[MTD] [OneNAND] OMAP3: add delay for GPIO

On OMAP3, the driver was occasionally not seeing the GPIO
interrupt.  Adding a small delay of one register read
eliminates the problem.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/mtd/onenand/omap2.c b/drivers/mtd/onenand/omap2.c
index 40153ace5df6..34b42533f4bb 100644
--- a/drivers/mtd/onenand/omap2.c
+++ b/drivers/mtd/onenand/omap2.c
@@ -141,8 +141,13 @@ static int omap2_onenand_wait(struct mtd_info *mtd, int state)
 
                 /* Turn interrupts on */
                 syscfg = read_reg(c, ONENAND_REG_SYS_CFG1);
-                syscfg |= ONENAND_SYS_CFG1_IOBE;
-                write_reg(c, syscfg, ONENAND_REG_SYS_CFG1);
+                if (!(syscfg & ONENAND_SYS_CFG1_IOBE)) {
+                        syscfg |= ONENAND_SYS_CFG1_IOBE;
+                        write_reg(c, syscfg, ONENAND_REG_SYS_CFG1);
+                        if (cpu_is_omap34xx())
+                                /* Add a delay to let GPIO settle */
+                                syscfg = read_reg(c, ONENAND_REG_SYS_CFG1);
+                }
 
                 INIT_COMPLETION(c->irq_done);
                 if (c->gpio_irq) {