Re: Almost certainly confirmed, sun7i-a20 does not support 8 bit mmc.
From: Hans de Goede
Date: Wed Sep 09 2015 - 11:32:52 EST
Hi,
On 09-09-15 16:30, Maxime Ripard wrote:
On Wed, Sep 09, 2015 at 03:04:11PM +0200, Olliver Schinagl wrote:
Hey all,
After experimenting with a Micron eMMC chip, I made some interesting finds I
wanted to share with you all.
For a while now, some had hopes or guessed that the A20 could have support
for 8 bit wide bused on the SDC2. Reason for thinking this was, because the
sun7i uses the same IP as the sun5i which does support 8 bit wide eMMC. The
usermanual does mention 1/4/8 bit data buses and jedec 4.3 support of the
MMC spec. Unfortunately so far, it appears that the extra data pins have not
been muxed out to the PC pads.
I used the following code to enable the extra pins on the A20:
mmc2_pins_a: mmc2@0 {
- allwinner,pins = "PC6", "PC7", "PC8",
- "PC9", "PC10", "PC11";
+ allwinner,pins = "PC6", "PC7",
+ "PC8", "PC9", "PC10",
"PC11",
+ "PC12", "PC13", "PC14",
"PC15";
and
SUNXI_PIN(SUNXI_PINCTRL_PIN(C, 12),
SUNXI_FUNCTION(0x0, "gpio_in"),
SUNXI_FUNCTION(0x1, "gpio_out"),
- SUNXI_FUNCTION(0x2, "nand0")), /* NDQ4 */
+ SUNXI_FUNCTION(0x2, "nand0"), /* NDQ4 */
+ SUNXI_FUNCTION(0x3, "mmc2")), /* D4 */
SUNXI_PIN(SUNXI_PINCTRL_PIN(C, 13),
SUNXI_FUNCTION(0x0, "gpio_in"),
SUNXI_FUNCTION(0x1, "gpio_out"),
- SUNXI_FUNCTION(0x2, "nand0")), /* NDQ5 */
+ SUNXI_FUNCTION(0x2, "nand0"), /* NDQ5 */
+ SUNXI_FUNCTION(0x3, "mmc2")), /* D5 */
SUNXI_PIN(SUNXI_PINCTRL_PIN(C, 14),
SUNXI_FUNCTION(0x0, "gpio_in"),
SUNXI_FUNCTION(0x1, "gpio_out"),
- SUNXI_FUNCTION(0x2, "nand0")), /* NDQ6 */
+ SUNXI_FUNCTION(0x2, "nand0"), /* NDQ6 */
+ SUNXI_FUNCTION(0x3, "mmc2")), /* D6 */
SUNXI_PIN(SUNXI_PINCTRL_PIN(C, 15),
SUNXI_FUNCTION(0x0, "gpio_in"),
SUNXI_FUNCTION(0x1, "gpio_out"),
- SUNXI_FUNCTION(0x2, "nand0")), /* NDQ7 */
+ SUNXI_FUNCTION(0x2, "nand0"), /* NDQ7 */
+ SUNXI_FUNCTION(0x3, "mmc2")), /* D7 */
Where did you get that info from ? Those pins have never been reported
as having the mmc2 function, which would explain why it doesn't work.
Right, but the A20 has the same mmc controller as the A13, which does
do 8 bit mmc on PORTC, and the datasheet advertises 8 bit bus width
support in its feature list. So this was worth a shot.
Regards,
Hans
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