[PATCH v5 05/11] spi: imx: Add support for loopback for ECSPI controllers

From: Anton Bondarenko
Date: Sat Dec 05 2015 - 11:59:11 EST


Support for ECSPI loopback for IMX51, IMX53 and IMX6Q using TEST register.

Signed-off-by: Mohsin Kazmi <mohsin_kazmi@xxxxxxxxxx>
Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@xxxxxxxxx>
---
drivers/spi/spi-imx.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 363276d..3525616 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -246,6 +246,9 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
#define MX51_ECSPI_STAT 0x18
#define MX51_ECSPI_STAT_RR (1 << 3)

+#define MX51_ECSPI_TEST 0x20
+#define MX51_ECSPI_LOOP BIT(31)
+
/* MX51 eCSPI */
static unsigned int mx51_ecspi_clkdiv(unsigned int fin, unsigned int fspi,
unsigned int *fres)
@@ -316,6 +319,7 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
u32 ctrl = MX51_ECSPI_CTRL_ENABLE, cfg = 0, dma = 0;
u32 tx_wml_cfg, rx_wml_cfg, rxt_wml_cfg;
u32 clk = config->speed_hz, delay;
+ u32 lpb = 0;

/*
* The hardware seems to have a race condition when changing modes. The
@@ -356,6 +360,12 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);

+ if (config->mode & SPI_LOOP)
+ lpb |= MX51_ECSPI_LOOP;
+
+ if ((readl(spi_imx->base + MX51_ECSPI_TEST) & MX51_ECSPI_LOOP) != lpb)
+ writel(lpb, spi_imx->base + MX51_ECSPI_TEST);
+
/*
* Wait until the changes in the configuration register CONFIGREG
* propagate into the hardware. It takes exactly one tick of the
@@ -1128,6 +1138,9 @@ static int spi_imx_probe(struct platform_device *pdev)
spi_imx = spi_master_get_devdata(master);
spi_imx->bitbang.master = master;

+ spi_imx->devtype_data = of_id ? of_id->data :
+ (struct spi_imx_devtype_data *)pdev->id_entry->driver_data;
+
for (i = 0; i < master->num_chipselect; i++) {
int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
if (!gpio_is_valid(cs_gpio) && mxc_platform_info)
@@ -1154,10 +1167,10 @@ 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;

- init_completion(&spi_imx->xfer_done);
+ if (is_imx51_ecspi(spi_imx))
+ spi_imx->bitbang.master->mode_bits |= SPI_LOOP;

- spi_imx->devtype_data = of_id ? of_id->data :
- (struct spi_imx_devtype_data *) pdev->id_entry->driver_data;
+ init_completion(&spi_imx->xfer_done);

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
spi_imx->base = devm_ioremap_resource(&pdev->dev, res);
--
2.6.3

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