@@ -240,6 +240,12 @@ typedef int (*spi_flash_read_fn)(struct spi_flash *, u32, size_t, void *);
int spi_flash_read_alg(struct spi_flash *flash, u32 offset, size_t len,
void *data, spi_flash_read_fn read_fn);
+/*
+ * Helper function to compute the number of dummy bytes from both the number
+ * of dummy cycles and the SPI protocol used for (Fast) Read operations.
+ */
+int spi_flash_set_dummy_byte(struct spi_flash *flash, u8 num_dummy_cycles);
+
#ifdef CONFIG_SPI_FLASH_MTD
int spi_flash_mtd_register(struct spi_flash *flash);
void spi_flash_mtd_unregister(void);
@@ -882,6 +882,17 @@ int stm_unlock(struct spi_flash *flash, u32 ofs, size_t len)
}
#endif
+int spi_flash_set_dummy_byte(struct spi_flash *flash, u8 num_dummy_cycles)
+{
+ u8 dummy_bits = num_dummy_cycles;
+
+ dummy_bits *= SPI_FLASH_PROTO_ADR_FROM_PROTO(flash->read_proto);
+ if (dummy_bits & 0x7)
+ return -EINVAL;
+
+ flash->dummy_byte = dummy_bits >> 3;
+ return 0;
+}
#ifdef CONFIG_SPI_FLASH_MACRONIX
static int macronix_quad_enable(struct spi_flash *flash)
This patch adds a helper function to ease the conversion between a number of dummy clock cycles and number of bytes. Actually this number of bytes depends on both the number of dummy clock cycles and SPI protocol used by (Fast) Read commands. This new function is exported so it can be used by other drivers. Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com> --- drivers/mtd/spi/sf_internal.h | 6 ++++++ drivers/mtd/spi/spi_flash.c | 11 +++++++++++ 2 files changed, 17 insertions(+)