1 files changed, 203 insertions, 89 deletions

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index d4775528abc..d87f77f790d 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -20,8 +20,9 @@
 #include <linux/log2.h>
 #include <linux/bitops.h>
 #include <linux/jiffies.h>
+#include <linux/of.h>
 #include <linux/i2c.h>
-#include <linux/i2c/at24.h>
+#include <linux/platform_data/at24.h>
 
 /*
  * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable.
@@ -53,7 +54,8 @@
 
 struct at24_data {
 	struct at24_platform_data chip;
-	bool use_smbus;
+	struct memory_accessor macc;
+	int use_smbus;
 
 	/*
 	 * Lock protects against activities from other Linux tasks,
@@ -157,6 +159,7 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
 	struct i2c_msg msg[2];
 	u8 msgbuf[2];
 	struct i2c_client *client;
+	unsigned long timeout, read_time;
 	int status, i;
 
 	memset(msg, 0, sizeof(msg));
@@ -182,57 +185,92 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
 	if (count > io_limit)
 		count = io_limit;
 
-	/* Smaller eeproms can work given some SMBus extension calls */
-	if (at24->use_smbus) {
+	switch (at24->use_smbus) {
+	case I2C_SMBUS_I2C_BLOCK_DATA:
+		/* Smaller eeproms can work given some SMBus extension calls */
 		if (count > I2C_SMBUS_BLOCK_MAX)
 			count = I2C_SMBUS_BLOCK_MAX;
-		status = i2c_smbus_read_i2c_block_data(client, offset,
-				count, buf);
-		dev_dbg(&client->dev, "smbus read %zu@%d --> %d\n",
-				count, offset, status);
-		return (status < 0) ? -EIO : status;
+		break;
+	case I2C_SMBUS_WORD_DATA:
+		count = 2;
+		break;
+	case I2C_SMBUS_BYTE_DATA:
+		count = 1;
+		break;
+	default:
+		/*
+		 * When we have a better choice than SMBus calls, use a
+		 * combined I2C message. Write address; then read up to
+		 * io_limit data bytes. Note that read page rollover helps us
+		 * here (unlike writes). msgbuf is u8 and will cast to our
+		 * needs.
+		 */
+		i = 0;
+		if (at24->chip.flags & AT24_FLAG_ADDR16)
+			msgbuf[i++] = offset >> 8;
+		msgbuf[i++] = offset;
+
+		msg[0].addr = client->addr;
+		msg[0].buf = msgbuf;
+		msg[0].len = i;
+
+		msg[1].addr = client->addr;
+		msg[1].flags = I2C_M_RD;
+		msg[1].buf = buf;
+		msg[1].len = count;
 	}
 
 	/*
-	 * When we have a better choice than SMBus calls, use a combined
-	 * I2C message. Write address; then read up to io_limit data bytes.
-	 * Note that read page rollover helps us here (unlike writes).
-	 * msgbuf is u8 and will cast to our needs.
+	 * Reads fail if the previous write didn't complete yet. We may
+	 * loop a few times until this one succeeds, waiting at least
+	 * long enough for one entire page write to work.
 	 */
-	i = 0;
-	if (at24->chip.flags & AT24_FLAG_ADDR16)
-		msgbuf[i++] = offset >> 8;
-	msgbuf[i++] = offset;
-
-	msg[0].addr = client->addr;
-	msg[0].buf = msgbuf;
-	msg[0].len = i;
+	timeout = jiffies + msecs_to_jiffies(write_timeout);
+	do {
+		read_time = jiffies;
+		switch (at24->use_smbus) {
+		case I2C_SMBUS_I2C_BLOCK_DATA:
+			status = i2c_smbus_read_i2c_block_data(client, offset,
+					count, buf);
+			break;
+		case I2C_SMBUS_WORD_DATA:
+			status = i2c_smbus_read_word_data(client, offset);
+			if (status >= 0) {
+				buf[0] = status & 0xff;
+				buf[1] = status >> 8;
+				status = count;
+			}
+			break;
+		case I2C_SMBUS_BYTE_DATA:
+			status = i2c_smbus_read_byte_data(client, offset);
+			if (status >= 0) {
+				buf[0] = status;
+				status = count;
+			}
+			break;
+		default:
+			status = i2c_transfer(client->adapter, msg, 2);
+			if (status == 2)
+				status = count;
+		}
+		dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
+				count, offset, status, jiffies);
 
