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Date: Thu, 01 Oct 2015 08:20:12 +0300
From: Vladimir Zapolskiy <vz@mleia.com>
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Subject: Re: [PATCH v2 1/3] mtd: nand: lpc32xx_slc: improve SLCTAC_*() macro
 definitions
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On 01.10.2015 02:23, Vladimir Zapolskiy wrote:
> No functional change, move bitfield calculations to macro
> definitions with added clock rate argument, which are in turn defined
> by new common SLCTAC_CLOCKS(c, n, s) macro definition.
> 
> Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
> ---
> Changes from v1 to v2:
> * none, new change
> 
>  drivers/mtd/nand/lpc32xx_slc.c | 27 +++++++++++++++------------
>  1 file changed, 15 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mtd/nand/lpc32xx_slc.c b/drivers/mtd/nand/lpc32xx_slc.c
> index abfec13..9ac0f3b 100644
> --- a/drivers/mtd/nand/lpc32xx_slc.c
> +++ b/drivers/mtd/nand/lpc32xx_slc.c
> @@ -94,22 +94,25 @@
>  /**********************************************************************
>  * slc_tac register definitions
>  **********************************************************************/
> +/* Computation of clock cycles on basis of controller and device clock rates */
> +#define SLCTAC_CLOCKS(c, n, s)	(((1 + (c / n)) & 0xF) << s)
> +
>  /* Clock setting for RDY write sample wait time in 2*n clocks */
>  #define SLCTAC_WDR(n)		(((n) & 0xF) << 28)
>  /* Write pulse width in clock cycles, 1 to 16 clocks */
> -#define SLCTAC_WWIDTH(n)	(((n) & 0xF) << 24)
> +#define SLCTAC_WWIDTH(c, n)	(SLCTAC_CLOCKS(c, n, 24))
>  /* Write hold time of control and data signals, 1 to 16 clocks */
> -#define SLCTAC_WHOLD(n)		(((n) & 0xF) << 20)
> +#define SLCTAC_WHOLD(c, n)	(SLCTAC_CLOCKS(c, n, 20))
>  /* Write setup time of control and data signals, 1 to 16 clocks */
> -#define SLCTAC_WSETUP(n)	(((n) & 0xF) << 16)
> +#define SLCTAC_WSETUP(c, n)	(SLCTAC_CLOCKS(c, n, 16))
>  /* Clock setting for RDY read sample wait time in 2*n clocks */
>  #define SLCTAC_RDR(n)		(((n) & 0xF) << 12)
>  /* Read pulse width in clock cycles, 1 to 16 clocks */
> -#define SLCTAC_RWIDTH(n)	(((n) & 0xF) << 8)
> +#define SLCTAC_RWIDTH(c, n)	(SLCTAC_CLOCKS(c, n, 8))
>  /* Read hold time of control and data signals, 1 to 16 clocks */
> -#define SLCTAC_RHOLD(n)		(((n) & 0xF) << 4)
> +#define SLCTAC_RHOLD(c, n)	(SLCTAC_CLOCKS(c, n, 4))
>  /* Read setup time of control and data signals, 1 to 16 clocks */
> -#define SLCTAC_RSETUP(n)	(((n) & 0xF) << 0)
> +#define SLCTAC_RSETUP(c, n)	(SLCTAC_CLOCKS(c, n, 0))
>  

Anticipating a question about not parenthesized arguments, I don't know,
if more parentheses around arguments in these macro definitions are
needed, because there is no other potential usage of them.
Please let me know, if you think different, I'll fix it.

--
With best wishes,
Vladimir