+
+ return 0;
+}
+
+static int __init x1205_init(void)
+{
+ return i2c_add_driver(&x1205_driver);
+}
+
+static void __exit x1205_exit(void)
+{
+ i2c_del_driver(&x1205_driver);
+}
+
+MODULE_AUTHOR(
+ "Karen Spearel <kas111 at gmail dot com>, "
+ "Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(x1205_init);
+module_exit(x1205_exit);