[PATCH u-boot-marvell v2] arm: a37xx: espressobin: Fix non-working SPI

[Pali Rohár]

Commit 0934dddc6436 ("arm: a37xx: Update DTS files to version from
upstream Linux kernel") ported Linux's device-tree files for Armada 3720
SOCs. This broke SPI support on some Espressobin boards and results in
following U-Boot error:

  Loading Environment from SPIFlash... jedec_spi_nor flash at 0: unrecognized JEDEC id bytes: f7, 30, 0b
  *** Warning - spi_flash_probe_bus_cs() failed, using default environment

Before that commit DT node for SPI was called 'spi-flash at 0' and after
that commit it is called 'flash at 0'. Before that commit 'spi-max-frequency'
was set to 50000000 and after it is 104000000.

Rename DT node 'spi-flash at 0 in armada-3720-espressobin-u-boot.dtsi to
'flash at 0' and set custom U-Boot 'spi-max-frequency' back to 50000000.

With this change SPI is working on Espressobin again and it is detected
with JEDEC ids ef, 60, 16 on our tested unit.

  Loading Environment from SPIFlash... SF: Detected w25q32dw with page size 256 Bytes, erase size 4 KiB, total 4 MiB
  OK

Note that it is unknown why spi-max-frequency with value 104000000 does not
work in U-Boot as it works fine with Linux kernel. Also note that in
defconfig file configs/mvebu_espressobin-88f3720_defconfig is set option
CONFIG_SF_DEFAULT_SPEED=40000000 which is different value than in DT.

Fixes: 0934dddc6436 ("arm: a37xx: Update DTS files to version from upstream Linux kernel")
Signed-off-by: Pali Rohár <pali at kernel.org>

---
Changes in v2:
* Fix #endif for partitions { } node
---
 arch/arm/dts/armada-3720-espressobin-u-boot.dtsi | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/arm/dts/armada-3720-espressobin-u-boot.dtsi b/arch/arm/dts/armada-3720-espressobin-u-boot.dtsi
index 3e01c64a4bdb..07293ab72d1f 100644
--- a/arch/arm/dts/armada-3720-espressobin-u-boot.dtsi
+++ b/arch/arm/dts/armada-3720-espressobin-u-boot.dtsi
@@ -1,8 +1,15 @@
 // SPDX-License-Identifier: (GPL-2.0+ OR MIT)
 
-#ifdef CONFIG_ENV_IS_IN_SPI_FLASH
 &spi0 {
-	spi-flash at 0 {
+	flash at 0 {
+		/*
+		 * For some unknown reason U-Boot SPI driver cannot access
+		 * SPI-NOR with higher frequency. Linux kernel SPI driver
+		 * does not have this problem.
+		 */
+		spi-max-frequency = <50000000>;
+
+#ifdef CONFIG_ENV_IS_IN_SPI_FLASH
 		partitions {
 			compatible = "fixed-partitions";
 			#address-cells = <1>;
@@ -18,9 +25,9 @@
 				label = "u-boot-env";
 			};
 		};
+#endif
 	};
 };
-#endif
 
 /*
  * U-Boot requires to have this eMMC node by default in "okay" status. U-Boot
-- 
2.20.1