-	msg[1].addr = client->addr;
-	msg[1].flags = I2C_M_RD;
-	msg[1].buf = buf;
-	msg[1].len = count;
+		if (status == count)
+			return count;
 
-	status = i2c_transfer(client->adapter, msg, 2);
-	dev_dbg(&client->dev, "i2c read %zu@%d --> %d\n",
-			count, offset, status);
+		/* REVISIT: at HZ=100, this is sloooow */
+		msleep(1);
+	} while (time_before(read_time, timeout));
 
-	if (status == 2)
-		return count;
-	else if (status >= 0)
-		return -EIO;
-	else
-		return status;
+	return -ETIMEDOUT;
 }
 
-static ssize_t at24_bin_read(struct kobject *kobj, struct bin_attribute *attr,
+static ssize_t at24_read(struct at24_data *at24,
 		char *buf, loff_t off, size_t count)
 {
-	struct at24_data *at24;
 	ssize_t retval = 0;
 
-	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
-
 	if (unlikely(!count))
 		return count;
 
@@ -262,12 +300,15 @@ static ssize_t at24_bin_read(struct kobject *kobj, struct bin_attribute *attr,
 	return retval;
 }
 
+static ssize_t at24_bin_read(struct file *filp, struct kobject *kobj,
+		struct bin_attribute *attr,
+		char *buf, loff_t off, size_t count)
+{
+	struct at24_data *at24;
 
-/*
- * REVISIT: export at24_bin{read,write}() to let other kernel code use
- * eeprom data. For example, it might hold a board's Ethernet address, or
- * board-specific calibration data generated on the manufacturing floor.
- */
+	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
+	return at24_read(at24, buf, off, count);
+}
 
 
 /*
@@ -278,7 +319,7 @@ static ssize_t at24_bin_read(struct kobject *kobj, struct bin_attribute *attr,
  * We only use page mode writes; the alternative is sloooow. This routine
  * writes at most one page.
  */
-static ssize_t at24_eeprom_write(struct at24_data *at24, char *buf,
+static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
 		unsigned offset, size_t count)
 {
 	struct i2c_client *client;
@@ -347,14 +388,11 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, char *buf,
 	return -ETIMEDOUT;
 }
 
-static ssize_t at24_bin_write(struct kobject *kobj, struct bin_attribute *attr,
-		char *buf, loff_t off, size_t count)
+static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off,
+			  size_t count)
 {
-	struct at24_data *at24;
 	ssize_t retval = 0;
 
-	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
-
 	if (unlikely(!count))
 		return count;
 
@@ -384,13 +422,71 @@ static ssize_t at24_bin_write(struct kobject *kobj, struct bin_attribute *attr,
 	return retval;
 }
 
+static ssize_t at24_bin_write(struct file *filp, struct kobject *kobj,
+		struct bin_attribute *attr,
+		char *buf, loff_t off, size_t count)
+{
+	struct at24_data *at24;
+
+	if (unlikely(off >= attr->size))
+		return -EFBIG;
+
+	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
+	return at24_write(at24, buf, off, count);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * This lets other kernel code access the eeprom data. For example, it
+ * might hold a board's Ethernet address, or board-specific calibration
+ * data generated on the manufacturing floor.
+ */
+
+static ssize_t at24_macc_read(struct memory_accessor *macc, char *buf,
+			 off_t offset, size_t count)
+{
+	struct at24_data *at24 = container_of(macc, struct at24_data, macc);
+
+	return at24_read(at24, buf, offset, count);
+}
+
+static ssize_t at24_macc_write(struct memory_accessor *macc, const char *buf,
+			  off_t offset, size_t count)
+{
+	struct at24_data *at24 = container_of(macc, struct at24_data, macc);
+
+	return at24_write(at24, buf, offset, count);
+}
+
 /*-------------------------------------------------------------------------*/
 
