mtd: rawnand: sunxi: Remove support for GPIO-based Ready/Busy polling

None of the existing platforms connect the R/B pin to a GPIO (they all
use one of the dedicated R/B pin).
Anyway, if we ever get short of native R/B pins, it's probably better
to fallback to STATUS reg polling than trying to poll a GPIO.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/mtd/sunxi-nand.txt

@@ -22,8 +22,6 @@ Optional properties:
 - reset : phandle + reset specifier pair
 - reset-names : must contain "ahb"
 - allwinner,rb : shall contain the native Ready/Busy ids.
- or
-- rb-gpios : shall contain the gpios used as R/B pins.
 - nand-ecc-mode : one of the supported ECC modes ("hw", "soft", "soft_bch" or
 		  "none")
 

drivers/mtd/nand/raw/sunxi_nand.c

@@ -165,49 +165,16 @@
 
 #define NFC_MAX_CS		7
 
-/*
- * Ready/Busy detection type: describes the Ready/Busy detection modes
- *
- * @RB_NONE:	no external detection available, rely on STATUS command
- *		and software timeouts
- * @RB_NATIVE:	use sunxi NAND controller Ready/Busy support. The Ready/Busy
- *		pin of the NAND flash chip must be connected to one of the
- *		native NAND R/B pins (those which can be muxed to the NAND
- *		Controller)
- * @RB_GPIO:	use a simple GPIO to handle Ready/Busy status. The Ready/Busy
- *		pin of the NAND flash chip must be connected to a GPIO capable
- *		pin.
- */
-enum sunxi_nand_rb_type {
-	RB_NONE,
-	RB_NATIVE,
-	RB_GPIO,
-};
-
-/*
- * Ready/Busy structure: stores information related to Ready/Busy detection
- *
- * @type:	the Ready/Busy detection mode
- * @info:	information related to the R/B detection mode. Either a gpio
- *		id or a native R/B id (those supported by the NAND controller).
- */
-struct sunxi_nand_rb {
-	enum sunxi_nand_rb_type type;
-	union {
-		int gpio;
-		int nativeid;
-	} info;
-};
-
 /*
  * Chip Select structure: stores information related to NAND Chip Select
  *
  * @cs:		the NAND CS id used to communicate with a NAND Chip
- * @rb:		the Ready/Busy description
+ * @rb:		the Ready/Busy pin ID. -1 means no R/B pin connected to the
+ *		NFC
  */
 struct sunxi_nand_chip_sel {
 	u8 cs;
-	struct sunxi_nand_rb rb;
+	s8 rb;
 };
 
 /*
@@ -440,30 +407,19 @@ static int sunxi_nfc_dev_ready(struct mtd_info *mtd)
 	struct nand_chip *nand = mtd_to_nand(mtd);
 	struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(nand);
 	struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
-	struct sunxi_nand_rb *rb;
-	int ret;
+	u32 mask;
 
 	if (sunxi_nand->selected < 0)
 		return 0;
 
-	rb = &sunxi_nand->sels[sunxi_nand->selected].rb;
-
-	switch (rb->type) {
-	case RB_NATIVE:
-		ret = !!(readl(nfc->regs + NFC_REG_ST) &
-			 NFC_RB_STATE(rb->info.nativeid));
-		break;
-	case RB_GPIO:
-		ret = gpio_get_value(rb->info.gpio);
-		break;
-	case RB_NONE:
-	default:
-		ret = 0;
+	if (sunxi_nand->sels[sunxi_nand->selected].rb < 0) {
 		dev_err(nfc->dev, "cannot check R/B NAND status!\n");
-		break;
+		return 0;
 	}
 
-	return ret;
+	mask = NFC_RB_STATE(sunxi_nand->sels[sunxi_nand->selected].rb);
+
+	return !!(readl(nfc->regs + NFC_REG_ST) & mask);
 }
 
 static void sunxi_nfc_select_chip(struct mtd_info *mtd, int chip)
@@ -488,12 +444,11 @@ static void sunxi_nfc_select_chip(struct mtd_info *mtd, int chip)
 
 		ctl |= NFC_CE_SEL(sel->cs) | NFC_EN |
 		       NFC_PAGE_SHIFT(nand->page_shift);
-		if (sel->rb.type == RB_NONE) {
+		if (sel->rb < 0) {
 			nand->dev_ready = NULL;
 		} else {
 			nand->dev_ready = sunxi_nfc_dev_ready;
-			if (sel->rb.type == RB_NATIVE)
-				ctl |= NFC_RB_SEL(sel->rb.info.nativeid);
+			ctl |= NFC_RB_SEL(sel->rb);
 		}
 
 		writel(mtd->writesize, nfc->regs + NFC_REG_SPARE_AREA);
@@ -1946,26 +1901,10 @@ static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc,
 		chip->sels[i].cs = tmp;
 
 		if (!of_property_read_u32_index(np, "allwinner,rb", i, &tmp) &&
-		    tmp < 2) {
-			chip->sels[i].rb.type = RB_NATIVE;
-			chip->sels[i].rb.info.nativeid = tmp;
-		} else {
-			ret = of_get_named_gpio(np, "rb-gpios", i);
-			if (ret >= 0) {
-				tmp = ret;
-				chip->sels[i].rb.type = RB_GPIO;
-				chip->sels[i].rb.info.gpio = tmp;
-				ret = devm_gpio_request(dev, tmp, "nand-rb");
-				if (ret)
-					return ret;
-
-				ret = gpio_direction_input(tmp);
-				if (ret)
-					return ret;
-			} else {
-				chip->sels[i].rb.type = RB_NONE;
-			}
-		}
+		    tmp < 2)
+			chip->sels[i].rb = tmp;
+		else
+			chip->sels[i].rb = -1;
 	}
 
 	nand = &chip->nand;