Previous restore was lazy and only restored CHxCONF when it was needed by

a specific chip select.  This could cause occasional errors on an SPI bus
where multiple chip selects are in use.
Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/spi/omap2_mcspi.c

@@ -134,6 +134,7 @@ struct omap2_mcspi_cs {
 	void __iomem		*base;
 	unsigned long		phys;
 	int			word_len;
+	struct list_head	node;
 	/* Context save and restore shadow register */
 	u32			chconf0;
 };
@@ -145,6 +146,7 @@ struct omap2_mcspi_regs {
 	u32 sysconfig;
 	u32 modulctrl;
 	u32 wakeupenable;
+	struct list_head cs;
 };
 
 static struct omap2_mcspi_regs omap2_mcspi_ctx[OMAP2_MCSPI_MAX_CTRL];
@@ -255,6 +257,7 @@ static void omap2_mcspi_set_master_mode(struct spi_master *master)
 static void omap2_mcspi_restore_ctx(struct omap2_mcspi *mcspi)
 {
 	struct spi_master *spi_cntrl;
+	struct omap2_mcspi_cs *cs;
 	spi_cntrl = mcspi->master;
 
 	/* McSPI: context restore */
@@ -266,6 +269,10 @@ static void omap2_mcspi_restore_ctx(struct omap2_mcspi *mcspi)
 
 	mcspi_write_reg(spi_cntrl, OMAP2_MCSPI_WAKEUPENABLE,
 			omap2_mcspi_ctx[spi_cntrl->bus_num - 1].wakeupenable);
+
+	list_for_each_entry(cs, &omap2_mcspi_ctx[spi_cntrl->bus_num - 1].cs,
+			node)
+		__raw_writel(cs->chconf0, cs->base + OMAP2_MCSPI_CHCONF0);
 }
 static void omap2_mcspi_disable_clocks(struct omap2_mcspi *mcspi)
 {
@@ -714,6 +721,9 @@ static int omap2_mcspi_setup(struct spi_device *spi)
 		cs->phys = mcspi->phys + spi->chip_select * 0x14;
 		cs->chconf0 = 0;
 		spi->controller_state = cs;
+		/* Link this to context save list */
+		list_add_tail(&cs->node,
+			&omap2_mcspi_ctx[mcspi->master->bus_num - 1].cs);
 	}
 
 	if (mcspi_dma->dma_rx_channel == -1
@@ -736,10 +746,15 @@ static void omap2_mcspi_cleanup(struct spi_device *spi)
 {
 	struct omap2_mcspi	*mcspi;
 	struct omap2_mcspi_dma	*mcspi_dma;
+	struct omap2_mcspi_cs	*cs;
 
 	mcspi = spi_master_get_devdata(spi->master);
 	mcspi_dma = &mcspi->dma_channels[spi->chip_select];
 
+	/* Unlink controller state from context save list */
+	cs = spi->controller_state;
+	list_del(&cs->node);
+
 	kfree(spi->controller_state);
 
 	if (mcspi_dma->dma_rx_channel != -1) {
@@ -1104,6 +1119,7 @@ static int __init omap2_mcspi_probe(struct platform_device *pdev)
 
 	spin_lock_init(&mcspi->lock);
 	INIT_LIST_HEAD(&mcspi->msg_queue);
+	INIT_LIST_HEAD(&omap2_mcspi_ctx[master->bus_num - 1].cs);
 
 	mcspi->ick = clk_get(&pdev->dev, "ick");
 	if (IS_ERR(mcspi->ick)) {