[PATCH] RTC subsystem, Add ISL1208 support

Add support for the I2C-attached Intersil ISL1208 RTC chip.

[akpm@osdl.org: cleanups, fixlets]
Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 591 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
new file mode 100644
index 0000000..f324d0a
--- /dev/null
+++ b/drivers/rtc/rtc-isl1208.c
@@ -0,0 +1,591 @@
+/*
+ * Intersil ISL1208 rtc class driver
+ *
+ * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
+ *
+ *  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/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+
+#define DRV_NAME "isl1208"
+#define DRV_VERSION "0.2"
+
+/* Register map */
+/* rtc section */
+#define ISL1208_REG_SC  0x00
+#define ISL1208_REG_MN  0x01
+#define ISL1208_REG_HR  0x02
+#define ISL1208_REG_HR_MIL     (1<<7) /* 24h/12h mode */
+#define ISL1208_REG_HR_PM      (1<<5) /* PM/AM bit in 12h mode */
+#define ISL1208_REG_DT  0x03
+#define ISL1208_REG_MO  0x04
+#define ISL1208_REG_YR  0x05
+#define ISL1208_REG_DW  0x06
+#define ISL1208_RTC_SECTION_LEN 7
+
+/* control/status section */
+#define ISL1208_REG_SR  0x07
+#define ISL1208_REG_SR_ARST    (1<<7) /* auto reset */
+#define ISL1208_REG_SR_XTOSCB  (1<<6) /* crystal oscillator */
+#define ISL1208_REG_SR_WRTC    (1<<4) /* write rtc */
+#define ISL1208_REG_SR_ALM     (1<<2) /* alarm */
+#define ISL1208_REG_SR_BAT     (1<<1) /* battery */
+#define ISL1208_REG_SR_RTCF    (1<<0) /* rtc fail */
+#define ISL1208_REG_INT 0x08
+#define ISL1208_REG_09  0x09 /* reserved */
+#define ISL1208_REG_ATR 0x0a
+#define ISL1208_REG_DTR 0x0b
+
+/* alarm section */
+#define ISL1208_REG_SCA 0x0c
+#define ISL1208_REG_MNA 0x0d
+#define ISL1208_REG_HRA 0x0e
+#define ISL1208_REG_DTA 0x0f
+#define ISL1208_REG_MOA 0x10
+#define ISL1208_REG_DWA 0x11
+#define ISL1208_ALARM_SECTION_LEN 6
+
+/* user section */
+#define ISL1208_REG_USR1 0x12
+#define ISL1208_REG_USR2 0x13
+#define ISL1208_USR_SECTION_LEN 2
+
+/* i2c configuration */
+#define ISL1208_I2C_ADDR 0xde
+
+static unsigned short normal_i2c[] = {
+	ISL1208_I2C_ADDR>>1, I2C_CLIENT_END
+};
+I2C_CLIENT_INSMOD; /* defines addr_data */
+
+static int isl1208_attach_adapter(struct i2c_adapter *adapter);
+static int isl1208_detach_client(struct i2c_client *client);
+
+static struct i2c_driver isl1208_driver = {
+	.driver		= {
+		.name	= DRV_NAME,
+	},
+	.id		= I2C_DRIVERID_ISL1208,
+	.attach_adapter = &isl1208_attach_adapter,
+	.detach_client	= &isl1208_detach_client,
+};
+
+/* block read */
+static int
+isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
+		       unsigned len)
+{
+	u8 reg_addr[1] = { reg };
+	struct i2c_msg msgs[2] = {
+		{ client->addr, client->flags, sizeof(reg_addr), reg_addr },
+		{ client->addr, client->flags | I2C_M_RD, len, buf }
+	};
+	int ret;
+
+	BUG_ON(len == 0);
+	BUG_ON(reg > ISL1208_REG_USR2);
+	BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
+
+	ret = i2c_transfer(client->adapter, msgs, 2);
+	if (ret > 0)
+		ret = 0;
+	return ret;
+}
+
+/* block write */
+static int
+isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
+		       unsigned len)
+{
+	u8 i2c_buf[ISL1208_REG_USR2 + 2];
+	struct i2c_msg msgs[1] = {
+		{ client->addr, client->flags, len + 1, i2c_buf }
+	};
+	int ret;
+
+	BUG_ON(len == 0);
+	BUG_ON(reg > ISL1208_REG_USR2);
+	BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
+
+	i2c_buf[0] = reg;
+	memcpy(&i2c_buf[1], &buf[0], len);
+
+	ret = i2c_transfer(client->adapter, msgs, 1);
+	if (ret > 0)
+		ret = 0;
+	return ret;
+}
+
+/* simple check to see wether we have a isl1208 */
+static int isl1208_i2c_validate_client(struct i2c_client *client)
+{
