Re: [alsa-devel] [PATCH v4 5/9] clk: at91: clk-generated: create function to find best_diff

On 25/07/2017 at 09:37, Quentin Schulz wrote:

The way to find the best_diff and do the appropriate process afterwards can be re-used.

This patch prepares the driver for an upcoming patch that will allow clk_generated to determine the rate of the audio_pll.

Signed-off-by: Quentin Schulz quentin.schulz@free-electrons.com Acked-by: Boris Brezillon boris.brezillon@free-electrons.com

Acked-by: Nicolas Ferre nicolas.ferre@microchip.com

---

drivers/clk/at91/clk-generated.c | 41 +++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c index ef4b4e0..7260e49 100644 --- a/drivers/clk/at91/clk-generated.c +++ b/drivers/clk/at91/clk-generated.c @@ -99,15 +99,36 @@ clk_generated_recalc_rate(struct clk_hw *hw, return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1); }

+static void clk_generated_best_diff(struct clk_rate_request *req,

• 		    struct clk_hw *parent,
  

• 		    unsigned long parent_rate, u32 div,
  

• 		    int *best_diff, long *best_rate)
  

+{

• unsigned long tmp_rate;
• int tmp_diff;
• if (!div)

• tmp_rate = parent_rate;
  

• else

• tmp_rate = parent_rate / div;
  

• tmp_diff = abs(req->rate - tmp_rate);
• if (*best_diff < 0 || *best_diff > tmp_diff) {

• *best_rate = tmp_rate;
  

• *best_diff = tmp_diff;
  

• req->best_parent_rate = parent_rate;
  

• req->best_parent_hw = parent;
  

• }

+}

static int clk_generated_determine_rate(struct clk_hw *hw, struct clk_rate_request *req) { struct clk_generated *gck = to_clk_generated(hw); struct clk_hw *parent = NULL; long best_rate = -EINVAL;

• unsigned long tmp_rate, min_rate;

• unsigned long min_rate; int best_diff = -1;

• int tmp_diff; int i;

  for (i = 0; i < clk_hw_get_num_parents(hw); i++) {

@@ -125,18 +146,10 @@ static int clk_generated_determine_rate(struct clk_hw *hw, continue;

div = DIV_ROUND_CLOSEST(parent_rate, req->rate);

• if (!div)
  

• 	tmp_rate = parent_rate;
  

• else
  

• 	tmp_rate = parent_rate / div;
  

• tmp_diff = abs(req->rate - tmp_rate);
  

• if (best_diff < 0 || best_diff > tmp_diff) {
  

• 	best_rate = tmp_rate;
  

• 	best_diff = tmp_diff;
  

• 	req->best_parent_rate = parent_rate;
  

• 	req->best_parent_hw = parent;
  

• }
  

• clk_generated_best_diff(req, parent, parent_rate, div,
  

• 			&best_diff, &best_rate);
  

• if (!best_diff) break;