aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi-atmel.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/spi/spi-atmel.c')
-rw-r--r--drivers/spi/spi-atmel.c102
1 files changed, 32 insertions, 70 deletions
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 74fddcd3282b..4954f0ab1606 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -23,8 +23,7 @@
#include <linux/of.h>
#include <linux/io.h>
-#include <linux/gpio.h>
-#include <linux/of_gpio.h>
+#include <linux/gpio/consumer.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pm_runtime.h>
@@ -312,7 +311,7 @@ struct atmel_spi {
/* Controller-specific per-slave state */
struct atmel_spi_device {
- unsigned int npcs_pin;
+ struct gpio_desc *npcs_pin;
u32 csr;
};
@@ -355,7 +354,6 @@ static bool atmel_spi_is_v2(struct atmel_spi *as)
static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
{
struct atmel_spi_device *asd = spi->controller_state;
- unsigned active = spi->mode & SPI_CS_HIGH;
u32 mr;
if (atmel_spi_is_v2(as)) {
@@ -379,7 +377,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
mr = spi_readl(as, MR);
if (as->use_cs_gpios)
- gpio_set_value(asd->npcs_pin, active);
+ gpiod_set_value(asd->npcs_pin, 1);
} else {
u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
int i;
@@ -396,19 +394,16 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
mr = spi_readl(as, MR);
mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
if (as->use_cs_gpios && spi->chip_select != 0)
- gpio_set_value(asd->npcs_pin, active);
+ gpiod_set_value(asd->npcs_pin, 1);
spi_writel(as, MR, mr);
}
- dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
- asd->npcs_pin, active ? " (high)" : "",
- mr);
+ dev_dbg(&spi->dev, "activate NPCS, mr %08x\n", mr);
}
static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
{
struct atmel_spi_device *asd = spi->controller_state;
- unsigned active = spi->mode & SPI_CS_HIGH;
u32 mr;
/* only deactivate *this* device; sometimes transfers to
@@ -420,14 +415,12 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
spi_writel(as, MR, mr);
}
- dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
- asd->npcs_pin, active ? " (low)" : "",
- mr);
+ dev_dbg(&spi->dev, "DEactivate NPCS, mr %08x\n", mr);
if (!as->use_cs_gpios)
spi_writel(as, CR, SPI_BIT(LASTXFER));
else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
- gpio_set_value(asd->npcs_pin, !active);
+ gpiod_set_value(asd->npcs_pin, 0);
}
static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
@@ -1188,7 +1181,6 @@ static int atmel_spi_setup(struct spi_device *spi)
struct atmel_spi_device *asd;
u32 csr;
unsigned int bits = spi->bits_per_word;
- unsigned int npcs_pin;
as = spi_master_get_devdata(spi->master);
@@ -1209,21 +1201,14 @@ static int atmel_spi_setup(struct spi_device *spi)
csr |= SPI_BIT(CSAAT);
/* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
- *
- * DLYBCT would add delays between words, slowing down transfers.
- * It could potentially be useful to cope with DMA bottlenecks, but
- * in those cases it's probably best to just use a lower bitrate.
*/
csr |= SPI_BF(DLYBS, 0);
- csr |= SPI_BF(DLYBCT, 0);
-
- /* chipselect must have been muxed as GPIO (e.g. in board setup) */
- npcs_pin = (unsigned long)spi->controller_data;
- if (!as->use_cs_gpios)
- npcs_pin = spi->chip_select;
- else if (gpio_is_valid(spi->cs_gpio))
- npcs_pin = spi->cs_gpio;
+ /* DLYBCT adds delays between words. This is useful for slow devices
+ * that need a bit of time to setup the next transfer.
+ */
+ csr |= SPI_BF(DLYBCT,
+ (as->spi_clk / 1000000 * spi->word_delay_usecs) >> 5);
asd = spi->controller_state;
if (!asd) {
@@ -1231,11 +1216,21 @@ static int atmel_spi_setup(struct spi_device *spi)
if (!asd)
return -ENOMEM;
- if (as->use_cs_gpios)
- gpio_direction_output(npcs_pin,
- !(spi->mode & SPI_CS_HIGH));
+ /*
+ * If use_cs_gpios is true this means that we have "cs-gpios"
+ * defined in the device tree node so we should have
+ * gotten the GPIO lines from the device tree inside the
+ * SPI core. Warn if this is not the case but continue since
+ * CS GPIOs are after all optional.
+ */
+ if (as->use_cs_gpios) {
+ if (!spi->cs_gpiod) {
+ dev_err(&spi->dev,
+ "host claims to use CS GPIOs but no CS found in DT by the SPI core\n");
+ }
+ asd->npcs_pin = spi->cs_gpiod;
+ }
- asd->npcs_pin = npcs_pin;
spi->controller_state = asd;
}
@@ -1473,41 +1468,6 @@ static void atmel_get_caps(struct atmel_spi *as)
as->caps.has_pdc_support = version < 0x212;
}
-/*-------------------------------------------------------------------------*/
-static int atmel_spi_gpio_cs(struct platform_device *pdev)
-{
- struct spi_master *master = platform_get_drvdata(pdev);
- struct atmel_spi *as = spi_master_get_devdata(master);
- struct device_node *np = master->dev.of_node;
- int i;
- int ret = 0;
- int nb = 0;
-
- if (!as->use_cs_gpios)
- return 0;
-
- if (!np)
- return 0;
-
- nb = of_gpio_named_count(np, "cs-gpios");
- for (i = 0; i < nb; i++) {
- int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
- "cs-gpios", i);
-
- if (cs_gpio == -EPROBE_DEFER)
- return cs_gpio;
-
- if (gpio_is_valid(cs_gpio)) {
- ret = devm_gpio_request(&pdev->dev, cs_gpio,
- dev_name(&pdev->dev));
- if (ret)
- return ret;
- }
- }
-
- return 0;
-}
-
static void atmel_spi_init(struct atmel_spi *as)
{
spi_writel(as, CR, SPI_BIT(SWRST));
@@ -1560,6 +1520,7 @@ static int atmel_spi_probe(struct platform_device *pdev)
goto out_free;
/* the spi->mode bits understood by this driver: */
+ master->use_gpio_descriptors = true;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
master->dev.of_node = pdev->dev.of_node;
@@ -1592,6 +1553,11 @@ static int atmel_spi_probe(struct platform_device *pdev)
atmel_get_caps(as);
+ /*
+ * If there are chip selects in the device tree, those will be
+ * discovered by the SPI core when registering the SPI master
+ * and assigned to each SPI device.
+ */
as->use_cs_gpios = true;
if (atmel_spi_is_v2(as) &&
pdev->dev.of_node &&
@@ -1600,10 +1566,6 @@ static int atmel_spi_probe(struct platform_device *pdev)
master->num_chipselect = 4;
}
- ret = atmel_spi_gpio_cs(pdev);
- if (ret)
- goto out_unmap_regs;
-
as->use_dma = false;
as->use_pdc = false;
if (as->caps.has_dma_support) {