mtd: spi-nor: Pointer parameter for FSR in spi_nor_read_fsr()

Let the callers pass the pointer to the DMA-able buffer where
the value of the Flag Status Register will be written. This way we
avoid the casts between int and u8, which can be confusing.

Caller stops compare the return value of spi_nor_read_fsr() with negative,
spi_nor_read_fsr() returns 0 on success and -errno otherwise.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

drivers/mtd/spi-nor/spi-nor.c

@@ -456,12 +456,15 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
 	return ret;
 }
 
-/*
- * Read the flag status register, returning its value in the location
- * Return the status register value.
- * Returns negative if error occurred.
+/**
+ * spi_nor_read_fsr() - Read the Flag Status Register.
+ * @nor:	pointer to 'struct spi_nor'
+ * @fsr:	pointer to a DMA-able buffer where the value of the
+ *              Flag Status Register will be written.
+ *
+ * Return: 0 on success, -errno otherwise.
  */
-static int spi_nor_read_fsr(struct spi_nor *nor)
+static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr)
 {
 	int ret;
 
@@ -470,20 +473,18 @@ static int spi_nor_read_fsr(struct spi_nor *nor)
 			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDFSR, 1),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_IN(1, nor->bouncebuf, 1));
+				   SPI_MEM_OP_DATA_IN(1, fsr, 1));
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
 		ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDFSR,
-						    nor->bouncebuf, 1);
+						    fsr, 1);
 	}
 
-	if (ret) {
+	if (ret)
 		pr_err("error %d reading FSR\n", ret);
-		return ret;
-	}
 
-	return nor->bouncebuf[0];
+	return ret;
 }
 
 /*
@@ -705,17 +706,18 @@ static int spi_nor_clear_fsr(struct spi_nor *nor)
 
 static int spi_nor_fsr_ready(struct spi_nor *nor)
 {
-	int fsr = spi_nor_read_fsr(nor);
-	if (fsr < 0)
-		return fsr;
+	int ret = spi_nor_read_fsr(nor, nor->bouncebuf);
+
+	if (ret)
+		return ret;
 
-	if (fsr & (FSR_E_ERR | FSR_P_ERR)) {
-		if (fsr & FSR_E_ERR)
+	if (nor->bouncebuf[0] & (FSR_E_ERR | FSR_P_ERR)) {
+		if (nor->bouncebuf[0] & FSR_E_ERR)
 			dev_err(nor->dev, "Erase operation failed.\n");
 		else
 			dev_err(nor->dev, "Program operation failed.\n");
 
-		if (fsr & FSR_PT_ERR)
+		if (nor->bouncebuf[0] & FSR_PT_ERR)
 			dev_err(nor->dev,
 			"Attempted to modify a protected sector.\n");
 
@@ -723,7 +725,7 @@ static int spi_nor_fsr_ready(struct spi_nor *nor)
 		return -EIO;
 	}
 
-	return fsr & FSR_READY;
+	return nor->bouncebuf[0] & FSR_READY;
 }
 
 static int spi_nor_ready(struct spi_nor *nor)