[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>

diff --git a/drivers/mtd/onenand/omap2.c b/drivers/mtd/onenand/omap2.c
index 40153ac..34b4253 100644 (file)
--- 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) {