[PATCH 04/39] ARM: OMAP2+: gpmc: Acquire NAND CS value

[Afzal Mohammed]

Some boards depend on bootloader to update chip select value for NAND.
It is felt that Kernel should not depend on bootloader to get CS, as
for a particular board CS is hardwired and is fixed, hence this can
directly be updated in Kernel. But as CS value for boards that depend
on this behaviour is not available, educate gpmc driver to acquire
chip select value for NAND. this ideally should be removed once CS
for those boards are available.

Signed-off-by: Afzal Mohammed <afzal at ti.com>
---
 arch/arm/mach-omap2/gpmc.c |   32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 657ce95..ecd3384 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -892,6 +892,30 @@ static int __init gpmc_init(void)
 }
 postcore_initcall(gpmc_init);
 
+static __devinit int gpmc_acquire_nand_cs(struct gpmc *gpmc,
+					struct gpmc_device_pdata *gdp)
+{
+	int cs = 0;
+	struct omap_nand_platform_data *nand = gdp->pdata;
+
+	if ((nand->cs >= 0) && (nand->cs < GPMC_CS_NUM))
+		return 0;
+
+	while (cs < GPMC_CS_NUM) {
+		u32 l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG1);
+
+		if ((l & GPMC_CONFIG1_DEVICETYPE(~0)) ==
+				GPMC_CONFIG1_DEVICETYPE_NAND) {
+			dev_info(gpmc->dev, "found NAND on CS: %d\n", cs);
+			nand->cs = cs;
+			gdp->cs_data->cs = cs;
+			return 0;
+		}
+		cs++;
+	}
+	return -ENODEV;
+}
+
 static __devinit void gpmc_update_nand_reg(struct gpmc *gpmc,
 				struct omap_nand_platform_data *nand)
 {
@@ -1450,8 +1474,14 @@ static __devinit int gpmc_probe(struct platform_device *pdev)
 
 	for (i = 0, gdq = gp->device_pdata, gd = gpmc->device;
 			(i < gp->num_device) && (*gdq); i++, gdq++) {
-		if ((*gdq)->is_nand)
+		if ((*gdq)->is_nand) {
+			ret = gpmc_acquire_nand_cs(gpmc, *gdq);
+			if (IS_ERR_VALUE(ret)) {
+				dev_err(gpmc->dev, "CS error: %d\n", ret);
+				continue;
+			}
 			gpmc_update_nand_reg(gpmc, (*gdq)->pdata);
+		}
 		ret = gpmc_setup_device(gpmc, gd, *gdq);
 		if (IS_ERR_VALUE(ret))
 			dev_err(gpmc->dev, "gpmc setup on %s failed\n",
-- 
1.7.10