Hi Jassi, On Tue, Aug 9, 2011 at 6:13 PM, Jassi Brar <jassisinghbrar@xxxxxxxxx> wrote: > On Tue, Aug 9, 2011 at 7:28 PM, Padmavathi Venna <padma.v@xxxxxxxxxxx> wrote: >> SPI driver is modified to lookup the bus clock using the >> alias name instead of getting clock name and clock >> number from platform data. > Cool. > >> Driver is modified to get the best source clock among the >> available source clocks for the required frequency. > I am not sure if this driver should be deciding which clock is 'best' for it. > Because ... > 1) Usually it's the board designer who decides which clock to run at > what speed based upon target device. So ideally, based upon use-case > the driver should simply get the 'best' clock from board via platform in a > format that is compliant to the 'generic clock api'. As per your comment I modified the code for board designer to supply the required list of source clocks. If this list is NULL then it uses the all available clock sources. I will resubmit this patch. > 2) We are not changing source clock rates(and we should not). > So the 'best' clock found, might still be way off in accuracy. And when we > can't anyway guarantee accuracy, why not leave the decision to > the board designer who might, say, select the source clock good enough > to be useful to more than one controller yet not absolutely accurate for any ? Yes. We are not getting the accurate frequency but we are able to get best frequency. > 3) It keeps enabled 3 unused clocks all the time. I modified the code to enable only the best source clock. I will resubmit this patch. > > >> diff --git a/drivers/spi/spi_s3c64xx.c b/drivers/spi/spi_s3c64xx.c >> index 8945e20..d7c979d 100644 >> --- a/drivers/spi/spi_s3c64xx.c >> +++ b/drivers/spi/spi_s3c64xx.c >> @@ -132,6 +132,9 @@ >> #define RXBUSY (1<<2) >> #define TXBUSY (1<<3) >> >> +#define MAX_SPI_BUS_CLK (4) >> +#define MAX_PSR (256) > > Btw, > > #define MAX_SPI_BUS_CLK 4 > #define MAX_PSR 256 > > is safe ... even safer than with two on! Modified. > -- > To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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