Re: [alsa-devel] [PATCH 06/20] OMAP: McBSP: Use appropriate value for startup delay

On Thu, 30 Jul 2009 15:49:29 +0300 Eduardo Valentin eduardo.valentin@nokia.com wrote:

--- a/arch/arm/plat-omap/mcbsp.c +++ b/arch/arm/plat-omap/mcbsp.c @@ -394,7 +394,8 @@ void omap_mcbsp_start(unsigned int id) w = OMAP_MCBSP_READ(io_base, SPCR1); OMAP_MCBSP_WRITE(io_base, SPCR1, w | 1);

• udelay(100);

• /* Worst case: CLKSRG*2 = 8000khz: (1/8000) * 2 * 2 usec */
• udelay(500);

Note: udelay(100) us used to wait at least 2 CLKSRG cycles (as stated in TRM).

Are you sure this change is necessary? CLKSRG is kind of master clock to McBSP so original stetson guessed (?) 100 us should be fine for all serial links where bit clock is higher than 20 kHz.