Subject: [PATCH 6/9] mtd: gpmi: simplify the setting DLL code

From: [email-masked] (Vikram Narayanan)
Date: Tue, 11 Sep 2012 23:38:16 +0530

Hello Huang Shijie,

On 9/11/2012 11:47 AM, Huang Shijie wrote:
> The setting DLL code is a little mess.
> Just simplify the code and the comments.
>
> Signed-off-by: Huang Shijie<[email-masked]>
> ---
>   drivers/mtd/nand/gpmi-nand/gpmi-lib.c |   22 +++++++++-------------
>   1 files changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> index 037438a..83c5573 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
> @@ -779,30 +779,26 @@ void gpmi_begin(struct gpmi_nand_data *this)
>   	writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_CLR);
>
>   	/* Clear out the DLL control fields. */
> -	writel(BM_GPMI_CTRL1_RDN_DELAY,   gpmi_regs + HW_GPMI_CTRL1_CLR);
> -	writel(BM_GPMI_CTRL1_HALF_PERIOD, gpmi_regs + HW_GPMI_CTRL1_CLR);
> +	reg = BM_GPMI_CTRL1_RDN_DELAY | BM_GPMI_CTRL1_HALF_PERIOD;
> +	writel(reg, gpmi_regs + HW_GPMI_CTRL1_CLR);
>
>   	/* If no sample delay is called for, return immediately. */
>   	if (!hw.sample_delay_factor)
>   		return;
>
> -	/* Configure the HALF_PERIOD flag. */
> -	if (hw.use_half_periods)
> -		writel(BM_GPMI_CTRL1_HALF_PERIOD,
> -						gpmi_regs + HW_GPMI_CTRL1_SET);
> +	/* Set RDN_DELAY or HALF_PERIOD. */
> +	reg = ((hw.use_half_periods) ? BM_GPMI_CTRL1_HALF_PERIOD : 0)
> +		| BF_GPMI_CTRL1_RDN_DELAY(hw.sample_delay_factor);
>
> -	/* Set the delay factor. */
> -	writel(BF_GPMI_CTRL1_RDN_DELAY(hw.sample_delay_factor),
> -						gpmi_regs + HW_GPMI_CTRL1_SET);
> +	writel(reg, gpmi_regs + HW_GPMI_CTRL1_SET);
>
> -	/* Enable the DLL. */
> +	/* At last, we enable the DLL. */
>   	writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_SET);
>
>   	/*
>   	 * After we enable the GPMI DLL, we have to wait 64 clock cycles before
> -	 * we can use the GPMI.
> -	 *
> -	 * Calculate the amount of time we need to wait, in microseconds.
> +	 * we can use the GPMI. Calculate the amount of time we need to wait,
> +	 * in microseconds.
>   	 */
>   	clock_period_in_ns = 1000000000 / clk_get_rate(r->clock[0]);

NSEC_PER_SEC macro in the above statement?

Don't curse me for commenting about the code that you've not written. As 
this patch does some cleanups, I'm suggesting this.

>   	dll_wait_time_in_us = (clock_period_in_ns * 64) / 1000;

Regards,
Vikram