[PATCH] mtd: spi-nor: siliconkaiser: add support for sk25lp128

[Tom Fitzhenry]

Add support for the siliconkaiser sk25lp128 chip.

This is the flash chip used in the PinePhone Pro[0], found by physical
inspection of the board.[1]

I cannot find a datasheet, but this chip supports SFDP.

This patch depends on SNOR_ID3().[2]

https://lore.kernel.org/all/20220510140232.3519184-1-michael@walle.cc/

Tested done: checked that the Pinephone Pro boots when a ROM is written to
/dev/mtdblock0.

$ xxd -p /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
53464450060101ff00060110300000ff9d05010380000002ffffffffffff
ffffffffffffffffffffffffffffffffffffe520f9ffffffff0744eb086b
083b80bbfeffffffffff00ffffff44eb0c200f5210d800ff234ac90082d8
11c7cccd68467a757a75f7a2d55c4a422cfff030c080ffffffffffffffff
ffffffffffffffff501950169cf9c0648fecffff
$ md5sum /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
de4d6be54e479d60859b0ca8a0ee9216
/sys/bus/spi/devices/spi0.0/spi-nor/sfdp
$ cat /sys/bus/spi/devices/spi0.0/spi-nor/jedec_id
257018
$ cat /sys/bus/spi/devices/spi0.0/spi-nor/partname
sk25lp128
$ cat /sys/bus/spi/devices/spi0.0/spi-nor/manufacturer
siliconkaiser

0. https://wiki.pine64.org/wiki/PinePhone_Pro#Specifications
1. Thanks to https://github.com/Biktorgj for finding that.
2. "mtd: spi-nor: introduce SNOR_ID3()" https://lore.kernel.org/all/20220510140232.3519184-1-michael@walle.cc/

Link: https://lore.kernel.org/all/20220510140232.3519184-1-michael@walle.cc/
Signed-off-by: Tom Fitzhenry <tom at tom-fitzhenry.me.uk>
---
 drivers/mtd/spi-nor/Makefile        |  1 +
 drivers/mtd/spi-nor/core.c          |  1 +
 drivers/mtd/spi-nor/core.h          |  1 +
 drivers/mtd/spi-nor/siliconkaiser.c | 15 +++++++++++++++
 4 files changed, 18 insertions(+)
 create mode 100644 drivers/mtd/spi-nor/siliconkaiser.c

diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
index e347b435a038..314ac7773369 100644
--- a/drivers/mtd/spi-nor/Makefile
+++ b/drivers/mtd/spi-nor/Makefile
@@ -12,6 +12,7 @@ spi-nor-objs			+= intel.o
 spi-nor-objs			+= issi.o
 spi-nor-objs			+= macronix.o
 spi-nor-objs			+= micron-st.o
+spi-nor-objs			+= siliconkaiser.o
 spi-nor-objs			+= spansion.o
 spi-nor-objs			+= sst.o
 spi-nor-objs			+= winbond.o
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index fdde80d9f388..e542d3009915 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1624,6 +1624,7 @@ static const struct spi_nor_manufacturer *manufacturers[] = {
 	&spi_nor_issi,
 	&spi_nor_macronix,
 	&spi_nor_micron,
+	&spi_nor_siliconkaiser,
 	&spi_nor_st,
 	&spi_nor_spansion,
 	&spi_nor_sst,
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 87183cff3251..8997099f6c5e 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -625,6 +625,7 @@ extern const struct spi_nor_manufacturer spi_nor_intel;
 extern const struct spi_nor_manufacturer spi_nor_issi;
 extern const struct spi_nor_manufacturer spi_nor_macronix;
 extern const struct spi_nor_manufacturer spi_nor_micron;
+extern const struct spi_nor_manufacturer spi_nor_siliconkaiser;
 extern const struct spi_nor_manufacturer spi_nor_st;
 extern const struct spi_nor_manufacturer spi_nor_spansion;
 extern const struct spi_nor_manufacturer spi_nor_sst;
diff --git a/drivers/mtd/spi-nor/siliconkaiser.c b/drivers/mtd/spi-nor/siliconkaiser.c
new file mode 100644
index 000000000000..82bb6094caa9
--- /dev/null
+++ b/drivers/mtd/spi-nor/siliconkaiser.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/mtd/spi-nor.h>
+
+#include "core.h"
+
+static const struct flash_info siliconkaiser_nor_parts[] = {
+  { "sk25lp128", SNOR_ID3(0x257018) },
+};
+
+const struct spi_nor_manufacturer spi_nor_siliconkaiser = {
+	.name = "siliconkaiser",
+	.parts = siliconkaiser_nor_parts,
+	.nparts = ARRAY_SIZE(siliconkaiser_nor_parts),
+};
-- 
2.36.0