Re: [PATCH v3 03/36] mtd: st_spi_fsm: Initialise and configure the FSM for normal working conditions

Brian Norris
2013-12-10T19:01:10Z

Hi Lee,

On Fri, Nov 29, 2013 at 12:18:52PM +0000, Lee Jones wrote:
> --- a/drivers/mtd/devices/st_spi_fsm.c
> +++ b/drivers/mtd/devices/st_spi_fsm.c
> @@ -25,11 +25,121 @@
>
> #include "st_spi_fsm.h"
>
> +static inline uint32_t stfsm_fifo_available(struct stfsm *fsm)
> +{
> + return (readl(fsm->base + SPI_FAST_SEQ_STA) >> 5) & 0x7f;
> +}
> +
> +static void stfsm_clear_fifo(struct stfsm *fsm)
> +{
> + uint32_t avail;
> +
> + for (;;) {
> + avail = stfsm_fifo_available(fsm);
> + if (!avail)
> + break;
> +
> + while (avail) {
> + readl(fsm->base + SPI_FAST_SEQ_DATA_REG);
> + avail--;
> + }
> + }
> +}
> +
> +static int stfsm_set_mode(struct stfsm *fsm, uint32_t mode)
> +{
> + int ret, timeout = 10;
> +
> + /* Wait for controller to accept mode change */
> + while(--timeout) {

s/while(/while (/

You should run your series through scripts/checkpatch.pl. There are a
number of small things to fixup in a few of your patches.

> + ret = readl(fsm->base + SPI_STA_MODE_CHANGE);
> + if (ret & 0x1)
> + break;
> + udelay(1);
> + }
> +
> + if (!timeout)
> + return -EBUSY;
> +
> + writel(mode, fsm->base + SPI_MODESELECT);
> +
> + return 0;
> +}
> +
> +static void stfsm_set_freq(struct stfsm *fsm, uint32_t spi_freq)
> +{
> + uint32_t emi_freq;
> + uint32_t clk_div;
> +
> + /* TODO: Make this dynamic */
> + emi_freq = STFSM_DEFAULT_EMI_FREQ;
> +
> + /*
> + * Calculate clk_div - values between 2 and 128
> + * Multiple of 2, rounded up
> + */
> + clk_div = 2*((emi_freq + (2*spi_freq - 1))/(2*spi_freq));

I think this can use the <linux/kerne.h> round_up() macro. Also, you're
missing some spacing. Possibly:

clk_div = 2 * round_up(emi_freq, 2 * spi_freq);

> + if (clk_div < 2)
> + clk_div = 2;
> + else if (clk_div > 128)
> + clk_div = 128;
> +
> + /*
> + * Determine a suitable delay for the IP to complete a change of
> + * direction of the FIFO. The required delay is related to the clock
> + * divider used. The following heuristics are based on empirical tests,
> + * using a 100MHz EMI clock.
> + */
> + if (clk_div <= 4)
> + fsm->fifo_dir_delay = 0;
> + else if (clk_div <= 10)
> + fsm->fifo_dir_delay = 1;
> + else
> + fsm->fifo_dir_delay = (clk_div + 9) / 10;

round_down()?

> +
> + dev_dbg(fsm->dev, "emi_clk = %uHZ, spi_freq = %uHZ, clk_div = %u\n",
> + emi_freq, spi_freq, clk_div);
> +
> + writel(clk_div, fsm->base + SPI_CLOCKDIV);
> +}

Brian