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spi: spi-omap2-mcspi: Handle DMA size restriction on AM65x

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On AM654, McSPI can only support 4K - 1 bytes per transfer when DMA is
enabled. Therefore populate master->max_transfer_size callback to
inform client drivers of this restriction when DMA channels are
available.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200204124816.16735-2-vigneshr@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Vignesh Raghavendra 2020-02-04 18:18:15 +05:30 committed by Mark Brown
parent a5362b84bd
commit e4e8276a4f
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
2 changed files with 27 additions and 0 deletions
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26
drivers/spi/spi-omap2-mcspi.c
View file

@ -130,6 +130,7 @@ struct omap2_mcspi {
int fifo_depth;
bool slave_aborted;
unsigned int pin_dir:1;
size_t max_xfer_len;
};
struct omap2_mcspi_cs {
@ -1305,6 +1306,18 @@ static bool omap2_mcspi_can_dma(struct spi_master *master,
return (xfer->len >= DMA_MIN_BYTES);
}
static size_t omap2_mcspi_max_xfer_size(struct spi_device *spi)
{
struct omap2_mcspi *mcspi = spi_master_get_devdata(spi->master);
struct omap2_mcspi_dma *mcspi_dma =
&mcspi->dma_channels[spi->chip_select];
if (mcspi->max_xfer_len && mcspi_dma->dma_rx)
return mcspi->max_xfer_len;
return SIZE_MAX;
}
static int omap2_mcspi_controller_setup(struct omap2_mcspi *mcspi)
{
struct spi_master *master = mcspi->master;
@ -1373,6 +1386,11 @@ static struct omap2_mcspi_platform_config omap4_pdata = {
.regs_offset = OMAP4_MCSPI_REG_OFFSET,
};
static struct omap2_mcspi_platform_config am654_pdata = {
.regs_offset = OMAP4_MCSPI_REG_OFFSET,
.max_xfer_len = SZ_4K - 1,
};
static const struct of_device_id omap_mcspi_of_match[] = {
{
.compatible = "ti,omap2-mcspi",
@ -1382,6 +1400,10 @@ static const struct of_device_id omap_mcspi_of_match[] = {
.compatible = "ti,omap4-mcspi",
.data = &omap4_pdata,
},
{
.compatible = "ti,am654-mcspi",
.data = &am654_pdata,
},
{ },
};
MODULE_DEVICE_TABLE(of, omap_mcspi_of_match);
@ -1439,6 +1461,10 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
mcspi->pin_dir = pdata->pin_dir;
}
regs_offset = pdata->regs_offset;
if (pdata->max_xfer_len) {
mcspi->max_xfer_len = pdata->max_xfer_len;
master->max_transfer_size = omap2_mcspi_max_xfer_size;
}
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mcspi->base = devm_ioremap_resource(&pdev->dev, r);

1
include/linux/platform_data/spi-omap2-mcspi.h
View file

@ -11,6 +11,7 @@ struct omap2_mcspi_platform_config {
unsigned short num_cs;
unsigned int regs_offset;
unsigned int pin_dir:1;
size_t max_xfer_len;
};
struct omap2_mcspi_device_config {