spi: davinci: add support for adding delay between word's transmissions
This patch adds ability to configure delay between transmission of
words over SPI bus if it's required by SPI slave devices.
New optional SPI slave property:
- ti,spi-word-delay : delay between transmission of words
(SPIFMTn.WDELAY, SPIDAT1.WDEL)
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 84a9fb1..25886d8 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -65,6 +65,7 @@
/* SPIDAT1 (upper 16 bit defines) */
#define SPIDAT1_CSHOLD_MASK BIT(12)
+#define SPIDAT1_WDEL BIT(10)
/* SPIGCR1 */
#define SPIGCR1_CLKMOD_MASK BIT(1)
@@ -209,6 +210,7 @@
{
struct davinci_spi *dspi;
struct davinci_spi_platform_data *pdata;
+ struct davinci_spi_config *spicfg = spi->controller_data;
u8 chip_sel = spi->chip_select;
u16 spidat1 = CS_DEFAULT;
bool gpio_chipsel = false;
@@ -223,6 +225,10 @@
gpio = spi->cs_gpio;
}
+ /* program delay transfers if tx_delay is non zero */
+ if (spicfg->wdelay)
+ spidat1 |= SPIDAT1_WDEL;
+
/*
* Board specific chip select logic decides the polarity and cs
* line for the controller
@@ -237,9 +243,9 @@
spidat1 |= SPIDAT1_CSHOLD_MASK;
spidat1 &= ~(0x1 << chip_sel);
}
-
- iowrite16(spidat1, dspi->base + SPIDAT1 + 2);
}
+
+ iowrite16(spidat1, dspi->base + SPIDAT1 + 2);
}
/**
@@ -285,7 +291,7 @@
int prescale;
dspi = spi_master_get_devdata(spi->master);
- spicfg = (struct davinci_spi_config *)spi->controller_data;
+ spicfg = spi->controller_data;
if (!spicfg)
spicfg = &davinci_spi_default_cfg;
@@ -333,6 +339,14 @@
spifmt |= SPIFMT_PHASE_MASK;
/*
+ * Assume wdelay is used only on SPI peripherals that has this field
+ * in SPIFMTn register and when it's configured from board file or DT.
+ */
+ if (spicfg->wdelay)
+ spifmt |= ((spicfg->wdelay << SPIFMT_WDELAY_SHIFT)
+ & SPIFMT_WDELAY_MASK);
+
+ /*
* Version 1 hardware supports two basic SPI modes:
* - Standard SPI mode uses 4 pins, with chipselect
* - 3 pin SPI is a 4 pin variant without CS (SPI_NO_CS)
@@ -349,9 +363,6 @@
u32 delay = 0;
- spifmt |= ((spicfg->wdelay << SPIFMT_WDELAY_SHIFT)
- & SPIFMT_WDELAY_MASK);
-
if (spicfg->odd_parity)
spifmt |= SPIFMT_ODD_PARITY_MASK;
@@ -383,6 +394,26 @@
return 0;
}
+static int davinci_spi_of_setup(struct spi_device *spi)
+{
+ struct davinci_spi_config *spicfg = spi->controller_data;
+ struct device_node *np = spi->dev.of_node;
+ u32 prop;
+
+ if (spicfg == NULL && np) {
+ spicfg = kzalloc(sizeof(*spicfg), GFP_KERNEL);
+ if (!spicfg)
+ return -ENOMEM;
+ *spicfg = davinci_spi_default_cfg;
+ /* override with dt configured values */
+ if (!of_property_read_u32(np, "ti,spi-wdelay", &prop))
+ spicfg->wdelay = (u8)prop;
+ spi->controller_data = spicfg;
+ }
+
+ return 0;
+}
+
/**
* davinci_spi_setup - This functions will set default transfer method
* @spi: spi device on which data transfer to be done
@@ -433,7 +464,16 @@
else
clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
- return retval;
+ return davinci_spi_of_setup(spi);
+}
+
+static void davinci_spi_cleanup(struct spi_device *spi)
+{
+ struct davinci_spi_config *spicfg = spi->controller_data;
+
+ spi->controller_data = NULL;
+ if (spi->dev.of_node)
+ kfree(spicfg);
}
static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status)
@@ -947,6 +987,7 @@
master->num_chipselect = pdata->num_chipselect;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16);
master->setup = davinci_spi_setup;
+ master->cleanup = davinci_spi_cleanup;
dspi->bitbang.chipselect = davinci_spi_chipselect;
dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;