drivers/designware_i2c - add suppor of CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW

Since we agreed on legacy implementation of "eeprom_{read|write}"
(http://patchwork.ozlabs.org/patch/295825/) I had to fix/make it work
again DesignWare I2C driver for cases when 1 EEPROM IC fake I2C with
anumber of "built-in" ICs with different chip addresses.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Tom Rini <trini@ti.com>
cc: Armando Visconti <armando.visconti@st.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Cc: Heiko Schocher <hs@denx.de>
Cc: Vipin KUMAR <vipin.kumar@st.com>
Cc: Tom Rix <Tom.Rix@windriver.com>
Cc: Mischa Jonker <mjonker@synopsys.com>
Cc: Kuo-Jung Su <dantesu@faraday-tech.com>

diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c
index cb2ac04b609864412a8054888f3420bf35ca0287..9ed929521a8944dc870fc2eff546507632b6e86a 100644 (file)
--- 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;