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path: root/drivers/spi/pxa2xx_spi.c
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Diffstat (limited to 'drivers/spi/pxa2xx_spi.c')
-rw-r--r--drivers/spi/pxa2xx_spi.c111
1 files changed, 90 insertions, 21 deletions
diff --git a/drivers/spi/pxa2xx_spi.c b/drivers/spi/pxa2xx_spi.c
index 33fcef3150d..885194a0741 100644
--- a/drivers/spi/pxa2xx_spi.c
+++ b/drivers/spi/pxa2xx_spi.c
@@ -28,6 +28,7 @@
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/clk.h>
+#include <linux/gpio.h>
#include <asm/io.h>
#include <asm/irq.h>
@@ -53,6 +54,7 @@ MODULE_ALIAS("platform:pxa2xx-spi");
#define RESET_DMA_CHANNEL (DCSR_NODESC | DMA_INT_MASK)
#define IS_DMA_ALIGNED(x) ((((u32)(x)) & 0x07) == 0)
#define MAX_DMA_LEN 8191
+#define DMA_ALIGNMENT 8
/*
* for testing SSCR1 changes that require SSP restart, basically
@@ -166,6 +168,8 @@ struct chip_data {
u8 enable_dma;
u8 bits_per_word;
u32 speed_hz;
+ int gpio_cs;
+ int gpio_cs_inverted;
int (*write)(struct driver_data *drv_data);
int (*read)(struct driver_data *drv_data);
void (*cs_control)(u32 command);
@@ -173,6 +177,32 @@ struct chip_data {
static void pump_messages(struct work_struct *work);
+static void cs_assert(struct driver_data *drv_data)
+{
+ struct chip_data *chip = drv_data->cur_chip;
+
+ if (chip->cs_control) {
+ chip->cs_control(PXA2XX_CS_ASSERT);
+ return;
+ }
+
+ if (gpio_is_valid(chip->gpio_cs))
+ gpio_set_value(chip->gpio_cs, chip->gpio_cs_inverted);
+}
+
+static void cs_deassert(struct driver_data *drv_data)
+{
+ struct chip_data *chip = drv_data->cur_chip;
+
+ if (chip->cs_control) {
+ chip->cs_control(PXA2XX_CS_DEASSERT);
+ return;
+ }
+
+ if (gpio_is_valid(chip->gpio_cs))
+ gpio_set_value(chip->gpio_cs, !chip->gpio_cs_inverted);
+}
+
static int flush(struct driver_data *drv_data)
{
unsigned long limit = loops_per_jiffy << 1;
@@ -183,16 +213,12 @@ static int flush(struct driver_data *drv_data)
while (read_SSSR(reg) & SSSR_RNE) {
read_SSDR(reg);
}
- } while ((read_SSSR(reg) & SSSR_BSY) && limit--);
+ } while ((read_SSSR(reg) & SSSR_BSY) && --limit);
write_SSSR(SSSR_ROR, reg);
return limit;
}
-static void null_cs_control(u32 command)
-{
-}
-
static int null_writer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
@@ -400,7 +426,6 @@ static void giveback(struct driver_data *drv_data)
msg = drv_data->cur_msg;
drv_data->cur_msg = NULL;
drv_data->cur_transfer = NULL;
- drv_data->cur_chip = NULL;
queue_work(drv_data->workqueue, &drv_data->pump_messages);
spin_unlock_irqrestore(&drv_data->lock, flags);
@@ -416,7 +441,7 @@ static void giveback(struct driver_data *drv_data)
* a message with an error, or next message is for another chip
*/
if (!last_transfer->cs_change)
- drv_data->cs_control(PXA2XX_CS_DEASSERT);
+ cs_deassert(drv_data);
else {
struct spi_message *next_msg;
@@ -445,19 +470,21 @@ static void giveback(struct driver_data *drv_data)
if (next_msg && next_msg->spi != msg->spi)
next_msg = NULL;
if (!next_msg || msg->state == ERROR_STATE)
- drv_data->cs_control(PXA2XX_CS_DEASSERT);
+ cs_deassert(drv_data);
}
msg->state = NULL;
if (msg->complete)
msg->complete(msg->context);
+
+ drv_data->cur_chip = NULL;
}
static int wait_ssp_rx_stall(void const __iomem *ioaddr)
{
unsigned long limit = loops_per_jiffy << 1;
- while ((read_SSSR(ioaddr) & SSSR_BSY) && limit--)
+ while ((read_SSSR(ioaddr) & SSSR_BSY) && --limit)
cpu_relax();
return limit;
@@ -467,7 +494,7 @@ static int wait_dma_channel_stop(int channel)
{
unsigned long limit = loops_per_jiffy << 1;
- while (!(DCSR(channel) & DCSR_STOPSTATE) && limit--)
+ while (!(DCSR(channel) & DCSR_STOPSTATE) && --limit)
cpu_relax();
return limit;
@@ -887,7 +914,7 @@ static void pump_transfers(unsigned long data)
/* Drop chip select only if cs_change is requested */
