2022-01-24 19:40:47

by Taniya Das

Subject: [PATCH v1] clk: qcom: clk-rcg2: Update logic to calculate D value for RCG

The current implementation does not check for D value is within
the accepted range for a given M & N value. Update the logic to
calculate the final D value based on the range. While at it, add
support for 2/3 divider in frac_table_pixel.

Signed-off-by: Taniya Das <[email protected]>
---
drivers/clk/qcom/clk-rcg2.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index e1b1b426fae4..036c8071c07a 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -264,7 +264,7 @@ static int clk_rcg2_determine_floor_rate(struct clk_hw *hw,

static int __clk_rcg2_configure(struct clk_rcg2 *rcg, const struct freq_tbl *f)
{
- u32 cfg, mask;
+ u32 cfg, mask, d_val, not2d_val;
struct clk_hw *hw = &rcg->clkr.hw;
int ret, index = qcom_find_src_index(hw, rcg->parent_map, f->src);

@@ -283,8 +283,18 @@ static int __clk_rcg2_configure(struct clk_rcg2 *rcg, const struct freq_tbl *f)
if (ret)
return ret;

+ /* Calculate 2d value */
+ d_val = f->n;
+
+ if (d_val > ((f->n - f->m) * 2))
+ d_val = (f->n - f->m) * 2;
+ else if (d_val < f->m)
+ d_val = f->m;
+
+ not2d_val = ~d_val & mask;
+
ret = regmap_update_bits(rcg->clkr.regmap,
- RCG_D_OFFSET(rcg), mask, ~f->n);
+ RCG_D_OFFSET(rcg), mask, not2d_val);
if (ret)
return ret;
}
@@ -720,6 +730,7 @@ static const struct frac_entry frac_table_pixel[] = {
{ 2, 9 },
{ 4, 9 },
{ 1, 1 },
+ { 2, 3 },
{ }
};

--
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2022-01-24 20:39:23

by Stephen Boyd

Subject: Re: [PATCH v1] clk: qcom: clk-rcg2: Update logic to calculate D value for RCG

Quoting Taniya Das (2022-01-24 09:14:15)
> The current implementation does not check for D value is within
> the accepted range for a given M & N value. Update the logic to
> calculate the final D value based on the range. While at it, add
> support for 2/3 divider in frac_table_pixel.

Please split this into two patches (at the "while at it") and add
Fixes tag.