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path: root/drivers/rtc/rtc-x1205.c
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-rw-r--r--drivers/rtc/rtc-x1205.c693
1 files changed, 693 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-x1205.c b/drivers/rtc/rtc-x1205.c
new file mode 100644
index 000000000..f587afa84
--- /dev/null
+++ b/drivers/rtc/rtc-x1205.c
@@ -0,0 +1,693 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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.
+ *
+ * Information and datasheet:
+ * http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
+ */
+
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+
+/* 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_SR_AL0 0x20 /* Alarm 0 match */
+
+#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 */
+
+#define X1205_INT_AL0E 0x20 /* Alarm 0 enable */
+
+static struct i2c_driver x1205_driver;
+
+/*
+ * 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];
+ int i;
+
+ struct i2c_msg msgs[] = {
+ {/* setup read ptr */
+ .addr = client->addr,
+ .len = 2,
+ .buf = dt_addr
+ },
+ {/* read date */
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 8,
+ .buf = buf
+ },
+ };
+
+ /* read date registers */
+ if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ 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",
+ __func__,
+ buf[0], buf[1], buf[2], buf[3],
+ buf[4], buf[5], buf[6], buf[7]);
+
+ /* Mask out the enable bits if these are alarm registers */
+ if (reg_base < X1205_CCR_BASE)
+ for (i = 0; i <= 4; i++)
+ buf[i] &= 0x7F;
+
+ 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",
+ __func__,
+ 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[] = {
+ { /* setup read ptr */
+ .addr = client->addr,
+ .len = 2,
+ .buf = sr_addr
+ },
+ { /* read status */
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 1,
+ .buf = sr
+ },
+ };
+
+ /* read status register */
+ if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
+ u8 reg_base, unsigned char alm_enable)
+{
+ int i, xfer;
+ unsigned char rdata[10] = { 0, reg_base };
+ unsigned char *buf = rdata + 2;
+
+ 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: sec=%d min=%d hour=%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[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;
+
+ 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 + 1900) / 100);
+
+ /* If writing alarm registers, set compare bits on registers 0-4 */
+ if (reg_base < X1205_CCR_BASE)
+ for (i = 0; i <= 4; i++)
+ buf[i] |= 0x80;
+
+ /* this sequence is required to unlock the chip */
+ xfer = i2c_master_send(client, wel, 3);
+ if (xfer != 3) {
+ dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer);
+ return -EIO;
+ }
+
+ xfer = i2c_master_send(client, rwel, 3);
+ if (xfer != 3) {
+ dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer);
+ return -EIO;
+ }
+
+ xfer = i2c_master_send(client, rdata, sizeof(rdata));
+ if (xfer != sizeof(rdata)) {
+ dev_err(&client->dev,
+ "%s: result=%d addr=%02x, data=%02x\n",
+ __func__,
+ xfer, rdata[1], rdata[2]);
+ return -EIO;
+ }
+
+ /* If we wrote to the nonvolatile region, wait 10msec for write cycle*/
+ if (reg_base < X1205_CCR_BASE) {
+ unsigned char al0e[3] = { 0, X1205_REG_INT, 0 };
+
+ msleep(10);
+
+ /* ...and set or clear the AL0E bit in the INT register */
+
+ /* Need to set RWEL again as the write has cleared it */
+ xfer = i2c_master_send(client, rwel, 3);
+ if (xfer != 3) {
+ dev_err(&client->dev,
+ "%s: aloe rwel - %d\n",
+ __func__,
+ xfer);
+ return -EIO;
+ }
+
+ if (alm_enable)
+ al0e[2] = X1205_INT_AL0E;
+
+ xfer = i2c_master_send(client, al0e, 3);
+ if (xfer != 3) {
+ dev_err(&client->dev,
+ "%s: al0e - %d\n",
+ __func__,
+ xfer);
+ return -EIO;
+ }
+
+ /* and wait 10msec again for this write to complete */
+ msleep(10);
+ }
+
+ /* disable further writes */
+ xfer = i2c_master_send(client, diswe, 3);
+ if (xfer != 3) {
+ dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int x1205_fix_osc(struct i2c_client *client)
+{
+ int err;
+ struct rtc_time tm;
+
+ memset(&tm, 0, sizeof(tm));
+
+ err = x1205_set_datetime(client, &tm, X1205_CCR_BASE, 0);
+ if (err < 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[] = {
+ { /* setup read ptr */
+ .addr = client->addr,
+ .len = 2,
+ .buf = dtr_addr
+ },
+ { /* read dtr */
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 1,
+ .buf = &dtr
+ },
+ };
+
+ /* read dtr register */
+ if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, 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[] = {
+ {/* setup read ptr */
+ .addr = client->addr,
+ .len = 2,
+ .buf = atr_addr
+ },
+ {/* read atr */
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 1,
+ .buf = &atr
+ },
+ };
+
+ /* read atr register */
+ if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ dev_dbg(&client->dev, "%s: raw atr=%x\n", __func__, atr);
+
+ /* atr is a two's complement value on 6 bits,
+ * perform sign extension. The formula is
+ * Catr = (atr * 0.25pF) + 11.00pF.