if (previous->cs_change)
- drv_data->cs_control(PXA2XX_CS_DEASSERT);
+ cs_deassert(drv_data);
}
/* Check for transfers that need multiple DMA segments */
@@ -922,7 +949,6 @@ static void pump_transfers(unsigned long data)
}
drv_data->n_bytes = chip->n_bytes;
drv_data->dma_width = chip->dma_width;
- drv_data->cs_control = chip->cs_control;
drv_data->tx = (void *)transfer->tx_buf;
drv_data->tx_end = drv_data->tx + transfer->len;
drv_data->rx = transfer->rx_buf;
@@ -1084,11 +1110,7 @@ static void pump_transfers(unsigned long data)
write_SSTO(chip->timeout, reg);
}
- /* FIXME, need to handle cs polarity,
- * this driver uses struct pxa2xx_spi_chip.cs_control to
- * specify a CS handling function, and it ignores most
- * struct spi_device.mode[s], including SPI_CS_HIGH */
- drv_data->cs_control(PXA2XX_CS_ASSERT);
+ cs_assert(drv_data);
/* after chip select, release the data by enabling service
* requests and interrupts, without changing any mode bits */
@@ -1166,6 +1188,44 @@ static int transfer(struct spi_device *spi, struct spi_message *msg)
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA)
+static int setup_cs(struct spi_device *spi, struct chip_data *chip,
+ struct pxa2xx_spi_chip *chip_info)
+{
+ int err = 0;
+
+ if (chip == NULL || chip_info == NULL)
+ return 0;
+
+ /* NOTE: setup() can be called multiple times, possibly with
+ * different chip_info, release previously requested GPIO
+ */
+ if (gpio_is_valid(chip->gpio_cs))
+ gpio_free(chip->gpio_cs);
+
+ /* If (*cs_control) is provided, ignore GPIO chip select */
+ if (chip_info->cs_control) {
+ chip->cs_control = chip_info->cs_control;
+ return 0;
+ }
+
+ if (gpio_is_valid(chip_info->gpio_cs)) {
+ err = gpio_request(chip_info->gpio_cs, "SPI_CS");
+ if (err) {
+ dev_err(&spi->dev, "failed to request chip select "
+ "GPIO%d\n", chip_info->gpio_cs);
+ return err;
+ }
+
+ chip->gpio_cs = chip_info->gpio_cs;
+ chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;
+
+ err = gpio_direction_output(chip->gpio_cs,
+ !chip->gpio_cs_inverted);
+ }
+
+ return err;
+}
+
static int setup(struct spi_device *spi)
{
struct pxa2xx_spi_chip *chip_info = NULL;
@@ -1211,7 +1271,7 @@ static int setup(struct spi_device *spi)
return -ENOMEM;
}
- chip->cs_control = null_cs_control;
+ chip->gpio_cs = -1;
chip->enable_dma = 0;
chip->timeout = TIMOUT_DFLT;
chip->dma_burst_size = drv_data->master_info->enable_dma ?
@@ -1225,8 +1285,6 @@ static int setup(struct spi_device *spi)
/* chip_info isn't always needed */
chip->cr1 = 0;
if (chip_info) {
- if (chip_info->cs_control)
- chip->cs_control = chip_info->cs_control;
if (chip_info->timeout)
chip->timeout = chip_info->timeout;
if (chip_info->tx_threshold)
@@ -1308,13 +1366,16 @@ static int setup(struct spi_device *spi)
spi_set_ctldata(spi, chip);
- return 0;
+ return setup_cs(spi, chip, chip_info);
}
static void cleanup(struct spi_device *spi)
{
struct chip_data *chip = spi_get_ctldata(spi);
+ if (gpio_is_valid(chip->gpio_cs))
+ gpio_free(chip->gpio_cs);
+
kfree(chip);
}
@@ -1438,6 +1499,7 @@ static int __init pxa2xx_spi_probe(struct platform_device *pdev)
master->bus_num = pdev->id;
master->num_chipselect = platform_info->num_chipselect;
+ master->dma_alignment = DMA_ALIGNMENT;
master->cleanup = cleanup;
master->setup = setup;
master->transfer = transfer;
@@ -1638,6 +1700,13 @@ static int pxa2xx_spi_resume(struct platform_device *pdev)
struct ssp_device *ssp = drv_data->ssp;
int status = 0;
+ if (drv_data->rx_channel != -1)
+ DRCMR(drv_data->ssp->drcmr_rx) =
+ DRCMR_MAPVLD | drv_data->rx_channel;
+ if (drv_data->tx_channel != -1)
+ DRCMR(drv_data->ssp->drcmr_tx) =
+ DRCMR_MAPVLD | drv_data->tx_channel;
+
/* Enable the SSP clock */
clk_enable(ssp->clk);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-11 16:29:20 +0000