Using PXA arm board with MAX7319 GPIO expander input

[Eric Miao]

On Mon, Feb 8, 2010 at 1:44 PM, Jebediah Huang <jebediah.huang at gmail.com> wrote:
> Hello ,
>
> I have PXA166 board with MAX7319 GPIO expander connected with 8
> buttons. When any button is pressed, I want to get input event. Can
> this be done?
>
> I have read the littleton and aspenite code to try. The SDA is 105,
> SCL is 106. I use MAX732x driver. It is set as I2C slave at 0x6C. So I
> set up:
>
> static struct i2c_pxa_platform_data pwri2c_info __initdata = {
>        .use_pio                = 1,
> };
>
> static unsigned long peony_pin_config[] __initdata = {
>        /* i2c bus */
>        GPIO105_CI2C_SDA,
>        GPIO106_CI2C_SCL,
> }
>
> static struct max732x_platform_data max7319_data[] = {
>        [0] = {
>                .gpio_base      = GPIO_EXT0(0),
>        },
> };
>
> static struct i2c_board_info i2c_board_info[] =
> {
>        {
>                .type           = "max7319",
>                .addr           = 0x6C,
>                .irq            = IRQ_GPIO(105),

This doesn't look correct, if max7319 is ever able to interrupt the host
CPU, this should be something other than SDA.

However, this isn't supposed to be the reason for the failure. The
failure looks like an I2C communication issue to me, which means:

1. the i2c host driver isn't setup correctly
2. pin setup
3. max7319 power supply and chip select
4. i2c bus (incorrect pull-up/down etc)
5. i2c device address

I'd recommend an oscilloscope/LA for the I2C protocol on the lines
to identify the real issue.

>                .platform_data  = &max7319_data[0],
>        },
> };
>
> when bootup I see;
> <6>[    0.290770] I2C: i2c-0: PXA I2C adapter
> <6>[    0.307118] I2C: i2c-1: PXA I2C adapter
> <6>[    0.821709] hello pony_init
> <3>[    0.838559] platform_driver_register
> <6>[    0.868069] max732x_read: read g 1
> <6>[    0.881893] max732x_read: read g 0
> <4>[    0.898895] i2c: error: exhausted retries
> <4>[    0.911947] i2c: msg_num: 0 msg_idx: -2000 msg_ptr: 0
> <4>[    0.927509] i2c: ICR: 000007e0 ISR: 00000002
> <4>[    0.927526] i2c: log: [00000006:00000000] [00000006:00000000]
> [00000006:00000000] [00000006:00000000] [00000006:00000000]
> [00000006:00000000] [0000000
> <3>[    1.167890] dummy 0-005d: failed reading
> <5>[    1.182585] SCSI subsystem initialized
>
> Maybe max732x driver is not getting correct data from my setup? No
> event when pressing button. If any ideas?
>
> Thank you very much!
> Jeb
>
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