diff options
Diffstat (limited to 'drivers/spi/spi-bcm2835aux.c')
| -rw-r--r-- | drivers/spi/spi-bcm2835aux.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index c8acde017b6a..a105db371417 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -396,6 +396,38 @@ static void bcm2835aux_spi_handle_err(struct spi_master *master, bcm2835aux_spi_reset_hw(bs); } +static int bcm2835aux_spi_setup(struct spi_device *spi) +{ + int ret; + + /* sanity check for native cs */ + if (spi->mode & SPI_NO_CS) + return 0; + if (gpio_is_valid(spi->cs_gpio)) + return 0; + + /* for dt-backwards compatibility: only support native on CS0 + * known things not supported with broken native CS: + * * multiple chip-selects: cs0-cs2 are all + * simultaniously asserted whenever there is a transfer + * this even includes SPI_NO_CS + * * SPI_CS_HIGH: cs are always asserted low + * * cs_change: cs is deasserted after each spi_transfer + * * cs_delay_usec: cs is always deasserted one SCK cycle + * after the last transfer + * probably more... + */ + dev_warn(&spi->dev, + "Native CS is not supported - please configure cs-gpio in device-tree\n"); + + if (spi->chip_select == 0) + return 0; + + dev_warn(&spi->dev, "Native CS is not working for cs > 0\n"); + + return -EINVAL; +} + static int bcm2835aux_spi_probe(struct platform_device *pdev) { struct spi_master *master; @@ -425,6 +457,7 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) * a spi_transfer */ master->num_chipselect = 1; + master->setup = bcm2835aux_spi_setup; master->transfer_one = bcm2835aux_spi_transfer_one; master->handle_err = bcm2835aux_spi_handle_err; master->prepare_message = bcm2835aux_spi_prepare_message; |