Hello Shawn, many thanks for the patch review, I really appreciate it ! On Wed, Dec 5, 2018 at 2:52 AM Shawn Guo <shawnguo@xxxxxxxxxx> wrote: > > On Fri, Nov 30, 2018 at 03:56:23PM -0500, thesven73@xxxxxxxxx wrote: > > From: Sven Van Asbroeck <TheSven73@xxxxxxxxxxxxxx> > > > > Ensure that timing values for the child node are applied to > > all chip selects in the child's address ranges. > > > > I'm not sure about that. Shouldn't we have another child node for > different chip select, something like below? > > &weim { > acme@0,0 { > compatible = "acme,whatever"; > reg = <0 0 0x100>, <0 0x400000 0x800>; > fsl,weim-cs-timing = <0x024400b1 0x00001010 0x20081100 > 0x00000000 0xa0000240 0x00000000>; > }; > > acme@1,400000 { > compatible = "acme,whatever"; > reg = <1 0x400000 0x800>; > fsl,weim-cs-timing = <0x024400b1 0x00001010 0x20081100 > 0x00000000 0xa0000240 0x00000000>; > }; > > Shawn I am submitting patches for a device that spans chip selects :( And such a device needs multiple address changes with different chip selects. Imagine we have an acme device, which contains a control and a fifo region, on different chip selects: &weim { acme@0 { compatible = "acme"; reg = <0 0x0 0x100>, <1 0x0 0x100>; }; }; Now in probe we can access both regions: int acme_probe(struct platform_device *pdev) { control_res = platform_get_resource(pdev, IORESOURCE_MEM, 0); fifo_res = platform_get_resource(pdev, IORESOURCE_MEM, 1); /* all ok */ } But, if we have two separate child nodes, we also get two calls to probe(), which assumes two devices on the bus, and that is incorrect: &weim { acme@0 { compatible = "acme"; reg = <0 0x0 0x100>; }; acme@1 { compatible = "acme"; reg = <1 0x0 0x100>; }; }; int acme_probe(struct platform_device *pdev) { control_res = platform_get_resource(pdev, IORESOURCE_MEM, 0); /* next call always fails */ fifo_res = platform_get_resource(pdev, IORESOURCE_MEM, 1); } For my patchset, Rob Herring suggested I made changes to the imx-weim driver to accommodate multi-chipselect devices. See the conversation below between Rob Herring and myself: https://lkml.org/lkml/2018/11/30/390 If you are not entirely satisfied with my patch, then perhaps you could think of another way to support multi-chipselect devices? Many thanks, Sven