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Date:	Tue, 14 Jun 2011 16:14:57 +1200
From:	Austin Boyle <Austin.Boyle@...atnet.com>
To:	Alessandro Zummo <a.zummo@...ertech.it>
CC:	<rtc-linux@...glegroups.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2.6.39-rc7] RTC: rtc-ds1307 EEPROM support for ds1388
 chip

On Mon, 2011-05-23 at 17:18 +1200, Austin Boyle wrote:
> This is my patch which extends the NVRAM access functions in the DS1307
> driver to support the 512 bytes of EEPROM on the DS1388 chip. Could you
> please review the patch? If there are any problems with the way I have
> implemented this or suggested improvements I will gladly modify. Thanks!

This is an updated version of the patch which prints the correct NVRAM
size at init. Could someone please give me some feedback?

[PATCH 3.0-rc3] RTC: rtc-ds1307: EEPROM support for ds1388 chip

This patch adds support for different sized NVRAM, such as
the 512 bytes of EEPROM on the DS1388 chip.

Cc: Alessandro Zummo <a.zummo@...ertech.it>
Signed-off-by: Austin Boyle <austin.boyle@...atnet.com>
---
diff -upNr a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
--- a/drivers/rtc/rtc-ds1307.c	2011-06-14 15:56:45.221497487 +1200
+++ b/drivers/rtc/rtc-ds1307.c	2011-06-14 15:57:28.803510835 +1200
@@ -95,15 +95,19 @@ enum ds_type {
 #	define RX8025_BIT_VDET		0x40
 #	define RX8025_BIT_XST		0x20
 
+#define DS1307_MAX_NUM_ADDRS	3
 
 struct ds1307 {
 	u8			offset; /* register's offset */
+	u16			nvram_size;
+	u16			nvram_offset;
+	u8			num_addrs;
 	u8			regs[11];
 	enum ds_type		type;
 	unsigned long		flags;
 #define HAS_NVRAM	0		/* bit 0 == sysfs file active */
 #define HAS_ALARM	1		/* bit 1 == irq claimed */
-	struct i2c_client	*client;
+	struct i2c_client	*client[DS1307_MAX_NUM_ADDRS];
 	struct rtc_device	*rtc;
 	struct work_struct	work;
 	s32 (*read_block_data)(const struct i2c_client *client, u8 command,
@@ -113,23 +117,26 @@ struct ds1307 {
 };
 
 struct chip_desc {
-	unsigned		nvram56:1;
+	unsigned		nvram:1;
 	unsigned		alarm:1;
 };
 
 static const struct chip_desc chips[] = {
 [ds_1307] = {
-	.nvram56	= 1,
+	.nvram		= 1,
 },
 [ds_1337] = {
 	.alarm		= 1,
 },
 [ds_1338] = {
-	.nvram56	= 1,
+	.nvram		= 1,
 },
 [ds_1339] = {
 	.alarm		= 1,
 },
+[ds_1388] = {
+	.nvram		= 1,
+},
 [ds_1340] = {
 },
 [ds_3231] = {
@@ -248,7 +255,7 @@ static void ds1307_work(struct work_stru
 	int			stat, control;
 
 	ds1307 = container_of(work, struct ds1307, work);
-	client = ds1307->client;
+	client = ds1307->client[0];
 	lock = &ds1307->rtc->ops_lock;
 
 	mutex_lock(lock);
@@ -294,7 +301,7 @@ static int ds1307_get_time(struct device
 	int		tmp;
 
 	/* read the RTC date and time registers all at once */
-	tmp = ds1307->read_block_data(ds1307->client,
+	tmp = ds1307->read_block_data(ds1307->client[0],
 		ds1307->offset, 7, ds1307->regs);
 	if (tmp != 7) {
 		dev_err(dev, "%s error %d\n", "read", tmp);
@@ -372,7 +379,7 @@ static int ds1307_set_time(struct device
 		"write", buf[0], buf[1], buf[2], buf[3],
 		buf[4], buf[5], buf[6]);
 
-	result = ds1307->write_block_data(ds1307->client,
+	result = ds1307->write_block_data(ds1307->client[0],
 		ds1307->offset, 7, buf);
 	if (result < 0) {
 		dev_err(dev, "%s error %d\n", "write", result);
@@ -530,8 +537,6 @@ static const struct rtc_class_ops ds13xx
 
