The GPMC has wait-pin signals that can be assigned to a chip-select
to monitor the ready signal of an external device. Add a variable to
indicate the total number of wait-pins for a given device. This will
allow us to detect if the wait-pin being selected is valid or not.
When booting with device-tree read the number of wait-pins from the
device-tree blob. When device-tree is not used set the number of
wait-pins to 4 which is valid for OMAP2-5 devices. Newer devices
that have less wait-pins (such as AM335x) only support booting with
device-tree and so hard-coding the wait-pin number when not using
device-tree is fine.
Signed-off-by: Jon Hunter <jon-hunter@xxxxxx>
---
arch/arm/mach-omap2/gpmc.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 6ddecc8..452617b 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -108,6 +108,8 @@
#define GPMC_HAS_WR_ACCESS 0x1
#define GPMC_HAS_WR_DATA_MUX_BUS 0x2
+#define GPMC_NR_WAITPINS 4
+
/* XXX: Only NAND irq has been considered,currently these are the only ones used
*/
#define GPMC_NR_IRQ 2
@@ -153,6 +155,7 @@ static struct resource gpmc_cs_mem[GPMC_CS_NUM];
static DEFINE_SPINLOCK(gpmc_mem_lock);
/* Define chip-selects as reserved by default until probe completes */
static unsigned int gpmc_cs_map = ((1 << GPMC_CS_NUM) - 1);
+static unsigned int gpmc_nr_waitpins;
static struct device *gpmc_dev;
static int gpmc_irq;
static resource_size_t phys_base, mem_size;
@@ -1297,6 +1300,13 @@ static int gpmc_probe_dt(struct platform_device *pdev)
if (!of_id)
return 0;
+ ret = of_property_read_u32(pdev->dev.of_node, "gpmc,num-waitpins",
+ &gpmc_nr_waitpins);
+ if (ret) {
+ pr_err("%s: number of wait pins not found!\n", __func__);
+ return ret;
+ }
+
for_each_node_by_name(child, "nand") {
ret = gpmc_probe_nand_child(pdev, child);
if (ret < 0) {
@@ -1372,6 +1382,12 @@ static int gpmc_probe(struct platform_device *pdev)
if (IS_ERR_VALUE(gpmc_setup_irq()))
dev_warn(gpmc_dev, "gpmc_setup_irq failed\n");
+ /* Now the GPMC is initialised, unreserve the chip-selects */
+ gpmc_cs_map = 0;
+
+ if (!pdev->dev.of_node)
+ gpmc_nr_waitpins = GPMC_NR_WAITPINS;
+
rc = gpmc_probe_dt(pdev);
if (rc < 0) {
clk_disable_unprepare(gpmc_l3_clk);
--
1.7.10.4
--
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