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dw: spi: add support for Amazon's Alpine spi controller

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Add support for a new devicetree compatible string called
'amazon,alpine-apb-ssi', which is necessary for the Amazon Alpine spi
controller. 'amazon,alpine-dw-apb-ssi' is used in the dw spi driver if
specified in the devicetree.  Otherwise, fall back to driver default
behavior, i.e. original dw IP hw driver behavior.

Signed-off-by: Talel Shenhar <talel@amazon.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Talel Shenhar 2018-10-11 14:20:07 +03:00 committed by Mark Brown
parent d49a303667
commit f2d7047948
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
3 changed files with 17 additions and 0 deletions
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9
drivers/spi/spi-dw-mmio.c
View file

@ -126,6 +126,14 @@ static int dw_spi_mscc_jaguar2_init(struct platform_device *pdev,
JAGUAR2_IF_SI_OWNER_OFFSET);
}
static int dw_spi_alpine_init(struct platform_device *pdev,
struct dw_spi_mmio *dwsmmio)
{
dwsmmio->dws.cs_override = 1;
return 0;
}
static int dw_spi_mmio_probe(struct platform_device *pdev)
{
int (*init_func)(struct platform_device *pdev,
@ -230,6 +238,7 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
{ .compatible = "snps,dw-apb-ssi", },
{ .compatible = "mscc,ocelot-spi", .data = dw_spi_mscc_ocelot_init},
{ .compatible = "mscc,jaguar2-spi", .data = dw_spi_mscc_jaguar2_init},
{ .compatible = "amazon,alpine-dw-apb-ssi", .data = dw_spi_alpine_init},
{ /* end of table */}
};
MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);

6
drivers/spi/spi-dw.c
View file

@ -144,6 +144,8 @@ void dw_spi_set_cs(struct spi_device *spi, bool enable)
if (!enable)
dw_writel(dws, DW_SPI_SER, BIT(spi->chip_select));
else if (dws->cs_override)
dw_writel(dws, DW_SPI_SER, 0);
}
EXPORT_SYMBOL_GPL(dw_spi_set_cs);
@ -463,6 +465,10 @@ static void spi_hw_init(struct device *dev, struct dw_spi *dws)
dws->fifo_len = (fifo == 1) ? 0 : fifo;
dev_dbg(dev, "Detected FIFO size: %u bytes\n", dws->fifo_len);
}
/* enable HW fixup for explicit CS deselect for Amazon's alpine chip */
if (dws->cs_override)
dw_writel(dws, DW_SPI_CS_OVERRIDE, 0xF);
}
int dw_spi_add_host(struct device *dev, struct dw_spi *dws)

2
drivers/spi/spi-dw.h
View file

@ -32,6 +32,7 @@
#define DW_SPI_IDR 0x58
#define DW_SPI_VERSION 0x5c
#define DW_SPI_DR 0x60
#define DW_SPI_CS_OVERRIDE 0xf4
/* Bit fields in CTRLR0 */
#define SPI_DFS_OFFSET 0
@ -109,6 +110,7 @@ struct dw_spi {
u32 fifo_len; /* depth of the FIFO buffer */
u32 max_freq; /* max bus freq supported */
int cs_override;
u32 reg_io_width; /* DR I/O width in bytes */
u16 bus_num;
u16 num_cs; /* supported slave numbers */