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path: root/drivers/spi/spi-davinci.c
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Diffstat (limited to 'drivers/spi/spi-davinci.c')
-rw-r--r--drivers/spi/spi-davinci.c50
1 files changed, 40 insertions, 10 deletions
diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 987afebea093..3cf9faa6cc3f 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -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;
@@ -255,7 +257,7 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value)
* This function calculates the prescale value that generates a clock rate
* less than or equal to the specified maximum.
*
- * Returns: calculated prescale - 1 for easy programming into SPI registers
+ * Returns: calculated prescale value for easy programming into SPI registers
* or negative error number if valid prescalar cannot be updated.
*/
static inline int davinci_spi_get_prescale(struct davinci_spi *dspi,
@@ -263,12 +265,13 @@ static inline int davinci_spi_get_prescale(struct davinci_spi *dspi,
{
int ret;
- ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz);
+ /* 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 < 1 || ret > 256)
+ if (ret < dspi->prescaler_limit || ret > 255)
return -EINVAL;
- return ret - 1;
+ return ret;
}
/**
@@ -832,13 +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,
},
{ },
};
@@ -857,21 +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
@@ -991,7 +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;