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spi-imx: Implements handling of the SPI_READY mode flag. 

This patch implements consideration of the SPI_READY mode flag as
defined in spi.h. It extends the device tree bindings to support
the values defined by the reference manual for the DRCTL field.

Thus supporting edge-triggered and level-triggered bursts.

Signed-off-by: Leif Middelschulte <Leif.Middelschulte@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Leif Middelschulte 2017-04-23 21:19:58 +02:00 committed by Mark Brown
parent c1ae3cfa0e
commit f72efa7e69
2 changed files with 25 additions and 2 deletions
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7
Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt
View File

@ -23,6 +23,12 @@ See the clock consumer binding,
Obsolete properties:
- fsl,spi-num-chipselects : Contains the number of the chipselect
Optional properties:
- fsl,spi-rdy-drctl: Integer, representing the value of DRCTL, the register
controlling the SPI_READY handling. Note that to enable the DRCTL consideration,
the SPI_READY mode-flag needs to be set too.
Valid values are: 0 (disabled), 1 (edge-triggered burst) and 2 (level-triggered burst).
Example:
ecspi@70010000 {
@ -35,4 +41,5 @@ ecspi@70010000 {
<&gpio3 25 0>; /* GPIO3_25 */
dmas = <&sdma 3 7 1>, <&sdma 4 7 2>;
dma-names = "rx", "tx";
fsl,spi-rdy-drctl = <1>;
};

20
drivers/spi/spi-imx.c
View File

@ -95,6 +95,7 @@ struct spi_imx_data {
unsigned int spi_bus_clk;
unsigned int bytes_per_word;
unsigned int spi_drctl;
unsigned int count;
void (*tx)(struct spi_imx_data *);
@ -246,6 +247,7 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
#define MX51_ECSPI_CTRL_XCH (1 << 2)
#define MX51_ECSPI_CTRL_SMC (1 << 3)
#define MX51_ECSPI_CTRL_MODE_MASK (0xf << 4)
#define MX51_ECSPI_CTRL_DRCTL(drctl) ((drctl) << 16)
#define MX51_ECSPI_CTRL_POSTDIV_OFFSET 8
#define MX51_ECSPI_CTRL_PREDIV_OFFSET 12
#define MX51_ECSPI_CTRL_CS(cs) ((cs) << 18)
@ -355,6 +357,12 @@ static int mx51_ecspi_config(struct spi_device *spi,
*/
ctrl |= MX51_ECSPI_CTRL_MODE_MASK;
/*
* Enable SPI_RDY handling (falling edge/level triggered).
*/
if (spi->mode & SPI_READY)
ctrl |= MX51_ECSPI_CTRL_DRCTL(spi_imx->spi_drctl);
/* set clock speed */
ctrl |= mx51_ecspi_clkdiv(spi_imx, config->speed_hz, &clk);
spi_imx->spi_bus_clk = clk;
@ -1173,7 +1181,7 @@ static int spi_imx_probe(struct platform_device *pdev)
struct spi_master *master;
struct spi_imx_data *spi_imx;
struct resource *res;
int i, ret, irq;
int i, ret, irq, spi_drctl;
if (!np && !mxc_platform_info) {
dev_err(&pdev->dev, "can't get the platform data\n");
@ -1181,6 +1189,12 @@ static int spi_imx_probe(struct platform_device *pdev)
}
master = spi_alloc_master(&pdev->dev, sizeof(struct spi_imx_data));
ret = of_property_read_u32(np, "fsl,spi-rdy-drctl", &spi_drctl);
if ((ret < 0) || (spi_drctl >= 0x3)) {
/* '11' is reserved */
spi_drctl = 0;
}
if (!master)
return -ENOMEM;
@ -1216,7 +1230,9 @@ static int spi_imx_probe(struct platform_device *pdev)
spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
if (is_imx35_cspi(spi_imx) || is_imx51_ecspi(spi_imx))
spi_imx->bitbang.master->mode_bits |= SPI_LOOP;
spi_imx->bitbang.master->mode_bits |= SPI_LOOP | SPI_READY;
spi_imx->spi_drctl = spi_drctl;
init_completion(&spi_imx->xfer_done);