[PATCH] clk: imx6ull: use OSC clock during AXI rate change

[Jacky Bai]

> Subject: Re: [PATCH] clk: imx6ull: use OSC clock during AXI rate change
> 
> Hi Jacky,
> 
> On 02.05.2018 09:38, Shawn Guo wrote:
> > Hi Jacky,
> >
> > Do you see this problem on i.MX6 ULL?  What's your take on Stefan's fix?
> 
> Any comment to this?
> 
> It is 4.17.0-rc4 is out and i.MX 6ULL is still broken :-(
> 
Hi Stefan,

I have tried two 6ULL board, I don't meet such issue. System can boot up successfully with commit 6f9575e55632 included.
Anyway, the change in this patch is ok for me. it is no harm to the BUS clock change flow.

Jacky
> --
> Stefan
> 
> >
> > Shawn
> >
> > On Wed, Apr 18, 2018 at 02:49:08PM +0200, Stefan Agner wrote:
> >> On i.MX6 ULL using PLL3 seems to cause a freeze when setting the
> >> parent to IMX6UL_CLK_PLL3_USB_OTG. This only seems to appear since
> >> commit 6f9575e55632 ("clk: imx: Add CLK_IS_CRITICAL flag for busy
> >> divider and busy mux"), probably because the clock is now forced to
> >> be on.
> >>
> >> Fixes: 6f9575e55632("clk: imx: Add CLK_IS_CRITICAL flag for busy
> >> divider and busy mux")
> >> Signed-off-by: Stefan Agner <stefan at agner.ch>
> >> ---
> >> This addresses a regression ssen on v4.17-rc1 where the kernel boots
> >> during clock initialization, see also:
> >>
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpa
> >>
> tchwork.kernel.org%2Fpatch%2F10295927%2F&data=02%7C01%7Cping.bai%
> 40nx
> >>
> p.com%7C023287ec65034c4db45f08d5b419effb%7C686ea1d3bc2b4c6fa92cd9
> 9c5c
> >>
> 301635%7C0%7C0%7C636612945852594725&sdata=U0ZGid9ZBey0FXfId2dhZb
> hVl8p
> >> CcjTiexG3JHYwCA4%3D&reserved=0
> >>
> >>  drivers/clk/imx/clk-imx6ul.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/clk/imx/clk-imx6ul.c
> >> b/drivers/clk/imx/clk-imx6ul.c index 114ecbb94ec5..12320118f8de
> >> 100644
> >> --- a/drivers/clk/imx/clk-imx6ul.c
> >> +++ b/drivers/clk/imx/clk-imx6ul.c
> >> @@ -464,7 +464,7 @@ static void __init imx6ul_clocks_init(struct
> device_node *ccm_node)
> >>  	clk_set_rate(clks[IMX6UL_CLK_AHB], 99000000);
> >>
> >>  	/* Change periph_pre clock to pll2_bus to adjust AXI rate to 264MHz
> */
> >> -	clk_set_parent(clks[IMX6UL_CLK_PERIPH_CLK2_SEL],
> clks[IMX6UL_CLK_PLL3_USB_OTG]);
> >> +	clk_set_parent(clks[IMX6UL_CLK_PERIPH_CLK2_SEL],
> >> +clks[IMX6UL_CLK_OSC]);
> >>  	clk_set_parent(clks[IMX6UL_CLK_PERIPH],
> clks[IMX6UL_CLK_PERIPH_CLK2]);
> >>  	clk_set_parent(clks[IMX6UL_CLK_PERIPH_PRE],
> clks[IMX6UL_CLK_PLL2_BUS]);
> >>  	clk_set_parent(clks[IMX6UL_CLK_PERIPH],
> >> clks[IMX6UL_CLK_PERIPH_PRE]);
> >> --
> >> 2.17.0
> >>