mtd: mtk-quadspi: return amount of data transferred or error in read/write

Add checking of SPI transfer errors and return them from read/write
functions. Also return the amount of data transferred.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/drivers/mtd/spi-nor/mtk-quadspi.c b/drivers/mtd/spi-nor/mtk-quadspi.c
index ab92ac0f6b2b83ae3e84b63fe45f2b5f73ecdc51..e85687126c2526f29f2bcdf124b7fcd5cbc586a0 100644 (file)
--- a/drivers/mtd/spi-nor/mtk-quadspi.c
+++ b/drivers/mtd/spi-nor/mtk-quadspi.c
@@ -261,7 +261,7 @@ static ssize_t mt8173_nor_read(struct spi_nor *nor, loff_t from, size_t length,
                        return ret;
                buf[i] = readb(mt8173_nor->base + MTK_NOR_RDATA_REG);
        }
-       return 0;
+       return length;
 }
 
 static int mt8173_nor_write_single_byte(struct mt8173_nor *mt8173_nor,
@@ -302,6 +302,7 @@ static ssize_t mt8173_nor_write(struct spi_nor *nor, loff_t to, size_t len,
 {
        int ret;
        struct mt8173_nor *mt8173_nor = nor->priv;
+       size_t i;
 
        ret = mt8173_nor_write_buffer_enable(mt8173_nor);
        if (ret < 0) {
@@ -309,13 +310,12 @@ static ssize_t mt8173_nor_write(struct spi_nor *nor, loff_t to, size_t len,
                return ret;
        }
 
-       while (len >= SFLASH_WRBUF_SIZE) {
+       for (i = 0; i + SFLASH_WRBUF_SIZE <= len; i += SFLASH_WRBUF_SIZE) {
                ret = mt8173_nor_write_buffer(mt8173_nor, to, buf);
                if (ret < 0) {
                        dev_err(mt8173_nor->dev, "write buffer failed!\n");
                        return ret;
                }
-               len -= SFLASH_WRBUF_SIZE;
                to += SFLASH_WRBUF_SIZE;
                buf += SFLASH_WRBUF_SIZE;
                (*retlen) += SFLASH_WRBUF_SIZE;
@@ -326,9 +326,9 @@ static ssize_t mt8173_nor_write(struct spi_nor *nor, loff_t to, size_t len,
                return ret;
        }
 
-       if (len) {
-               ret = mt8173_nor_write_single_byte(mt8173_nor, to, (int)len,
-                                                  (u8 *)buf);
+       if (i < len) {
+               ret = mt8173_nor_write_single_byte(mt8173_nor, to,
+                                                  (int)(len - i), (u8 *)buf);
                if (ret < 0) {
                        dev_err(mt8173_nor->dev, "write single byte failed!\n");
                        return ret;
@@ -336,7 +336,7 @@ static ssize_t mt8173_nor_write(struct spi_nor *nor, loff_t to, size_t len,
                (*retlen) += len;
        }
 
-       return 0;
+       return len;
 }
 
 static int mt8173_nor_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)