[PATCH v2] clk: qcom: clk-rcg2: Add support for duty-cycle for RCG

[Taniya Das]

The root clock generators with MND divider has the capability to support
change in duty-cycle by updating the 'D'. Add the clock ops which would
check all the boundary conditions and enable setting the desired duty-cycle
as per the consumer.

Signed-off-by: Taniya Das <t...@codeaurora.org>
---
 drivers/clk/qcom/clk-rcg2.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index 42f13a2..aac6893 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -357,6 +357,46 @@ static int clk_rcg2_set_floor_rate_and_parent(struct 
clk_hw *hw,
        return __clk_rcg2_set_rate(hw, rate, FLOOR);
 }

+static int clk_rcg2_set_duty_cycle(struct clk_hw *hw, struct clk_duty *duty)
+{
+       struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+       u32 notn_m_val, n_val, m_val, d_val, not2d_val, mask, duty_per;
+       int ret;
+
+       if (!rcg->mnd_width)
+               return 0;
+
+       mask = BIT(rcg->mnd_width) - 1;
+
+       regmap_read(rcg->clkr.regmap, RCG_N_OFFSET(rcg), &notn_m_val);
+       regmap_read(rcg->clkr.regmap, RCG_M_OFFSET(rcg), &m_val);
+
+       n_val = (~(notn_m_val) + m_val) & mask;
+
+       duty_per = (duty->num * 100) / duty->den;
+
+       /* Calculate 2d value */
+       d_val = DIV_ROUND_CLOSEST(n_val * duty_per * 2, 100);
+
+        /* Check BIT WIDTHS OF 2d. If D is too big reduce Duty cycle. */
+       if (d_val > mask)
+               d_val = mask;
+
+       if ((d_val / 2) > (n_val - m_val))
+               d_val = (n_val - m_val) * 2;
+       else if ((d_val / 2) < (m_val / 2))
+               d_val = m_val;
+
+       not2d_val = ~d_val & mask;
+
+       ret = regmap_update_bits(rcg->clkr.regmap, RCG_D_OFFSET(rcg), mask,
+                                not2d_val);
+       if (ret)
+               return ret;
+
+       return update_config(rcg);
+}
+
 const struct clk_ops clk_rcg2_ops = {
        .is_enabled = clk_rcg2_is_enabled,
        .get_parent = clk_rcg2_get_parent,
@@ -365,6 +405,7 @@ const struct clk_ops clk_rcg2_ops = {
        .determine_rate = clk_rcg2_determine_rate,
        .set_rate = clk_rcg2_set_rate,
        .set_rate_and_parent = clk_rcg2_set_rate_and_parent,
+       .set_duty_cycle = clk_rcg2_set_duty_cycle,
 };
 EXPORT_SYMBOL_GPL(clk_rcg2_ops);

@@ -376,6 +417,7 @@ const struct clk_ops clk_rcg2_floor_ops = {
        .determine_rate = clk_rcg2_determine_floor_rate,
        .set_rate = clk_rcg2_set_floor_rate,
        .set_rate_and_parent = clk_rcg2_set_floor_rate_and_parent,
+       .set_duty_cycle = clk_rcg2_set_duty_cycle,
 };
 EXPORT_SYMBOL_GPL(clk_rcg2_floor_ops);

--
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