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Commit c587b6fa authored by Feng Tang's avatar Feng Tang Committed by Grant Likely
Browse files

spi/dw_spi: add a FIFO depth detection 



FIFO depth is configurable for each implementation of DW core,
so add a depth detection for those interface drivers who don't set
the fifo_len explicitly

Signed-off-by: default avatarFeng Tang <feng.tang@intel.com>
Acked-by: default avatarJean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 99147b5c

drivers/spi/dw_spi.c

+16 −0
Original line number Diff line number Diff line
@@ -831,6 +831,22 @@ static void spi_hw_init(struct dw_spi *dws) 
	spi_mask_intr(dws, 0xff);

	spi_enable_chip(dws, 1);

	flush(dws);



	/*

	 * Try to detect the FIFO depth if not set by interface driver,

	 * the depth could be from 2 to 256 from HW spec

	 */

	if (!dws->fifo_len) {

		u32 fifo;

		for (fifo = 2; fifo <= 257; fifo++) {

			dw_writew(dws, txfltr, fifo);

			if (fifo != dw_readw(dws, txfltr))

				break;

		}



		dws->fifo_len = (fifo == 257) ? 0 : fifo;

		dw_writew(dws, txfltr, 0);

	}

}



int __devinit dw_spi_add_host(struct dw_spi *dws)