Hi Stephen, On Fri, Jul 1, 2016 at 11:38 AM, Stephen Boyd <sb...@codeaurora.org> wrote: > Sorry I replied offlist before. Pressed the wrong key. > > On 06/30, Hoan Tran wrote: >> On Thu, Jun 30, 2016 at 1:23 PM, Stephen Boyd <sb...@codeaurora.org> wrote: >> > >> > How is this different from clk-fractional-divider.c? >> > >> >> This is a driver which clock output is multiplied with a fixed fractional >> scale (denominator). >> A field inside a register is used to configure the multiplier. >> >> Example: With fractional scale is 1/8. >> Freq_out = Freq_parent * multiplier * (1/8) >> >> For fractional-divider, there are 2 fields of a register are used which >> - A field for numerator >> - A field for denominator >> Freq_out = Freq_parent * numerator / denominator >> > > Ok so the difference is that the denominator is a fixed value?
The major difference is a fixed denominator. Another difference is: In case CLK_FRACTIONAL_SCALE_INVERTED=1, the freq_out is calculated as below Freq_out = Freq_parent * (fixed_denominator - multiplier) / fixed_denominator. > Perhaps that can be modeled as a clk-multiplier that is used as > the only parent of a fixed divider? Because of CLK_FRACTIONAL_SCALE_INVERTED flag, I don't know how to model as a clk-multiplier. And how to pass the fixed denominator into a clk-multiplier. > Or we can add a flag to the > clk-fractional-divider code to handle this minor difference. This driver is used 2 register fields for numerator, denominator and calculates both of them. Do you think I can integrate this fractional scale into it ? Thanks Hoan > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > a Linux Foundation Collaborative Project
