i2c_eeprom: Add reading support

This patch implements the reading functionality for the generic I2C
EEPROM driver, which was just a non-functional stub until now.

Since the page size will be of importance for the writing support, we
add suitable members to the private data structure to keep track of it.

Compatibility strings for a range of at24c* chips are added.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>

drivers/misc/Kconfig

@@ -144,4 +144,9 @@ config QFW
 	  Hidden option to enable QEMU fw_cfg interface. This will be selected by
 	  either CONFIG_CMD_QFW or CONFIG_GENERATE_ACPI_TABLE.
 
+config I2C_EEPROM
+	bool "Enable driver for generic I2C-attached EEPROMs"
+	depends on MISC
+	help
+	  Enable a generic driver for EEPROMs attached via I2C.
 endmenu

drivers/misc/i2c_eeprom.c

@@ -13,7 +13,7 @@
 static int i2c_eeprom_read(struct udevice *dev, int offset, uint8_t *buf,
 			   int size)
 {
-	return -ENODEV;
+	return dm_i2c_read(dev, offset, buf, size);
 }
 
 static int i2c_eeprom_write(struct udevice *dev, int offset,
@@ -27,23 +27,46 @@ struct i2c_eeprom_ops i2c_eeprom_std_ops = {
 	.write	= i2c_eeprom_write,
 };
 
+static int i2c_eeprom_std_ofdata_to_platdata(struct udevice *dev)
+{
+	struct i2c_eeprom *priv = dev_get_priv(dev);
+	u64 data = dev_get_driver_data(dev);
+
+	/* 6 bit -> page size of up to 2^63 (should be sufficient) */
+	priv->pagewidth = data & 0x3F;
+	priv->pagesize = (1 << priv->pagewidth);
+
+	return 0;
+}
+
 int i2c_eeprom_std_probe(struct udevice *dev)
 {
 	return 0;
 }
 
 static const struct udevice_id i2c_eeprom_std_ids[] = {
-	{ .compatible = "i2c-eeprom" },
+	{ .compatible = "i2c-eeprom", .data = 0 },
+	{ .compatible = "atmel,24c01a", .data = 3 },
+	{ .compatible = "atmel,24c02", .data = 3 },
+	{ .compatible = "atmel,24c04", .data = 4 },
+	{ .compatible = "atmel,24c08a", .data = 4 },
+	{ .compatible = "atmel,24c16a", .data = 4 },
+	{ .compatible = "atmel,24c32", .data = 5 },
+	{ .compatible = "atmel,24c64", .data = 5 },
+	{ .compatible = "atmel,24c128", .data = 6 },
+	{ .compatible = "atmel,24c256", .data = 6 },
+	{ .compatible = "atmel,24c512", .data = 6 },
 	{ }
 };
 
 U_BOOT_DRIVER(i2c_eeprom_std) = {
-	.name		= "i2c_eeprom",
-	.id		= UCLASS_I2C_EEPROM,
-	.of_match	= i2c_eeprom_std_ids,
-	.probe		= i2c_eeprom_std_probe,
-	.priv_auto_alloc_size = sizeof(struct i2c_eeprom),
-	.ops		= &i2c_eeprom_std_ops,
+	.name			= "i2c_eeprom",
+	.id			= UCLASS_I2C_EEPROM,
+	.of_match		= i2c_eeprom_std_ids,
+	.probe			= i2c_eeprom_std_probe,
+	.ofdata_to_platdata	= i2c_eeprom_std_ofdata_to_platdata,
+	.priv_auto_alloc_size	= sizeof(struct i2c_eeprom),
+	.ops			= &i2c_eeprom_std_ops,
 };
 
 UCLASS_DRIVER(i2c_eeprom) = {

include/i2c_eeprom.h

@@ -14,6 +14,10 @@ struct i2c_eeprom_ops {
 };
 
 struct i2c_eeprom {
+	/* The EEPROM's page size in byte */
+	unsigned long pagesize;
+	/* The EEPROM's page width in bits (pagesize = 2^pagewidth) */
+	unsigned pagewidth;
 };
 
 #endif