 /*----------------------------------------------------------------------*/
 
-#define NVRAM_SIZE	56
-
 static ssize_t
 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 		struct bin_attribute *attr,
@@ -540,18 +545,39 @@ ds1307_nvram_read(struct file *filp, str
 	struct i2c_client	*client;
 	struct ds1307		*ds1307;
 	int			result;
+	unsigned int		addr = 0;
 
 	client = kobj_to_i2c_client(kobj);
 	ds1307 = i2c_get_clientdata(client);
 
-	if (unlikely(off >= NVRAM_SIZE))
+	if (unlikely(off >= ds1307->nvram_size))
 		return 0;
-	if ((off + count) > NVRAM_SIZE)
-		count = NVRAM_SIZE - off;
+	if ((off + count) > ds1307->nvram_size)
+		count = ds1307->nvram_size - off;
 	if (unlikely(!count))
 		return count;
 
-	result = ds1307->read_block_data(client, 8 + off, count, buf);
+	if (ds1307->nvram_offset < 0xff) {	/* ds1307, ds1338 */
+		result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
count, buf);
+	} else	{	/* ds1388 */
+		if ((off <= 0x00ff) && (off + count > 0x00ff))	{	/* read spans two
blocks */
+			client = ds1307->client[1];		/* first block */
+			addr = (unsigned int)off;
+			result = ds1307->read_block_data(client, addr, (0x100-addr), buf);
+			client = ds1307->client[2];		/* second block */
+			result += ds1307->read_block_data(client, 0x00, (count+addr-0x100),
(buf+0x100-addr));
+
+		} else { 	/* read spans one blocks */
+			if (off <= 0x00ff)	{
+				client = ds1307->client[1];
+				addr = (unsigned int)off;
+			} else if (off <= 0x0200)	{
+				client = ds1307->client[2];
+				addr = (unsigned int)off - 0x100;
+			}
+			result = ds1307->read_block_data(client, addr, count, buf);
+		}
+	}
 	if (result < 0)
 		dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 	return result;
@@ -565,18 +591,40 @@ ds1307_nvram_write(struct file *filp, st
 	struct i2c_client	*client;
 	struct ds1307		*ds1307;
 	int			result;
+	unsigned int		addr = 0;
 
 	client = kobj_to_i2c_client(kobj);
 	ds1307 = i2c_get_clientdata(client);
 
-	if (unlikely(off >= NVRAM_SIZE))
+	if (unlikely(off >= ds1307->nvram_size))
 		return -EFBIG;
-	if ((off + count) > NVRAM_SIZE)
-		count = NVRAM_SIZE - off;
+	if ((off + count) > ds1307->nvram_size)
+		count = ds1307->nvram_size - off;
 	if (unlikely(!count))
 		return count;
 
-	result = ds1307->write_block_data(client, 8 + off, count, buf);
+	if (ds1307->nvram_offset < 0xff) {	/* ds1307, ds1338 */
+		result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
count, buf);
+	} else	{	/* ds1388 */
+		if ((off <= 0x00ff) && ((off + count) > 0x00ff))	{  /* read spans two
blocks */
+			client = ds1307->client[1];		/* first block */
+			addr = (unsigned int)off;
+			result = ds1307->write_block_data(client, addr, (0x100-addr), buf);
+			client = ds1307->client[2];		/* second block */
+			result = ds1307->write_block_data(client, 0x00, (addr+count-0x100),
(buf+0x100-addr));
+
+		} else { /* Device address/offset translation */
+			dev_dbg(&client->dev, "Write spans one block\n");
+			if (off <= 0x00ff)	{
+				client = ds1307->client[1];
+				addr = (unsigned int)off;
+			} else if (off <= 0x0200)	{
+				client = ds1307->client[2];
+				addr = (unsigned int)off - 0x100;
+			}
+			result = ds1307->write_block_data(client, addr, count, buf);
+		}
+	}
 	if (result < 0) {
 		dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 		return result;
@@ -592,7 +640,6 @@ static struct bin_attribute nvram = {
 
