spi: aspeed: Add support for the AST2400 SPI controller

Extend the driver for the AST2400 SPI Flash Controller (SPI). This
controller has a slightly different interface which requires
adaptation of the 4B handling. Summary of features :

   . host Firmware
   . 1 chip select pin (CE0)
   . slightly different register set, between AST2500 and the legacy
     controller
   . no segment registers
   . single, dual mode.

Reviewed-by: Joel Stanley <[email protected]>
Tested-by: Joel Stanley <[email protected]>
Tested-by: Tao Ren <[email protected]>
Tested-by: Jae Hyun Yoo <[email protected]>
Signed-off-by: Cédric Le Goater <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: legoater

drivers/spi/spi-aspeed-smc.c

@@ -30,6 +30,7 @@
 #define   CTRL_IO_DUAL_DATA		BIT(29)
 #define   CTRL_IO_QUAD_DATA		BIT(30)
 #define   CTRL_COMMAND_SHIFT		16
+#define   CTRL_IO_ADDRESS_4B		BIT(13)	/* AST2400 SPI only */
 #define   CTRL_IO_DUMMY_SET(dummy)					\
 	(((((dummy) >> 2) & 0x1) << 14) | (((dummy) & 0x3) << 6))
 #define   CTRL_CE_STOP_ACTIVE		BIT(2)
@@ -280,6 +281,8 @@ static bool aspeed_spi_supports_op(struct spi_mem *mem, const struct spi_mem_op
 	return spi_mem_default_supports_op(mem, op);
 }
 
+static const struct aspeed_spi_data ast2400_spi_data;
+
 static int do_aspeed_spi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 {
 	struct aspeed_spi *aspi = spi_controller_get_devdata(mem->spi->master);
@@ -309,6 +312,9 @@ static int do_aspeed_spi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o
 			addr_mode |= (0x11 << chip->cs);
 		else
 			addr_mode &= ~(0x11 << chip->cs);
+
+		if (op->addr.nbytes == 4 && chip->aspi->data == &ast2400_spi_data)
+			ctl_val |= CTRL_IO_ADDRESS_4B;
 	}
 
 	if (op->dummy.nbytes)
@@ -398,7 +404,13 @@ static int aspeed_spi_chip_set_default_window(struct aspeed_spi_chip *chip)
 	struct aspeed_spi_window windows[ASPEED_SPI_MAX_NUM_CS] = { 0 };
 	struct aspeed_spi_window *win = &windows[chip->cs];
 
-	aspeed_spi_get_windows(aspi, windows);
+	/* No segment registers for the AST2400 SPI controller */
+	if (aspi->data == &ast2400_spi_data) {
+		win->offset = 0;
+		win->size = aspi->ahb_window_size;
+	} else {
+		aspeed_spi_get_windows(aspi, windows);
+	}
 
 	chip->ahb_base = aspi->ahb_base + win->offset;
 	chip->ahb_window_size = win->size;
@@ -461,6 +473,10 @@ static int aspeed_spi_chip_adjust_window(struct aspeed_spi_chip *chip,
 	struct aspeed_spi_window *win = &windows[chip->cs];
 	int ret;
 
+	/* No segment registers for the AST2400 SPI controller */
+	if (aspi->data == &ast2400_spi_data)
+		return 0;
+
 	/*
 	 * Due to an HW issue on the AST2500 SPI controller, the CE0
 	 * window size should be smaller than the maximum 128MB.
@@ -545,6 +561,12 @@ static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc)
 		else
 			addr_mode &= ~(0x11 << chip->cs);
 		writel(addr_mode, aspi->regs + CE_CTRL_REG);
+
+		/* AST2400 SPI controller sets 4BYTE address mode in
+		 * CE0 Control Register
+		 */
+		if (op->addr.nbytes == 4 && chip->aspi->data == &ast2400_spi_data)
+			ctl_val |= CTRL_IO_ADDRESS_4B;
 	}
 
 	/* READ mode is the controller default setting */
@@ -816,6 +838,14 @@ static const struct aspeed_spi_data ast2400_fmc_data = {
 	.segment_reg   = aspeed_spi_segment_reg,
 };
 
+static const struct aspeed_spi_data ast2400_spi_data = {
+	.max_cs	       = 1,
+	.hastype       = false,
+	.we0	       = 0,
+	.ctl0	       = 0x04,
+	/* No segment registers */
+};
+
 static const struct aspeed_spi_data ast2500_fmc_data = {
 	.max_cs	       = 3,
 	.hastype       = true,
@@ -860,6 +890,7 @@ static const struct aspeed_spi_data ast2600_spi_data = {
 
 static const struct of_device_id aspeed_spi_matches[] = {
 	{ .compatible = "aspeed,ast2400-fmc", .data = &ast2400_fmc_data },
+	{ .compatible = "aspeed,ast2400-spi", .data = &ast2400_spi_data },
 	{ .compatible = "aspeed,ast2500-fmc", .data = &ast2500_fmc_data },
 	{ .compatible = "aspeed,ast2500-spi", .data = &ast2500_spi_data },
 	{ .compatible = "aspeed,ast2600-fmc", .data = &ast2600_fmc_data },