+#ifdef CONFIG_OF
+static void at24_get_ofdata(struct i2c_client *client,
+		struct at24_platform_data *chip)
+{
+	const __be32 *val;
+	struct device_node *node = client->dev.of_node;
+
+	if (node) {
+		if (of_get_property(node, "read-only", NULL))
+			chip->flags |= AT24_FLAG_READONLY;
+		val = of_get_property(node, "pagesize", NULL);
+		if (val)
+			chip->page_size = be32_to_cpup(val);
+	}
+}
+#else
+static void at24_get_ofdata(struct i2c_client *client,
+		struct at24_platform_data *chip)
+{ }
+#endif /* CONFIG_OF */
+
 static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct at24_platform_data chip;
 	bool writable;
-	bool use_smbus = false;
+	int use_smbus = 0;
 	struct at24_data *at24;
 	int err;
 	unsigned i, num_addresses;
@@ -399,10 +495,9 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (client->dev.platform_data) {
 		chip = *(struct at24_platform_data *)client->dev.platform_data;
 	} else {
-		if (!id->driver_data) {
-			err = -ENODEV;
-			goto err_out;
-		}
+		if (!id->driver_data)
+			return -ENODEV;
+
 		magic = id->driver_data;
 		chip.byte_len = BIT(magic & AT24_BITMASK(AT24_SIZE_BYTELEN));
 		magic >>= AT24_SIZE_BYTELEN;
@@ -413,27 +508,42 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		 * is recommended anyhow.
 		 */
 		chip.page_size = 1;
+
+		/* update chipdata if OF is present */
+		at24_get_ofdata(client, &chip);
+
+		chip.setup = NULL;
+		chip.context = NULL;
 	}
 
 	if (!is_power_of_2(chip.byte_len))
 		dev_warn(&client->dev,
 			"byte_len looks suspicious (no power of 2)!\n");
+	if (!chip.page_size) {
+		dev_err(&client->dev, "page_size must not be 0!\n");
+		return -EINVAL;
+	}
 	if (!is_power_of_2(chip.page_size))
 		dev_warn(&client->dev,
 			"page_size looks suspicious (no power of 2)!\n");
 
 	/* Use I2C operations unless we're stuck with SMBus extensions. */
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
-		if (chip.flags & AT24_FLAG_ADDR16) {
-			err = -EPFNOSUPPORT;
-			goto err_out;
-		}
-		if (!i2c_check_functionality(client->adapter,
+		if (chip.flags & AT24_FLAG_ADDR16)
+			return -EPFNOSUPPORT;
+
+		if (i2c_check_functionality(client->adapter,
 				I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
-			err = -EPFNOSUPPORT;
-			goto err_out;
+			use_smbus = I2C_SMBUS_I2C_BLOCK_DATA;
+		} else if (i2c_check_functionality(client->adapter,
+				I2C_FUNC_SMBUS_READ_WORD_DATA)) {
+			use_smbus = I2C_SMBUS_WORD_DATA;
+		} else if (i2c_check_functionality(client->adapter,
+				I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+			use_smbus = I2C_SMBUS_BYTE_DATA;
+		} else {
+			return -EPFNOSUPPORT;
 		}
-		use_smbus = true;
 	}
 
 	if (chip.flags & AT24_FLAG_TAKE8ADDR)
@@ -442,12 +552,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		num_addresses =	DIV_ROUND_UP(chip.byte_len,
 			(chip.flags & AT24_FLAG_ADDR16) ? 65536 : 256);
 