 	.read	= ds1307_nvram_read,
 	.write	= ds1307_nvram_write,
-	.size	= NVRAM_SIZE,
 };
 
 /*----------------------------------------------------------------------*/
@@ -605,6 +652,7 @@ static int __devinit ds1307_probe(struct
 	struct ds1307		*ds1307;
 	int			err = -ENODEV;
 	int			tmp;
+	int			i;
 	const struct chip_desc	*chip = &chips[id->driver_data];
 	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);
 	int			want_irq = false;
@@ -624,9 +672,10 @@ static int __devinit ds1307_probe(struct
 
 	i2c_set_clientdata(client, ds1307);
 
-	ds1307->client	= client;
+	ds1307->client[0] = client;
 	ds1307->type	= id->driver_data;
 	ds1307->offset	= 0;
+	ds1307->num_addrs = 1;
 
 	buf = ds1307->regs;
 	if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
@@ -642,12 +691,12 @@ static int __devinit ds1307_probe(struct
 	case ds_1339:
 	case ds_3231:
 		/* has IRQ? */
-		if (ds1307->client->irq > 0 && chip->alarm) {
+		if (client->irq > 0 && chip->alarm) {
 			INIT_WORK(&ds1307->work, ds1307_work);
 			want_irq = true;
 		}
 		/* get registers that the "rtc" read below won't read... */
-		tmp = ds1307->read_block_data(ds1307->client,
+		tmp = ds1307->read_block_data(client,
 				DS1337_REG_CONTROL, 2, buf);
 		if (tmp != 2) {
 			pr_debug("read error %d\n", tmp);
@@ -681,7 +730,7 @@ static int __devinit ds1307_probe(struct
 		break;
 
 	case rx_8025:
-		tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
+		tmp = i2c_smbus_read_i2c_block_data(client,
 				RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 		if (tmp != 2) {
 			pr_debug("read error %d\n", tmp);
@@ -747,6 +796,14 @@ static int __devinit ds1307_probe(struct
 		break;
 	case ds_1388:
 		ds1307->offset = 1; /* Seconds starts at 1 */
+		ds1307->num_addrs = 3;	/* uses 3 I2C addrs */
+		ds1307->nvram_size = 512; /* 512 bytes EEPROM */
+		ds1307->nvram_offset = 0xff;
+		break;
+	case ds_1307:
+	case ds_1338:
+		ds1307->nvram_size = 56; /* 56 bytes NVRAM */
+		ds1307->nvram_offset = 8;
 		break;
 	default:
 		break;
@@ -754,7 +811,7 @@ static int __devinit ds1307_probe(struct
 
 read_rtc:
 	/* read RTC registers */
-	tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
+	tmp = ds1307->read_block_data(client, ds1307->offset, 8, buf);
 	if (tmp != 8) {
 		pr_debug("read error %d\n", tmp);
 		err = -EIO;
@@ -866,16 +923,35 @@ read_rtc:
 		dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 	}
 
-	if (chip->nvram56) {
+	if (chip->nvram) {
+		nvram.size = ds1307->nvram_size;
 		err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
 		if (err == 0) {
 			set_bit(HAS_NVRAM, &ds1307->flags);
-			dev_info(&client->dev, "56 bytes nvram\n");
+			dev_info(&client->dev, "%d bytes nvram\n", nvram.size);
+		}
+	}
+
+	/* use dummy devices for multiple address chips */
+	for (i = 1; i < ds1307->num_addrs; i++) {
+		ds1307->client[i] = i2c_new_dummy(client->adapter, client->addr + i);
+		if (!ds1307->client[i]) {
+			dev_err(&client->dev, "address 0x%02x unavailable\n",
+					client->addr + i);
+			err = -EADDRINUSE;
+			goto err_clients;
 		}
+		i2c_set_clientdata(ds1307->client[i], ds1307);
 	}
 
 	return 0;
 
+err_clients:
+	for (i = 1; i < ds1307->num_addrs; i++)	{
+		if (ds1307->client[i])	{
+			i2c_unregister_device(ds1307->client[i]);
+		}
+	}
 exit_irq:
 	rtc_device_unregister(ds1307->rtc);
 exit_free:

--
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