spi: spi-mtk-nor: Unify write buffer on/off

The logical structures of mtk_nor_write_buffer_enable and
mtk_nor_write_buffer_disable are very similar, So it is necessary to
combine them into one.
Signed-off-by: bayi cheng <bayi.cheng@mediatek.com>
Link: https://lore.kernel.org/r/20221115124655.10124-1-bayi.cheng@mediatek.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-mtk-nor.c

@@ -444,36 +444,28 @@ static int mtk_nor_read_pio(struct mtk_nor *sp, const struct spi_mem_op *op)
 	return ret;
 }
 
-static int mtk_nor_write_buffer_enable(struct mtk_nor *sp)
+static int mtk_nor_setup_write_buffer(struct mtk_nor *sp, bool on)
 {
 	int ret;
 	u32 val;
 
-	if (sp->wbuf_en)
+	if (!(sp->wbuf_en ^ on))
 		return 0;
 
 	val = readl(sp->base + MTK_NOR_REG_CFG2);
-	writel(val | MTK_NOR_WR_BUF_EN, sp->base + MTK_NOR_REG_CFG2);
-	ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CFG2, val,
-				 val & MTK_NOR_WR_BUF_EN, 0, 10000);
-	if (!ret)
-		sp->wbuf_en = true;
-	return ret;
-}
-
-static int mtk_nor_write_buffer_disable(struct mtk_nor *sp)
-{
-	int ret;
-	u32 val;
+	if (on) {
+		writel(val | MTK_NOR_WR_BUF_EN, sp->base + MTK_NOR_REG_CFG2);
+		ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CFG2, val,
+					 val & MTK_NOR_WR_BUF_EN, 0, 10000);
+	} else {
+		writel(val & ~MTK_NOR_WR_BUF_EN, sp->base + MTK_NOR_REG_CFG2);
+		ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CFG2, val,
+					 !(val & MTK_NOR_WR_BUF_EN), 0, 10000);
+	}
 
-	if (!sp->wbuf_en)
-		return 0;
-	val = readl(sp->base + MTK_NOR_REG_CFG2);
-	writel(val & ~MTK_NOR_WR_BUF_EN, sp->base + MTK_NOR_REG_CFG2);
-	ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CFG2, val,
-				 !(val & MTK_NOR_WR_BUF_EN), 0, 10000);
 	if (!ret)
-		sp->wbuf_en = false;
+		sp->wbuf_en = on;
+
 	return ret;
 }
 
@@ -483,7 +475,7 @@ static int mtk_nor_pp_buffered(struct mtk_nor *sp, const struct spi_mem_op *op)
 	u32 val;
 	int ret, i;
 
-	ret = mtk_nor_write_buffer_enable(sp);
+	ret = mtk_nor_setup_write_buffer(sp, true);
 	if (ret < 0)
 		return ret;
 
@@ -502,7 +494,7 @@ static int mtk_nor_pp_unbuffered(struct mtk_nor *sp,
 	const u8 *buf = op->data.buf.out;
 	int ret;
 
-	ret = mtk_nor_write_buffer_disable(sp);
+	ret = mtk_nor_setup_write_buffer(sp, false);
 	if (ret < 0)
 		return ret;
 	writeb(buf[0], sp->base + MTK_NOR_REG_WDATA);
@@ -609,7 +601,7 @@ static int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 	}
 
 	if ((op->data.dir == SPI_MEM_DATA_IN) && mtk_nor_match_read(op)) {
-		ret = mtk_nor_write_buffer_disable(sp);
+		ret = mtk_nor_setup_write_buffer(sp, false);
 		if (ret < 0)
 			return ret;
 		mtk_nor_setup_bus(sp, op);