[PATCH v3] spi-imx: Implements handling of the SPI_READY mode flag.

Leif Middelschulte
2017-04-23T19:19:58Z

From: Leif Middelschulte <leif.middelschulte-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

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-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
.../devicetree/bindings/spi/fsl-imx-cspi.txt | 7 +++++++
drivers/spi/spi-imx.c | 20 ++++++++++++++++++--
2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt b/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt
index 8bc95e2fc47f..31b5b21598ff 100644
--- a/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt
+++ b/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt
@@ -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>;
};
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 9a7c62f471dc..b402530a7a9a 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -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);

--
2.12.2

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