Re: [PATCH 6/6] clk: qcom: Fix APSS PLL and RCG Configuration

On 13. 01. 2023. 16:20, Konrad Dybcio wrote:

On 13.01.2023 15:36, devi priya wrote:

quoted

Included CLK_IS_CRITICAL flag which helps to properly enable
the APSS PLL during bootup.

Please describe the issue and not only the user-visible impact it
makes. Does the PLL get shut down by clk_ignore_unused? Maybe you
would be interested in the sync_state changes that landed in recent
-next that may solve it for you?

I don't think it should be always-on, as you have an alternate source
for low power modes, adding CLK_IS_CRITICAL will keep the PLL enabled
even if you're not using it.

I have the same opinion, as this is working fine on IPQ6018 and IPQ8074
and I have not experienced any issues with it.

quoted

clk_rcg2_ops should be used for APSS clock RCG, as other ops
will not configure the RCG register

RCG register meaning RCG register*s*, meaning in this case M/N/D
which would be required for proper rate setting and not only input
switching (which arguably doesn't seem to be of much concern on a
single-parent clock)? This all is not obvious..

Same question from me as well, why do you need clk_rcg2_ops with
a dummy frequency table since this is just a mux using RCG2 control
bits?

Regards,
Robert

Konrad

quoted

Co-developed-by: Praveenkumar I <redacted>
Signed-off-by: Praveenkumar I <redacted>
Signed-off-by: devi priya <redacted>
---
  drivers/clk/qcom/apss-ipq-pll.c | 1 +
  drivers/clk/qcom/apss-ipq6018.c | 8 +++++++-
  2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/qcom/apss-ipq-pll.c b/drivers/clk/qcom/apss-ipq-pll.c
index dd0c01bf5a98..75486a124fcd 100644
--- a/drivers/clk/qcom/apss-ipq-pll.c
+++ b/drivers/clk/qcom/apss-ipq-pll.c

@@ -33,6 +33,7 @@ static struct clk_alpha_pll ipq_pll = {
  			},
  			.num_parents = 1,
  			.ops = &clk_alpha_pll_huayra_ops,
+			.flags = CLK_IS_CRITICAL,
  		},
  	},
  };

diff --git a/drivers/clk/qcom/apss-ipq6018.c b/drivers/clk/qcom/apss-ipq6018.c
index f2f502e2d5a4..0d0e7196a4dc 100644
--- a/drivers/clk/qcom/apss-ipq6018.c
+++ b/drivers/clk/qcom/apss-ipq6018.c

@@ -33,15 +33,21 @@ static const struct parent_map parents_apcs_alias0_clk_src_map[] = {
  	{ P_APSS_PLL_EARLY, 5 },
  };
  
+static const struct freq_tbl ftbl_apcs_alias0_clk_src[] = {
+	{ .src = P_APSS_PLL_EARLY, .pre_div = 1 },
+	{ }
+};
+
  static struct clk_rcg2 apcs_alias0_clk_src = {
  	.cmd_rcgr = 0x0050,
+	.freq_tbl = ftbl_apcs_alias0_clk_src,
  	.hid_width = 5,
  	.parent_map = parents_apcs_alias0_clk_src_map,
  	.clkr.hw.init = &(struct clk_init_data){
  		.name = "apcs_alias0_clk_src",
  		.parent_data = parents_apcs_alias0_clk_src,
  		.num_parents = ARRAY_SIZE(parents_apcs_alias0_clk_src),
-		.ops = &clk_rcg2_mux_closest_ops,
+		.ops = &clk_rcg2_ops,
  		.flags = CLK_SET_RATE_PARENT,
  	},
  };

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