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

[Stefan Agner <stefan@agner.ch>]

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 :-(

--
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@agner.ch>
>> ---
>> This addresses a regression ssen on v4.17-rc1 where the kernel
>> boots during clock initialization, see also:
>> https://patchwork.kernel.org/patch/10295927/
>>
>>  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
>>