+	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
+	u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
+		0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
+	};
+	int i;
+	int ret;
+
+	ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
+		if (regs[i] & zero_mask[i]) /* check if bits are cleared */
+			return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int isl1208_i2c_get_sr(struct i2c_client *client)
+{
+	return i2c_smbus_read_byte_data(client, ISL1208_REG_SR) == -1 ? -EIO:0;
+}
+
+static int isl1208_i2c_get_atr(struct i2c_client *client)
+{
+	int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
+
+	if (atr < 0)
+		return -EIO;
+
+	/* The 6bit value in the ATR register controls the load
+	 * capacitance C_load * in steps of 0.25pF
+	 *
+	 * bit (1<<5) of the ATR register is inverted
+	 *
+	 * C_load(ATR=0x20) =  4.50pF
+	 * C_load(ATR=0x00) = 12.50pF
+	 * C_load(ATR=0x1f) = 20.25pF
+	 *
+	 */
+
+	atr &= 0x3f; /* mask out lsb */
+	atr ^= 1<<5; /* invert 6th bit */
+	atr += 2*9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
+
+	return atr;
+}
+
+static int isl1208_i2c_get_dtr(struct i2c_client *client)
+{
+	int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
+
+	if (dtr < 0)
+		return -EIO;
+
+	/* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
+	dtr = ((dtr & 0x3) * 20) * (dtr & (1<<2) ? -1 : 1);
+
+	return dtr;
+}
+
+static int isl1208_i2c_get_usr(struct i2c_client *client)
+{
+	u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
+	int ret;
+
+	ret = isl1208_i2c_read_regs (client, ISL1208_REG_USR1, buf,
+				   ISL1208_USR_SECTION_LEN);
+	if (ret < 0)
+		return ret;
+
+	return (buf[1] << 8) | buf[0];
+}
+
+static int isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
+{
+	u8 buf[ISL1208_USR_SECTION_LEN];
+
+	buf[0] = usr & 0xff;
+	buf[1] = (usr >> 8) & 0xff;
+
+	return isl1208_i2c_set_regs (client, ISL1208_REG_USR1, buf,
+				     ISL1208_USR_SECTION_LEN);
+}
+
+static int isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	struct i2c_client *const client = to_i2c_client(dev);
+	int sr, dtr, atr, usr;
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+
+	seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
+		   (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
+		   (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
+		   (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
+		   (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
+		   (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
+		   (sr & ISL1208_REG_SR_ARST) ? " ARST" : "",
+		   sr);
+
+	seq_printf(seq, "batt_status\t: %s\n",
+		   (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
+
+	dtr = isl1208_i2c_get_dtr(client);
+	if (dtr >= 0 -1)
+		seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
+
+	atr = isl1208_i2c_get_atr(client);
+	if (atr >= 0)
+		seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
+			   atr>>2, (atr&0x3)*25);
+
+	usr = isl1208_i2c_get_usr(client);
+	if (usr >= 0)
+		seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
+
+	return 0;
+}
+
+
+static int isl1208_i2c_read_time(struct i2c_client *client,
+				 struct rtc_time *tm)
+{
+	int sr;
+	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return -EIO;
+	}
+
+	sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading RTC section failed\n",
+			__func__);
+		return sr;
+	}
+
+	tm->tm_sec = BCD2BIN(regs[ISL1208_REG_SC]);
+	tm->tm_min = BCD2BIN(regs[ISL1208_REG_MN]);
+	{ /* HR field has a more complex interpretation */
+		const u8 _hr = regs[ISL1208_REG_HR];
+		if (_hr & ISL1208_REG_HR_MIL) /* 24h format */
+			tm->tm_hour = BCD2BIN(_hr & 0x3f);
+		else { // 12h format
