Hello Trent and Andy, > From: Trent Piepho [mailto:tpiepho@xxxxxxxxxx] > Sent: Friday, July 27, 2018 2:02 AM > To: andy.shevchenko@xxxxxxxxx; Hayashibara, Keiji/林原 啓二 <hayashibara.keiji@xxxxxxxxxxxxx> > Subject: Re: [PATCH v2 2/2] spi: add SPI controller driver for UniPhier SoC > > On Thu, 2018-07-26 at 11:46 +0300, Andy Shevchenko wrote: > > > + > > > + /* > > > + * the supported rates are even numbers from 4 to 254. (4,6,8...254) > > > + * round up as we look for equal or less speed > > > + */ > > > + ckrat = DIV_ROUND_UP(clk_get_rate(priv->clk), speed); > > > + ckrat = roundup(ckrat, 2); > > > > ckrat += ckrat & 1; > > Either way, the compiler produces the same code: > > add r0, r0, #1 > bic r0, r0, #1 > > I.e., ckrat = (ckrat + 1) & ~1, one "add" and one "and". > > Might as well use the macro so it's clear. There is also round_up(x,y), which I believe is intended to be used > only with power of 2 values of y. I confirmed round_up() macro. This macro is optimized to power of 2 argument, and it matches to this case and clear. I will replace to round_up() macro. Thank you. ----------------- Best Regards, Keiji Hayashibara -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
