Slow spi_sync() on pxa2xx_spi

Hello.

On Thu, 2011-06-16 at 11:19, Stefan Schmidt wrote:

On Thu, 2011-06-16 at 16:34, Eric Miao wrote:

quoted

What is the SPI frequency?

I tried various settings in .max_speed_hz from the original 6.6 MHt to
10 MHz and 13MHz as maximum of the controller. Did also not change
anything for me.

That reminds me that after defining DEBUG in pxa2xx_spi it did always
report 13MHz to me. Need to have a look at it.

Either the debug statement or the setting is indeed wrong.

[    0.696759] spi spi1.0: 13000000 Hz actual, PIO
[    0.715760] spi spi3.0: 13000000 Hz actual, PIO

Which comes from this part of the driver (with #define DEBUG set):

        /* NOTE:  PXA25x_SSP _could_ use external clocking ... */
        if (!pxa25x_ssp_comp(drv_data))
                dev_dbg(&spi->dev, "%ld Hz actual, %s\n",
                        clk_get_rate(ssp->clk)
                                / (1 + ((chip->cr0 & SSCR0_SCR(0xfff)) >> 8)),
                        chip->enable_dma ? "DMA" : "PIO");
        else
                dev_dbg(&spi->dev, "%ld Hz actual, %s\n",
                        clk_get_rate(ssp->clk) / 2
                                / (1 + ((chip->cr0 & SSCR0_SCR(0x0ff)) >> 8)),
                        chip->enable_dma ? "DMA" : "PIO");

But the board file has this:

static struct spi_board_info spi_board_info[] __initdata = {
        {
                .modalias = "lis3l02dq",
                .max_speed_hz = 8000000,/* 8MHz max spi frequency at 3V */
                .bus_num = 1,
                .chip_select = 0,
                .controller_data = &staccel_chip_info,
                .irq = IRQ_GPIO(96),
        }, {
                .modalias = "cc2420",
//              .max_speed_hz = 6500000,
                .max_speed_hz = 10000000, /* 10MHz */
                .bus_num = 3,
                .chip_select = 0,
                .controller_data = &cc2420_info,
                .platform_data = &cc2420_pdata,

        },
};

Its neither 8MHz for spi1.0 nor 10MHz for spi3.0.

Adding some debug info shows me that the driver gets the data fine form the
platform data:
[    0.695770] spi spi1.0: chip->speed_hz: 8000000, spi->max_speed_hz: 8000000
[    0.695872] spi spi1.0: 13000000 Hz actual, PIO
[    0.714824] spi spi3.0: chip->speed_hz: 10000000, spi->max_speed_hz: 10000000
[    0.714929] spi spi3.0: 13000000 Hz actual, PIO

Thats directly above the chip->cr0 and chip->cr1 calculations. Is this just the
initial seeting and it gets overwritten before a transfer or is the speed
calculation wrong?

regards
Stefan Schmidt