+			tm->tm_hour = BCD2BIN(_hr & 0x1f);
+			if (_hr & ISL1208_REG_HR_PM) /* PM flag set */
+				tm->tm_hour += 12;
+		}
+	}
+
+	tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DT]);
+	tm->tm_mon = BCD2BIN(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
+	tm->tm_year = BCD2BIN(regs[ISL1208_REG_YR]) + 100;
+	tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DW]);
+
+	return 0;
+}
+
+static int isl1208_i2c_read_alarm(struct i2c_client *client,
+				  struct rtc_wkalrm *alarm)
+{
+	struct rtc_time *const tm = &alarm->time;
+	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
+	int sr;
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+
+	sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
+				  ISL1208_ALARM_SECTION_LEN);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading alarm section failed\n",
+			__func__);
+		return sr;
+	}
+
+	/* MSB of each alarm register is an enable bit */
+	tm->tm_sec  = BCD2BIN(regs[ISL1208_REG_SCA-ISL1208_REG_SCA] & 0x7f);
+	tm->tm_min  = BCD2BIN(regs[ISL1208_REG_MNA-ISL1208_REG_SCA] & 0x7f);
+	tm->tm_hour = BCD2BIN(regs[ISL1208_REG_HRA-ISL1208_REG_SCA] & 0x3f);
+	tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DTA-ISL1208_REG_SCA] & 0x3f);
+	tm->tm_mon  = BCD2BIN(regs[ISL1208_REG_MOA-ISL1208_REG_SCA] & 0x1f)-1;
+	tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DWA-ISL1208_REG_SCA] & 0x03);
+
+	return 0;
+}
+
+static int isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	return isl1208_i2c_read_time(to_i2c_client(dev), tm);
+}
+
+static int isl1208_i2c_set_time(struct i2c_client *client,
+				struct rtc_time const *tm)
+{
+	int sr;
+	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
+
+	regs[ISL1208_REG_SC] = BIN2BCD(tm->tm_sec);
+	regs[ISL1208_REG_MN] = BIN2BCD(tm->tm_min);
+	regs[ISL1208_REG_HR] = BIN2BCD(tm->tm_hour) | ISL1208_REG_HR_MIL;
+
+	regs[ISL1208_REG_DT] = BIN2BCD(tm->tm_mday);
+	regs[ISL1208_REG_MO] = BIN2BCD(tm->tm_mon + 1);
+	regs[ISL1208_REG_YR] = BIN2BCD(tm->tm_year - 100);
+
+	regs[ISL1208_REG_DW] = BIN2BCD(tm->tm_wday & 7);
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+
+	/* set WRTC */
+	sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
+				       sr | ISL1208_REG_SR_WRTC);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
+		return sr;
+	}
+
+	/* write RTC registers */
+	sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: writing RTC section failed\n",
+			__func__);
+		return sr;
+	}
+
+	/* clear WRTC again */
+	sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
+				       sr & ~ISL1208_REG_SR_WRTC);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
+		return sr;
+	}
+
+	return 0;
+}
+
+
+static int isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	return isl1208_i2c_set_time(to_i2c_client(dev), tm);
+}
+
+static int isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
+}
+
+static struct rtc_class_ops isl1208_rtc_ops = {
+	.proc		= isl1208_rtc_proc,
+	.read_time	= isl1208_rtc_read_time,
+	.set_time	= isl1208_rtc_set_time,
+	.read_alarm	= isl1208_rtc_read_alarm,
+	//.set_alarm	= isl1208_rtc_set_alarm,
+};
+
+/* sysfs interface */
+
+static ssize_t isl1208_sysfs_show_atrim(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	int atr;
+
+	atr = isl1208_i2c_get_atr(to_i2c_client(dev));
+	if (atr < 0)
+		return atr;
+
+	return sprintf(buf, "%d.%.2d pF\n", atr>>2, (atr&0x3)*25);
+}
+static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
+
+static ssize_t isl1208_sysfs_show_dtrim(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	int dtr;
+
+	dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
+	if (dtr < 0)
+		return dtr;
