Messages in this thread | | | Subject | Re: Almost certainly confirmed, sun7i-a20 does not support 8 bit mmc. | From | Hans de Goede <> | Date | Wed, 9 Sep 2015 17:32:42 +0200 |
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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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