+ */
+ atr = sign_extend32(atr, 5);
+
+ dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr);
+
+ *trim = (atr * 250) + 11000;
+
+ dev_dbg(&client->dev, "%s: real=%d\n", __func__, *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] = {
+ {
+ .addr = client->addr,
+ .len = 2,
+ .buf = addr
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 1,
+ .buf = &buf
+ },
+ };
+
+ xfer = i2c_transfer(client->adapter, msgs, 2);
+ if (xfer != 2) {
+ dev_err(&client->dev,
+ "%s: could not read register %x\n",
+ __func__, probe_zero_pattern[i]);
+
+ return -EIO;
+ }
+
+ if ((buf & probe_zero_pattern[i+1]) != 0) {
+ dev_err(&client->dev,
+ "%s: register=%02x, zero pattern=%d, value=%x\n",
+ __func__, 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] = {
+ {
+ .addr = client->addr,
+ .len = 2,
+ .buf = addr
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 1,
+ .buf = &reg
+ },
+ };
+
+ xfer = i2c_transfer(client->adapter, msgs, 2);
+ if (xfer != 2) {
+ dev_err(&client->dev,
+ "%s: could not read register %x\n",
+ __func__, 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->dev,
+ "%s: register=%x, lim pattern=%d, value=%d\n",
+ __func__, probe_limits_pattern[i].reg,
+ i, value);
+
+ return -ENODEV;
+ }
+ }
+
+ return 0;
+}
+
+static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ int err;
+ unsigned char intreg, status;
+ static unsigned char int_addr[2] = { 0, X1205_REG_INT };
+ struct i2c_client *client = to_i2c_client(dev);
+ struct i2c_msg msgs[] = {
+ { /* setup read ptr */
+ .addr = client->addr,
+ .len = 2,
+ .buf = int_addr
+ },
+ {/* read INT register */
+
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 1,
+ .buf = &intreg
+ },
+ };
+
+ /* read interrupt register and status register */
+ if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+ err = x1205_get_status(client, &status);
+ if (err == 0) {
+ alrm->pending = (status & X1205_SR_AL0) ? 1 : 0;
+ alrm->enabled = (intreg & X1205_INT_AL0E) ? 1 : 0;
+ err = x1205_get_datetime(client, &alrm->time, X1205_ALM0_BASE);
+ }
+ return err;
+}
+
+static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ return x1205_set_datetime(to_i2c_client(dev),
+ &alrm->time, X1205_ALM0_BASE, alrm->enabled);
+}
+
+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, X1205_CCR_BASE, 0);
+}
+
+static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ int err, dtrim, atrim;
+
+ err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
+ if (!err)
+ seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
+
+ err = x1205_get_atrim(to_i2c_client(dev), &atrim);
+ if (!err)
+ seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
+ atrim / 1000, atrim % 1000);
+ return 0;
+}
+
+static const 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 err, atrim;
+
+ err = x1205_get_atrim(to_i2c_client(dev), &atrim);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
+}
+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 err, dtrim;
+
+ err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%d ppm\n", dtrim);
+}
+static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
+
+static int x1205_sysfs_register(struct device *dev)
+{
+ int err;
+
+ err = device_create_file(dev, &dev_attr_atrim);
+ if (err)
+ return err;
+
+ err = device_create_file(dev, &dev_attr_dtrim);
+ if (err)
+ device_remove_file(dev, &dev_attr_atrim);
+
+ return err;
+}
+
+static void x1205_sysfs_unregister(struct device *dev)
+{
+ device_remove_file(dev, &dev_attr_atrim);
+ device_remove_file(dev, &dev_attr_dtrim);
+}
+
+
+static int x1205_probe(struct i2c_client *client)
+{
+ int err = 0;
+ unsigned char sr;
+ struct rtc_device *rtc;
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ if (x1205_validate_client(client) < 0)
+ return -ENODEV;
+
+ rtc = devm_rtc_device_register(&client->dev, x1205_driver.driver.name,
+ &x1205_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ i2c_set_clientdata(client, rtc);
+
+ /* Check for power failures and eventually enable the osc */
+ err = x1205_get_status(client, &sr);
+ if (!err) {
+ 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");
+ }
+
+ err = x1205_sysfs_register(&client->dev);
+ if (err)
+ dev_err(&client->dev, "Unable to create sysfs entries\n");
+
+ return 0;
+}
+
+static void x1205_remove(struct i2c_client *client)
+{
+ x1205_sysfs_unregister(&client->dev);
+}
+
+static const struct i2c_device_id x1205_id[] = {
+ { "x1205", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, x1205_id);
+
+static const struct of_device_id x1205_dt_ids[] = {
+ { .compatible = "xircom,x1205", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, x1205_dt_ids);
+
+static struct i2c_driver x1205_driver = {
+ .driver = {
+ .name = "rtc-x1205",
+ .of_match_table = x1205_dt_ids,
+ },
+ .probe_new = x1205_probe,
+ .remove = x1205_remove,
+ .id_table = x1205_id,
+};
+
+module_i2c_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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 07:06:08 +0000