+
+	return sprintf(buf, "%d ppm\n", dtr);
+}
+static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
+
+static ssize_t isl1208_sysfs_show_usr(struct device *dev,
+				       struct device_attribute *attr,
+				       char *buf)
+{
+	int usr;
+
+	usr = isl1208_i2c_get_usr(to_i2c_client(dev));
+	if (usr < 0)
+		return usr;
+
+	return sprintf(buf, "0x%.4x\n", usr);
+}
+
+static ssize_t isl1208_sysfs_store_usr(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t count)
+{
+	int usr = -1;
+
+	if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
+		if (sscanf(buf, "%x", &usr) != 1)
+			return -EINVAL;
+	} else {
+		if (sscanf(buf, "%d", &usr) != 1)
+			return -EINVAL;
+	}
+
+	if (usr < 0 || usr > 0xffff)
+		return -EINVAL;
+
+	return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
+}
+static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
+		   isl1208_sysfs_store_usr);
+
+static int
+isl1208_probe(struct i2c_adapter *adapter, int addr, int kind)
+{
+	int rc = 0;
+	struct i2c_client *new_client = NULL;
+	struct rtc_device *rtc = NULL;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
+		rc = -ENODEV;
+		goto failout;
+	}
+
+	new_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
+	if (new_client == NULL) {
+		rc = -ENOMEM;
+		goto failout;
+	}
+
+	new_client->addr = addr;
+	new_client->adapter = adapter;
+	new_client->driver = &isl1208_driver;
+	new_client->flags = 0;
+	strcpy(new_client->name, DRV_NAME);
+
+	if (kind < 0) {
+		rc = isl1208_i2c_validate_client(new_client);
+		if (rc < 0)
+			goto failout;
+	}
+
+	rc = i2c_attach_client(new_client);
+	if (rc < 0)
+		goto failout;
+
+	dev_info(&new_client->dev,
+		 "chip found, driver version " DRV_VERSION "\n");
+
+	rtc = rtc_device_register(isl1208_driver.driver.name,
+				  &new_client->dev,
+				  &isl1208_rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(rtc)) {
+		rc = PTR_ERR(rtc);
+		goto failout_detach;
+	}
+
+	i2c_set_clientdata(new_client, rtc);
+
+	rc = isl1208_i2c_get_sr(new_client);
+	if (rc < 0) {
+		dev_err(&new_client->dev, "reading status failed\n");
+		goto failout_unregister;
+	}
+
+	if (rc & ISL1208_REG_SR_RTCF)
+		dev_warn(&new_client->dev, "rtc power failure detected, "
+			 "please set clock.\n");
+
+	rc = device_create_file(&new_client->dev, &dev_attr_atrim);
+	if (rc < 0)
+		goto failout_unregister;
+	rc = device_create_file(&new_client->dev, &dev_attr_dtrim);
+	if (rc < 0)
+		goto failout_atrim;
+	rc = device_create_file(&new_client->dev, &dev_attr_usr);
+	if (rc < 0)
+		goto failout_dtrim;
+
+	return 0;
+
+ failout_dtrim:
+	device_remove_file(&new_client->dev, &dev_attr_dtrim);
+ failout_atrim:
+	device_remove_file(&new_client->dev, &dev_attr_atrim);
+ failout_unregister:
+	rtc_device_unregister(rtc);
+ failout_detach:
+	i2c_detach_client(new_client);
+ failout:
+	kfree(new_client);
+	return rc;
+}
+
+static int
+isl1208_attach_adapter (struct i2c_adapter *adapter)
+{
+	return i2c_probe(adapter, &addr_data, isl1208_probe);
+}
+
+static int
+isl1208_detach_client(struct i2c_client *client)
+{
+	int rc;
+	struct rtc_device *const rtc = i2c_get_clientdata(client);
+
+	if (rtc)
+		rtc_device_unregister(rtc); /* do we need to kfree? */
+
+	rc = i2c_detach_client(client);
+	if (rc)
+		return rc;
+
+	kfree(client);
+
+	return 0;
+}
+
+/* module management */
+
+static int __init isl1208_init(void)
+{
+	return i2c_add_driver(&isl1208_driver);
+}
+
+static void __exit isl1208_exit(void)
+{
+	i2c_del_driver(&isl1208_driver);
+}
+
+MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
+MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(isl1208_init);
+module_exit(isl1208_exit);