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Commit 278ac33b authored by Mark Brown's avatar Mark Brown
Browse files

Merge remote-tracking branch 'spi/topic/quad' into spi-next

parents 85cac431 a110f93d

Documentation/devicetree/bindings/spi/spi-bus.txt

+10 −0
Original line number Diff line number Diff line
@@ -55,6 +55,16 @@ contain the following properties. 
    		chip select active high

- spi-3wire       - (optional) Empty property indicating device requires

    		    3-wire mode.

- spi-tx-bus-width - (optional) The bus width(number of data wires) that

                      used for MOSI. Defaults to 1 if not present.

- spi-rx-bus-width - (optional) The bus width(number of data wires) that

                      used for MISO. Defaults to 1 if not present.



Some SPI controllers and devices support Dual and Quad SPI transfer mode.

It allows data in SPI system transfered in 2 wires(DUAL) or 4 wires(QUAD).

Now the value that spi-tx-bus-width and spi-rx-bus-width can receive is

only 1(SINGLE), 2(DUAL) and 4(QUAD).

Dual/Quad mode is not allowed when 3-wire mode is used.



If a gpio chipselect is used for the SPI slave the gpio number will be passed

via the cs_gpio

drivers/spi/spi.c

+37 −40
Original line number Diff line number Diff line
@@ -886,13 +886,8 @@ static void of_register_spi_devices(struct spi_master *master) 
			spi->mode |= SPI_3WIRE;



		/* Device DUAL/QUAD mode */

		prop = of_get_property(nc, "spi-tx-nbits", &len);

		if (!prop || len < sizeof(*prop)) {

			dev_err(&master->dev, "%s has no 'spi-tx-nbits' property\n",

				nc->full_name);

			spi_dev_put(spi);

			continue;

		}

		prop = of_get_property(nc, "spi-tx-bus-width", &len);

		if (prop && len == sizeof(*prop)) {

			switch (be32_to_cpup(prop)) {

			case SPI_NBITS_SINGLE:

				break;
@@ -903,18 +898,16 @@ static void of_register_spi_devices(struct spi_master *master) 
				spi->mode |= SPI_TX_QUAD;

				break;

			default:

			dev_err(&master->dev, "spi-tx-nbits value is not supported\n");

				dev_err(&master->dev,

					"spi-tx-bus-width %d not supported\n",

					be32_to_cpup(prop));

				spi_dev_put(spi);

				continue;

			}



		prop = of_get_property(nc, "spi-rx-nbits", &len);

		if (!prop || len < sizeof(*prop)) {

			dev_err(&master->dev, "%s has no 'spi-rx-nbits' property\n",

				nc->full_name);

			spi_dev_put(spi);

			continue;

		}



		prop = of_get_property(nc, "spi-rx-bus-width", &len);

		if (prop && len == sizeof(*prop)) {

			switch (be32_to_cpup(prop)) {

			case SPI_NBITS_SINGLE:

				break;
@@ -925,10 +918,13 @@ static void of_register_spi_devices(struct spi_master *master) 
				spi->mode |= SPI_RX_QUAD;

				break;

			default:

			dev_err(&master->dev, "spi-rx-nbits value is not supported\n");

				dev_err(&master->dev,

					"spi-rx-bus-width %d not supported\n",

					be32_to_cpup(prop));

				spi_dev_put(spi);

				continue;

			}

		}



		/* Device speed */

		prop = of_get_property(nc, "spi-max-frequency", &len);
@@ -1480,6 +1476,7 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message) 
			return -EINVAL;

		if (xfer->speed_hz && master->max_speed_hz &&

		    xfer->speed_hz > master->max_speed_hz)

			return -EINVAL;



		if (xfer->tx_buf && !xfer->tx_nbits)

			xfer->tx_nbits = SPI_NBITS_SINGLE;