[PATCH v2 2/6] clk: qcom: clk-alpha-pll: Update set_rate for Zonda PLL

From: Satya Priya Kakitapalli
Date: Tue Jul 02 2024 - 11:52:06 EST


The Zonda PLL has a 16 bit signed alpha and in the cases where the alpha
value is greater than 0.5, the L value needs to be adjusted accordingly.
Thus update the logic for the same.

Also, fix zonda set_rate failure when PLL is disabled. Currently,
clk_zonda_pll_set_rate polls for the PLL to lock even if the PLL is
disabled. However, if the PLL is disabled then LOCK_DET will never
assert and we'll return an error. There is no reason to poll LOCK_DET
if the PLL is already disabled, so skip polling in this case.

Signed-off-by: Satya Priya Kakitapalli <quic_skakitap@xxxxxxxxxxx>
---
drivers/clk/qcom/clk-alpha-pll.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
index 6107c144c0f5..d2bef078588f 100644
--- a/drivers/clk/qcom/clk-alpha-pll.c
+++ b/drivers/clk/qcom/clk-alpha-pll.c
@@ -2061,6 +2061,18 @@ static void clk_zonda_pll_disable(struct clk_hw *hw)
regmap_write(regmap, PLL_OPMODE(pll), 0x0);
}

+static void zonda_pll_adjust_l_val(unsigned long rate, unsigned long prate, u32 *l)
+{
+ u64 remainder, quotient;
+
+ quotient = rate;
+ remainder = do_div(quotient, prate);
+ *l = quotient;
+
+ if ((remainder * 2) / prate)
+ *l = *l + 1;
+}
+
static int clk_zonda_pll_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long prate)
{
@@ -2077,9 +2089,15 @@ static int clk_zonda_pll_set_rate(struct clk_hw *hw, unsigned long rate,
if (ret < 0)
return ret;

+ if (a & BIT(15))
+ zonda_pll_adjust_l_val(rate, prate, &l);
+
regmap_write(pll->clkr.regmap, PLL_ALPHA_VAL(pll), a);
regmap_write(pll->clkr.regmap, PLL_L_VAL(pll), l);

+ if (!clk_hw_is_enabled(hw))
+ return 0;
+
/* Wait before polling for the frequency latch */
udelay(5);


--
2.25.1