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path: root/drivers/i2c/designware_i2c.c
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Diffstat (limited to 'drivers/i2c/designware_i2c.c')
-rw-r--r--drivers/i2c/designware_i2c.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c
index cb2ac04..9ed9295 100644
--- a/drivers/i2c/designware_i2c.c
+++ b/drivers/i2c/designware_i2c.c
@@ -266,6 +266,25 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
unsigned long start_time_rx;
+#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
+ /*
+ * EEPROM chips that implement "address overflow" are ones
+ * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
+ * address and the extra bits end up in the "chip address"
+ * bit slots. This makes a 24WC08 (1Kbyte) chip look like
+ * four 256 byte chips.
+ *
+ * Note that we consider the length of the address field to
+ * still be one byte because the extra address bits are
+ * hidden in the chip address.
+ */
+ chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
+ addr &= ~(CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW << (alen * 8));
+
+ debug("%s: fix addr_overflow: chip %02x addr %02x\n", __func__, chip,
+ addr);
+#endif
+
if (check_params(addr, alen, buffer, len))
return 1;
@@ -307,6 +326,25 @@ int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
int nb = len;
unsigned long start_time_tx;
+#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
+ /*
+ * EEPROM chips that implement "address overflow" are ones
+ * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
+ * address and the extra bits end up in the "chip address"
+ * bit slots. This makes a 24WC08 (1Kbyte) chip look like
+ * four 256 byte chips.
+ *
+ * Note that we consider the length of the address field to
+ * still be one byte because the extra address bits are
+ * hidden in the chip address.
+ */
+ chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
+ addr &= ~(CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW << (alen * 8));
+
+ debug("%s: fix addr_overflow: chip %02x addr %02x\n", __func__, chip,
+ addr);
+#endif
+
if (check_params(addr, alen, buffer, len))
return 1;