Hi Jean-Michel, On Fri, Nov 02, 2018 at 02:35:26PM +0100, Jean-Michel Hautbois wrote: > Hi all, > > I have a custom board based on a sama5d3 chip. The SoC is connected to > 2 pef24628 SHDSL transceivers, the first one on ebi@40000000 and the > second one on ebi@50000000. > I tried to write a basic char driver, using request_mem_region and > ioremap but I can't read or write into the device. > I have to say that the driver is based on a proprietary one, and > tested years ago on a PowerPC board. > > Then, after looking into deeper details in the datasheet I understand > it is connected through EBI and it sounds not so easy :D. > > I would appreciate some help/pointers on this, as there is (at least, > I could find) few documentation on how to use it except for NAND > cases. > > I have something like that in my DTS, but not sure this is the correct > way to do it : > > ebi: ebi@10000000 { > pinctrl-0 = <&pinctrl_ebi_nand_addr>; > pinctrl-names = "default"; > status = "okay"; > > dsp0: pef24628@1 { > status = "okay"; > compatible = "intel,pef24628"; > #address-cells = <1>; > #size-cells = <1>; > reg = <0x1 0x0 0x8000>; > pinctrl-0 = <&pinctrl_dsp_cs1>; > }; > > dsp1: pef24628@2 { > status = "okay"; > compatible = "intel,pef24628"; > #address-cells = <1>; > #size-cells = <1>; > reg = <0x2 0x0 0x8000>; > pinctrl-0 = <&pinctrl_dsp_cs2>; > }; > > nand_controller: nand-controller { > status = "okay"; > > nand@3 { > reg = <0x3 0x0 0x2>; > atmel,rb = <0>; > nand-bus-width = <8>; > nand-ecc-mode = "hw"; > nand-ecc-strength = <4>; > nand-ecc-step-size = <512>; > nand-on-flash-bbt; > label = "atmel_nand"; > > partitions { > compatible = "fixed-partitions"; > #address-cells = <1>; > #size-cells = <1>; > [...] > }; > }; > }; > > The pinctrl for ebi should probably be changed however, I am wondering > how the (platform ?) driver can access the adress ? Should it parse > itself the parent, and find range, etc. Or is there an accessor for it > ?
At first look, your DT seems correct. You have nothing special to do, the usual platform_get_resource() and devm_ioremap_resource() calls are enough. The address translation should be done automatically according to ranges property. Another hint is to check and specify the signals timings. Regards Ludovic > > Maybe can I just manually toggle the CS GPIO, and don't try to make > anything more complex than what it should be ? The driver should not > be atmel dependant... > > Thanks ! > JM > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-ker...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel