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spi: davinci: Choose correct pre-scaler limit based on SOC

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Currently the pre-scaler limit is incorrect. The value differs slightly
for various devices so a single value can't be used. Using the compatible
field select the correct pre-scaler limit.

Add new compatible field value for Keystone devices to support their
unique pre-scaler limit value.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Franklin S Cooper Jr 2015-07-22 07:32:22 -05:00 committed by Mark Brown
parent bba732d866
commit fa466c9197
3 changed files with 39 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/devicetree/bindings/spi/spi-davinci.txt
View File

@ -12,6 +12,8 @@ Required properties:
- compatible:
- "ti,dm6441-spi" for SPI used similar to that on DM644x SoC family
- "ti,da830-spi" for SPI used similar to that on DA8xx SoC family
- "ti,keystone-spi" for SPI used similar to that on Keystone2 SoC
family
- reg: Offset and length of SPI controller register space
- num-cs: Number of chip selects. This includes internal as well as
GPIO chip selects.

43
drivers/spi/spi-davinci.c
View File

@ -139,6 +139,8 @@ struct davinci_spi {
u32 (*get_tx)(struct davinci_spi *);
u8 *bytes_per_word;
u8 prescaler_limit;
};
static struct davinci_spi_config davinci_spi_default_cfg;
@ -266,7 +268,7 @@ static inline int davinci_spi_get_prescale(struct davinci_spi *dspi,
/* Subtract 1 to match what will be programmed into SPI register. */
ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz) - 1;
if (ret < 0 || ret > 255)
if (ret < dspi->prescaler_limit || ret > 255)
return -EINVAL;
return ret;
@ -833,13 +835,40 @@ rx_dma_failed:
}
#if defined(CONFIG_OF)
/* OF SPI data structure */
struct davinci_spi_of_data {
u8 version;
u8 prescaler_limit;
};
static const struct davinci_spi_of_data dm6441_spi_data = {
.version = SPI_VERSION_1,
.prescaler_limit = 2,
};
static const struct davinci_spi_of_data da830_spi_data = {
.version = SPI_VERSION_2,
.prescaler_limit = 2,
};
static const struct davinci_spi_of_data keystone_spi_data = {
.version = SPI_VERSION_1,
.prescaler_limit = 0,
};
static const struct of_device_id davinci_spi_of_match[] = {
{
.compatible = "ti,dm6441-spi",
.data = &dm6441_spi_data,
},
{
.compatible = "ti,da830-spi",
.data = (void *)SPI_VERSION_2,
.data = &da830_spi_data,
},
{
.compatible = "ti,keystone-spi",
.data = &keystone_spi_data,
},
{ },
};
@ -858,21 +887,21 @@ static int spi_davinci_get_pdata(struct platform_device *pdev,
struct davinci_spi *dspi)
{
struct device_node *node = pdev->dev.of_node;
struct davinci_spi_of_data *spi_data;
struct davinci_spi_platform_data *pdata;
unsigned int num_cs, intr_line = 0;
const struct of_device_id *match;
pdata = &dspi->pdata;
pdata->version = SPI_VERSION_1;
match = of_match_device(davinci_spi_of_match, &pdev->dev);
if (!match)
return -ENODEV;
/* match data has the SPI version number for SPI_VERSION_2 */
if (match->data == (void *)SPI_VERSION_2)
pdata->version = SPI_VERSION_2;
spi_data = (struct davinci_spi_of_data *)match->data;
pdata->version = spi_data->version;
pdata->prescaler_limit = spi_data->prescaler_limit;
/*
* default num_cs is 1 and all chipsel are internal to the chip
* indicated by chip_sel being NULL or cs_gpios being NULL or
@ -992,7 +1021,7 @@ static int davinci_spi_probe(struct platform_device *pdev)
dspi->bitbang.chipselect = davinci_spi_chipselect;
dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;
dspi->prescaler_limit = pdata->prescaler_limit;
dspi->version = pdata->version;
dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP;

1
include/linux/platform_data/spi-davinci.h
View File

@ -49,6 +49,7 @@ struct davinci_spi_platform_data {
u8 num_chipselect;
u8 intr_line;
u8 *chip_sel;
u8 prescaler_limit;
bool cshold_bug;
enum dma_event_q dma_event_q;
};