-	at24 = kzalloc(sizeof(struct at24_data) +
+	at24 = devm_kzalloc(&client->dev, sizeof(struct at24_data) +
 		num_addresses * sizeof(struct i2c_client *), GFP_KERNEL);
-	if (!at24) {
-		err = -ENOMEM;
-		goto err_out;
-	}
+	if (!at24)
+		return -ENOMEM;
 
 	mutex_init(&at24->lock);
 	at24->use_smbus = use_smbus;
@@ -458,11 +566,14 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	 * Export the EEPROM bytes through sysfs, since that's convenient.
 	 * By default, only root should see the data (maybe passwords etc)
 	 */
+	sysfs_bin_attr_init(&at24->bin);
 	at24->bin.attr.name = "eeprom";
 	at24->bin.attr.mode = chip.flags & AT24_FLAG_IRUGO ? S_IRUGO : S_IRUSR;
 	at24->bin.read = at24_bin_read;
 	at24->bin.size = chip.byte_len;
 
+	at24->macc.read = at24_macc_read;
+
 	writable = !(chip.flags & AT24_FLAG_READONLY);
 	if (writable) {
 		if (!use_smbus || i2c_check_functionality(client->adapter,
@@ -470,6 +581,8 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 			unsigned write_max = chip.page_size;
 
+			at24->macc.write = at24_macc_write;
+
 			at24->bin.write = at24_bin_write;
 			at24->bin.attr.mode |= S_IWUSR;
 
@@ -480,11 +593,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 			at24->write_max = write_max;
 
 			/* buffer (data + address at the beginning) */
-			at24->writebuf = kmalloc(write_max + 2, GFP_KERNEL);
-			if (!at24->writebuf) {
-				err = -ENOMEM;
-				goto err_struct;
-			}
+			at24->writebuf = devm_kzalloc(&client->dev,
+				write_max + 2, GFP_KERNEL);
+			if (!at24->writebuf)
+				return -ENOMEM;
 		} else {
 			dev_warn(&client->dev,
 				"cannot write due to controller restrictions.");
@@ -511,14 +623,19 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	i2c_set_clientdata(client, at24);
 
-	dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
+	dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n",
 		at24->bin.size, client->name,
-		writable ? "(writable)" : "(read-only)");
-	dev_dbg(&client->dev,
-		"page_size %d, num_addresses %d, write_max %d%s\n",
-		chip.page_size, num_addresses,
-		at24->write_max,
-		use_smbus ? ", use_smbus" : "");
+		writable ? "writable" : "read-only", at24->write_max);
+	if (use_smbus == I2C_SMBUS_WORD_DATA ||
+	    use_smbus == I2C_SMBUS_BYTE_DATA) {
+		dev_notice(&client->dev, "Falling back to %s reads, "
+			   "performance will suffer\n", use_smbus ==
+			   I2C_SMBUS_WORD_DATA ? "word" : "byte");
+	}
+
+	/* export data to kernel code */
+	if (chip.setup)
+		chip.setup(&at24->macc, chip.context);
 
 	return 0;
 
@@ -527,15 +644,10 @@ err_clients:
 		if (at24->client[i])
 			i2c_unregister_device(at24->client[i]);
 
-	kfree(at24->writebuf);
-err_struct:
-	kfree(at24);
-err_out:
-	dev_dbg(&client->dev, "probe error %d\n", err);
 	return err;
 }
 
-static int __devexit at24_remove(struct i2c_client *client)
+static int at24_remove(struct i2c_client *client)
 {
 	struct at24_data *at24;
 	int i;
@@ -546,9 +658,6 @@ static int __devexit at24_remove(struct i2c_client *client)
 	for (i = 1; i < at24->num_addresses; i++)
 		i2c_unregister_device(at24->client[i]);
 
-	kfree(at24->writebuf);
-	kfree(at24);
-	i2c_set_clientdata(client, NULL);
 	return 0;
 }
 
@@ -560,12 +669,17 @@ static struct i2c_driver at24_driver = {
 		.owner = THIS_MODULE,
 	},
 	.probe = at24_probe,
-	.remove = __devexit_p(at24_remove),
+	.remove = at24_remove,
 	.id_table = at24_ids,
 };
 
 static int __init at24_init(void)
 {
+	if (!io_limit) {
+		pr_err("at24: io_limit must not be 0!\n");
+		return -EINVAL;
+	}
+
 	io_limit = rounddown_pow_of_two(io_limit);
 	return i2c_add_driver(&at24_driver);
 }