From 679d446fde067d828e0bcc6883e4beccd52c3e9a Mon Sep 17 00:00:00 2001
From: Warner Losh <imp@FreeBSD.org>
Date: Tue, 31 Jul 2012 19:14:22 +0000
Subject: [PATCH] Allow chip selects other than 0.  The SAM9260EK board has its
 dataflash on CS1.

---
 sys/arm/at91/at91_spi.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/sys/arm/at91/at91_spi.c b/sys/arm/at91/at91_spi.c
index a81e0be64fce..f01e9845857d 100644
--- a/sys/arm/at91/at91_spi.c
+++ b/sys/arm/at91/at91_spi.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
 
 #include <machine/bus.h>
 
+#include <arm/at91/at91var.h>
 #include <arm/at91/at91_spireg.h>
 #include <arm/at91/at91_pdcreg.h>
 
@@ -144,6 +145,7 @@ at91_spi_attach(device_t dev)
 	 * memory and APB bandwidth.
 	 * Also, currently we lack a way for lettting both the board and the
 	 * slave devices take their maximum supported SPI clocks into account.
+	 * Also, we hard-wire SPI mode to 3.
 	 */
 	csr = SPI_CSR_CPOL | (4 << 16) | (0xff << 8);
 	WR4(sc, SPI_CSR0, csr);
@@ -285,7 +287,10 @@ at91_spi_transfer(device_t dev, device_t child, struct spi_command *cmd)
 	 */
 	WR4(sc, PDC_PTCR, PDC_PTCR_TXTDIS | PDC_PTCR_RXTDIS);
 
-#ifdef SPI_CHIPSEL_SUPPORT
+	/*
+	 * PSCDEC = 0 has a range of 0..3 for chip select.  We
+	 * don't support PSCDEC = 1 which has a range of 0..15.
+	 */
 	if (cmd->cs < 0 || cmd->cs > 3) {
 		device_printf(dev,
 		    "Invalid chip select %d requested by %s\n", cmd->cs,
@@ -293,18 +298,23 @@ at91_spi_transfer(device_t dev, device_t child, struct spi_command *cmd)
 		err = EINVAL;
 		goto out;
 	}
+
 #ifdef SPI_CHIP_SELECT_HIGH_SUPPORT
+	/*
+	 * The AT91RM9200 couldn't do CS high for CS 0.  Other chips can, but we
+	 * don't support that yet, or other spi modes.
+	 */
 	if (at91_is_rm92() && cmd->cs == 0 &&
 	    (cmd->flags & SPI_CHIP_SELECT_HIGH) != 0) {
 		device_printf(dev,
-		    "Invalid chip select high requested by %s\n",
+		    "Invalid chip select high requested by %s for cs 0.\n",
 		    device_get_nameunit(child));
 		err = EINVAL;
 		goto out;
 	}
 #endif
-	WR4(sc, SPI_MR, (RD4(sc, SPI_MR) & ~0x000f0000) | CS_TO_MR(cmd->cs));
-#endif
+	err = (RD4(sc, SPI_MR) & ~0x000f0000) | CS_TO_MR(cmd->cs);
+	WR4(sc, SPI_MR, err);
 
 	/*
 	 * Set up the TX side of the transfer.