Re: [U-Boot] [PATCH] video: ipuv3_fb: skip IPU shutdown if IPU was not enabled before

Hi Stefano,

On Mon, 28 Aug 2017 18:54:39 +0200 Stefano Babic sbabic@denx.de wrote: ...

...

• /*

• * Check if IPU clock was enabled before. Won't access
  

• * IPU registers if clock is not enabled.
  

• */
  

• reg = readl(&mxc_ccm->CCGR3);
• if ((reg & MXC_CCM_CCGR3_IPU1_IPU_MASK) == 0)

• return;
  
  

It looks to me quite weak to simply check if clock is gated. On some board clock is gated even if IPU is not active. Do you have a way reading inside IPU itself ? Then we can better decide if it was really acrive. For example, checking if ipu_enable_channel() was called (and DMA registers are set).

we cannot access IPU registers when IPU clock is disabled (register access will hang the CPU).

Thanks, Anatolij