mtd: onenand: omap2: Configure driver from DT

Move away from platform data configuration and use pure DT approach.

Use generic probe function to deal with OneNAND node and remove now useless
gpmc_probe_onenand_child function. Import sync mode timing calculation
function from mach-omap2/gpmc-onenand.c

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
diff --git a/include/linux/omap-gpmc.h b/include/linux/omap-gpmc.h
index edfa280..053feb4 100644
--- a/include/linux/omap-gpmc.h
+++ b/include/linux/omap-gpmc.h
@@ -25,15 +25,43 @@
 
 struct gpmc_nand_regs;
 
+struct gpmc_onenand_info {
+	bool sync_read;
+	bool sync_write;
+	int burst_len;
+};
+
 #if IS_ENABLED(CONFIG_OMAP_GPMC)
 struct gpmc_nand_ops *gpmc_omap_get_nand_ops(struct gpmc_nand_regs *regs,
 					     int cs);
+/**
+ * gpmc_omap_onenand_set_timings - set optimized sync timings.
+ * @cs:      Chip Select Region
+ * @freq:    Chip frequency
+ * @latency: Burst latency cycle count
+ * @info:    Structure describing parameters used
+ *
+ * Sets optimized timings for the @cs region based on @freq and @latency.
+ * Updates the @info structure based on the GPMC settings.
+ */
+int gpmc_omap_onenand_set_timings(struct device *dev, int cs, int freq,
+				  int latency,
+				  struct gpmc_onenand_info *info);
+
 #else
 static inline struct gpmc_nand_ops *gpmc_omap_get_nand_ops(struct gpmc_nand_regs *regs,
 							   int cs)
 {
 	return NULL;
 }
+
+static inline
+int gpmc_omap_onenand_set_timings(struct device *dev, int cs, int freq,
+				  int latency,
+				  struct gpmc_onenand_info *info)
+{
+	return -EINVAL;
+}
 #endif /* CONFIG_OMAP_GPMC */
 
 extern int gpmc_calc_timings(struct gpmc_timings *gpmc_t,