[PATCH v1] mtd: spi-nor: add ACPI support for non-JEDEC SPI-NOR

From: Flavio Suligoi
Date: Tue Jan 26 2021 - 09:40:25 EST


In a x86 machine, an additional device can be described
inside the BIOS ACPI tables.
For example, an I2C GPIO expander, a LED, etc.,
can be successfully declared in ACPI, so that the related
device driver can start automatically at the boot.

But for the SPI NOR devices, the ACPI description works
for JEDEC-compatible devices only.

For example, an Everspin MR25H40 MRAM device (non-JEDEC
compatible), declared using the following table,
does not work:

Scope (\_SB.SPI1)
{
Device (NVR0)
{
Name (_HID, "PRP0001")
Name (_DDN, "Everspin MR25H40 MRAM")
Name (_CRS, ResourceTemplate () {
SpiSerialBus (
1, // 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
ResourceConsumer,
,
)
})

Name (_DSD, Package () {
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package () {
Package () {"compatible", "mr25h40"},
}
})
}
}

To enable the detection of a non-JEDEC device described
in a BIOS ACPI table, it is necessary to add its id name
in the spi_nor_of_table structure.
With this change, all the SPI NOR devices (JEDEC and
non-JEDEC) can be detected by the kernel (and the above
example of ACPI table finally works).

Signed-off-by: Flavio Suligoi <f.suligoi@xxxxxxx>
---
drivers/mtd/spi-nor/core.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 6ae7d4c2d2b6..b6fb8b15c439 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -3755,6 +3755,19 @@ static const struct of_device_id spi_nor_of_table[] = {
* JEDEC READ ID opcode (0x9F). Use this, if possible.
*/
{ .compatible = "jedec,spi-nor" },
+ { .compatible = "m25p05-nonjedec" },
+ { .compatible = "m25p10-nonjedec" },
+ { .compatible = "m25p20-nonjedec" },
+ { .compatible = "m25p40-nonjedec" },
+ { .compatible = "m25p80-nonjedec" },
+ { .compatible = "m25p16-nonjedec" },
+ { .compatible = "m25p32-nonjedec" },
+ { .compatible = "m25p64-nonjedec" },
+ { .compatible = "m25p128-nonjedec" },
+ { .compatible = "mr25h128" },
+ { .compatible = "mr25h256" },
+ { .compatible = "mr25h10" },
+ { .compatible = "mr25h40" },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, spi_nor_of_table);
--
2.25.1