| Message ID | 1391589458-28018-5-git-send-email-jjhiblot@traphandler.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi JJ, I guess you're commit message is wrong: you're optimizing set_rate not determine_rate. Best Regards, Boris On 05/02/2014 09:37, Jean-Jacques Hiblot wrote: > Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com> > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com> > --- > drivers/clk/at91/clk-programmable.c | 38 ++++++++----------------------------- > 1 file changed, 8 insertions(+), 30 deletions(-) > > diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c > index 7bcc725..62e2509 100644 > --- a/drivers/clk/at91/clk-programmable.c > +++ b/drivers/clk/at91/clk-programmable.c > @@ -139,43 +139,21 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate, > struct clk_programmable *prog = to_clk_programmable(hw); > struct at91_pmc *pmc = prog->pmc; > const struct clk_programmable_layout *layout = prog->layout; > - unsigned long best_rate = parent_rate; > - unsigned long best_diff; > - unsigned long new_diff; > - unsigned long cur_rate; > + unsigned long div = parent_rate / rate; > int shift = 0; > u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) & > ~(PROG_PRES_MASK << layout->pres_shift); > > - if (rate > parent_rate) > - return parent_rate; > - else > - best_diff = parent_rate - rate; > + if (!div) > + return -EINVAL; > > - if (!best_diff) { > - pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | shift); > - return 0; > - } > - > - for (shift = 1; shift < PROG_PRES_MASK; shift++) { > - cur_rate = parent_rate >> shift; > - > - if (cur_rate > rate) > - new_diff = cur_rate - rate; > - else > - new_diff = rate - cur_rate; > - > - if (!new_diff) > - break; > + shift = fls(div) - 1; > > - if (new_diff < best_diff) { > - best_diff = new_diff; > - best_rate = cur_rate; > - } > + if (div != (1<<shift)) > + return -EINVAL; > > - if (rate > cur_rate) > - break; > - } > + if (shift >= PROG_PRES_MASK) > + return -EINVAL; > > pmc_write(pmc, AT91_PMC_PCKR(prog->id), > tmp | (shift << layout->pres_shift));
diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c index 7bcc725..62e2509 100644 --- a/drivers/clk/at91/clk-programmable.c +++ b/drivers/clk/at91/clk-programmable.c @@ -139,43 +139,21 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate, struct clk_programmable *prog = to_clk_programmable(hw); struct at91_pmc *pmc = prog->pmc; const struct clk_programmable_layout *layout = prog->layout; - unsigned long best_rate = parent_rate; - unsigned long best_diff; - unsigned long new_diff; - unsigned long cur_rate; + unsigned long div = parent_rate / rate; int shift = 0; u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) & ~(PROG_PRES_MASK << layout->pres_shift); - if (rate > parent_rate) - return parent_rate; - else - best_diff = parent_rate - rate; + if (!div) + return -EINVAL; - if (!best_diff) { - pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | shift); - return 0; - } - - for (shift = 1; shift < PROG_PRES_MASK; shift++) { - cur_rate = parent_rate >> shift; - - if (cur_rate > rate) - new_diff = cur_rate - rate; - else - new_diff = rate - cur_rate; - - if (!new_diff) - break; + shift = fls(div) - 1; - if (new_diff < best_diff) { - best_diff = new_diff; - best_rate = cur_rate; - } + if (div != (1<<shift)) + return -EINVAL; - if (rate > cur_rate) - break; - } + if (shift >= PROG_PRES_MASK) + return -EINVAL; pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | (shift << layout->pres_shift));