RE: [PATCH v2 2/3] clk: xilinx: vcu: don't set pll_ref as parent of VCU(enc/dec) clocks

Hi Geert,

Thank for the review.

-----Original Message-----
From: Geert Uytterhoeven <geert@linux-m68k.org>
Sent: Friday, January 3, 2025 12:58 AM
To: Visavalia, Rohit <redacted>
Cc: mturquette@baylibre.com; sboyd@kernel.org; Simek, Michal
[off-list ref]; Sagar, Vishal [off-list ref];
javier.carrasco.cruz@gmail.com; geert+renesas@glider.be; u.kleine-
koenig@baylibre.com; linux-clk@vger.kernel.org; linux-arm-
kernel@lists.infradead.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] clk: xilinx: vcu: don't set pll_ref as parent of
VCU(enc/dec) clocks

Hi Rohit,

On Thu, Jan 2, 2025 at 6:04 PM Rohit Visavalia [off-list ref] wrote:

quoted

CCF will try to adjust parent clock to set desire clock frequency of
child clock. So if pll_ref is not a fixed-clock then while setting
rate of enc/dec clocks pll_ref may get change, which may make VCU

malfunction.

quoted

Signed-off-by: Rohit Visavalia <redacted>
---
Changes in v2:
  - none
  - Link to v1:
https://lore.kernel.org/linux-clk/20241226122023.3439559-3-rohit.visav
alia@amd.com
---
 drivers/clk/xilinx/xlnx_vcu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/xilinx/xlnx_vcu.c

b/drivers/clk/xilinx/xlnx_vcu.c index 88b3fd8250c2..c520ae1ba65e
100644

--- a/drivers/clk/xilinx/xlnx_vcu.c
+++ b/drivers/clk/xilinx/xlnx_vcu.c

@@ -547,7 +547,7 @@ static int xvcu_register_clock_provider(struct

xvcu_device *xvcu)

quoted

                return PTR_ERR(hw);
        xvcu->pll_post = hw;

-       parent_data[0].fw_name = "pll_ref";
+       parent_data[0].fw_name = "dummy_name";
        parent_data[1].hw = xvcu->pll_post;

        hws[CLK_XVCU_ENC_CORE] =

You completely ignored Stephen's comment, which suggests to not pas
CLK_SET_RATE_PARENT instead (see xvcu_clk_hw_register_leaf()).

Thanks for pointing this out. Let me take care this in v3 patch series.

Gr{oetje,eeting}s,

                       Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But when
I'm talking to journalists I just say "programmer" or something like that.
                               -- Linus Torvalds

Thanks
Rohit