km/spi: overwrite kirkwood_spi weak functions for KM Kirkwood boards

As the SPI NOR and NAND devices share the same hardware pins, the MPP
configuration has to be changed when claiming/releasing the bus. The
current configuration is saved when claiming and restored when releasing.
Furthermore, a general-purpose output is used to switch the chip-select
signal. This is now also implemented for the DM part of the kirkwood_spi
driver.
Signed-off-by: NPascal Linder <pascal.linder@edu.hefr.ch>
Signed-off-by: NHolger Brunck <holger.brunck@ch.abb.com>
Signed-off-by: NStefan Roese <sr@denx.de>

board/keymile/km_arm/km_arm.c

@@ -322,6 +322,37 @@ void board_spi_release_bus(struct spi_slave *slave)
 	kw_gpio_set_value(KM_FLASH_GPIO_PIN, 1);
 }
 
+static const u32 spi_mpp_config[] = {
+	MPP1_SPI_MOSI,
+	MPP2_SPI_SCK,
+	MPP3_SPI_MISO,
+	0
+};
+
+static u32 spi_mpp_backup[4];
+
+int mvebu_board_spi_claim_bus(struct udevice *dev)
+{
+	spi_mpp_backup[3] = 0;
+
+	/* set new spi mpp config and save current one */
+	kirkwood_mpp_conf(spi_mpp_config, spi_mpp_backup);
+
+	kw_gpio_set_value(KM_FLASH_GPIO_PIN, 0);
+
+	return 0;
+}
+
+int mvebu_board_spi_release_bus(struct udevice *dev)
+{
+	/* restore saved mpp config */
+	kirkwood_mpp_conf(spi_mpp_backup, NULL);
+
+	kw_gpio_set_value(KM_FLASH_GPIO_PIN, 1);
+
+	return 0;
+}
+
 #if (defined(CONFIG_KM_PIGGY4_88E6061))
 
 #define	PHY_LED_SEL_REG		0x18