On Friday 02 December 2016 02:35 PM, Keerthy wrote:
Currently the divider selection logic blindly divides the parent_rate by the clk rate and gives the divider value for the divider clocks which do not have the CLK_SET_RATE_PARENT flag set. Add the clk divider table parsing to get the closest divider available in the table provided via Device tree. The code is pretty much taken from: drivers/clk/clk-divider.c. and used here to fix up the best divider selection logic.
A gentle ping on this patch. This applies cleanly on the next branch as on today. Let me know if this needs to be rebased.
- Keerthy
Signed-off-by: Keerthy <[email protected]> Reported-by: Richard Woodruff <[email protected]> --- drivers/clk/ti/divider.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/drivers/clk/ti/divider.c b/drivers/clk/ti/divider.c index b4e5de1..6bb8778 100644 --- a/drivers/clk/ti/divider.c +++ b/drivers/clk/ti/divider.c @@ -140,6 +140,35 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div) return true; } +static int _div_round_up(const struct clk_div_table *table, + unsigned long parent_rate, unsigned long rate) +{ + const struct clk_div_table *clkt; + int up = INT_MAX; + int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate); + + for (clkt = table; clkt->div; clkt++) { + if (clkt->div == div) + return clkt->div; + else if (clkt->div < div) + continue; + + if ((clkt->div - div) < (up - div)) + up = clkt->div; + } + + return up; +} + +static int _div_round(const struct clk_div_table *table, + unsigned long parent_rate, unsigned long rate) +{ + if (!table) + return DIV_ROUND_UP(parent_rate, rate); + + return _div_round_up(table, parent_rate, rate); +} + static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, unsigned long *best_parent_rate) { @@ -155,7 +184,7 @@ static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) { parent_rate = *best_parent_rate; - bestdiv = DIV_ROUND_UP(parent_rate, rate); + bestdiv = _div_round(divider->table, parent_rate, rate); bestdiv = bestdiv == 0 ? 1 : bestdiv; bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv; return bestdiv;
