Re: [PATCH] spi: Support high CS when using descriptors

[Janek Kotas <jank@xxxxxxxxxxx>]

Hi Linus,

> On 10 Jan 2019, at 15:25, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> On Thu, Jan 10, 2019 at 1:46 PM Janek Kotas <jank@xxxxxxxxxxx> wrote:
>>> On 10 Jan 2019, at 13:15, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
>>> 
>>> Janek, it'd be great if you could test this patch and
>>> confirm that it makes the DW driver tick again.
>>> 
>> 
>> Hi Linus,
>> 
>> The setup function works now and the Cadence driver is initialized:
>> at25 spi0.0: 1 KByte at25 eeprom, pagesize 16
>> 
>> However, the chip select signal is inverted.
>> The moment the SPI HW is initialized it goes low.
>> It is driven high during SPI transmissions.
> 
> Ouch! Which device tree file is this?

I’m using a custom one for out test system.
Here’s the SPI part:

spi0: spi@fd0b0000 {
    compatible = "cdns,spi-r1p6";
    reg = <0x0 0xfd0b0000 0x0 0x1000>;
    clock-names = "ref_clk", "pclk";
    clocks = <&sysclock>, <&sysclock>;
    interrupts = <0 4 IRQ_TYPE_LEVEL_HIGH>;
    interrupt-parent = <&gic>;
    num-cs = <4>;
    is-decoded-cs = <0>;
    #address-cells = <1>;
    #size-cells = <0>;

    eeprom@0 {
        compatible = "at,at25";
        reg = <0>;
        spi-max-frequency = <10000000>;
        /* spi-cpha; */
        /* spi-cpol; */
        pagesize = <16>;
        size = <1024>;
        address-width = <16>;
    };
};



> My intention was that of_gpio_flags_quirks() in
> drivers/gpio/gpiolib-of.c would activate and you would
> get a print like this in dmesg:
> 
> of_gpio_flags_quirks: enforce active low on chipselect handle

I haven’t seen that in my logs.

> But I'm on to it!
> 
> Yours,
> Linus Walleij

Regards,
Janek