Messages in this thread | | | Date | Wed, 23 Jan 2013 11:00:56 +0100 | From | Lars-Peter Clausen <> | Subject | Re: [PATCH] clk: Add axi-clkgen driver |
| |
On 01/22/2013 06:55 PM, Mike Turquette wrote: > Quoting Lars-Peter Clausen (2013-01-09 10:12:00) > <snip> >> +static void axi_clkgen_write(struct axi_clkgen *axi_clkgen, >> + unsigned int reg, unsigned int val) >> +{ >> + iowrite32(val, axi_clkgen->base + reg); > > Silly question: any reason to use this over readl()? This is more for > my understanding than a real criticism.
I think I read somewhere at some point that ioread{8,16,32} is preferred over write{b,h,l} in new code.
> >> +} >> + >> +static void axi_clkgen_read(struct axi_clkgen *axi_clkgen, >> + unsigned int reg, unsigned int *val) >> +{ >> + *val = ioread32(axi_clkgen->base + reg); > > Same as above, any reason to use this over writel?
Same answer.
> > <snip> >> +static unsigned long axi_clkgen_recalc_rate(struct clk_hw *clk_hw, >> + unsigned long parent_rate) >> +{ >> + struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw); >> + unsigned int d, m, dout; >> + unsigned int reg; >> + >> + axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_OUT1, ®); >> + dout = (reg & 0x3f) + ((reg >> 6) & 0x3f); >> + axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_DIV, ®); >> + d = (reg & 0x3f) + ((reg >> 6) & 0x3f); >> + axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_FB1, ®); >> + m = (reg & 0x3f) + ((reg >> 6) & 0x3f); >> + >> + if (d == 0 || dout == 0) >> + return 0; >> + >> + return parent_rate / d * m / dout; > > Any chance of overflow here? Maybe do_div should be used?
Not if all the parameters are within spec. But since this is on a slowpath I guess it does not hurt to use do_div.
Will send a v2.
Thanks for the review, - Lars
| |