[Question] Use mr25h40 in a custom DSDT ACPI table

[Flavio Suligoi <f.suligoi@xxxxxxx>]

Hi all,

I work on a custom x86 board. In this board I have to manage an MRAM chip mr25h40 (on the SPI bus).
I want to modify the DSDT ACPI table in the BIOS.
Unfortunately, the mr25h40 is not Jedec compatible, so, in my DSDT, if I use the classic:

{"compatible", "jedec,spi-nor"} 

the device drivers mtd and m25p80 are loaded, but obviously the MRAM is not initialized:

    Device (NVR0) {
	Name (_HID, "PRP0001")
	Name (_DDN, "Everspin MR25H40 MRAM")
	Name (_CRS, ResourceTemplate () {
		SpiSerialBus (
			0,                      // Chip select
			PolarityLow,            // Chip select is active low
			FourWireMode,           // Full duplex
			8,                      // Bits per word is 8 (byte)
			ControllerInitiated,    // Don't care
			10000000,               // 10 MHz
			ClockPolarityLow,       // SPI mode 0 ClockPolarityLow
			ClockPhaseFirst,        // SPI mode 0 ClockPhaseFirst
			"\\_SB.SPI1",           // SPI host controller
			0                       // Must be 0
		)
	})
	Name (_DSD, Package () {
		ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
		Package () {
			Package () {"compatible", "jedec,spi-nor"},
		}
	})
  }



Instead if I try to use:

Package () {"compatible", "mr25h40"}

obviously it doesn't work, because "mr25h40" is not in the m25p_of_table.
Does anyone have any ideas?

Thanks and best regards,

Flavio Suligoi



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