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Diffstat (limited to 'drivers/spi/spi.c')
-rw-r--r--drivers/spi/spi.c101
1 files changed, 79 insertions, 22 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 718cc1f49230..ab095acdb2a8 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -30,6 +30,7 @@
#include <linux/slab.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
+#include <linux/of_gpio.h>
#include <linux/pm_runtime.h>
#include <linux/export.h>
#include <linux/sched.h>
@@ -333,6 +334,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master)
spi->dev.parent = &master->dev;
spi->dev.bus = &spi_bus_type;
spi->dev.release = spidev_release;
+ spi->cs_gpio = -EINVAL;
device_initialize(&spi->dev);
return spi;
}
@@ -350,15 +352,16 @@ EXPORT_SYMBOL_GPL(spi_alloc_device);
int spi_add_device(struct spi_device *spi)
{
static DEFINE_MUTEX(spi_add_lock);
- struct device *dev = spi->master->dev.parent;
+ struct spi_master *master = spi->master;
+ struct device *dev = master->dev.parent;
struct device *d;
int status;
/* Chipselects are numbered 0..max; validate. */
- if (spi->chip_select >= spi->master->num_chipselect) {
+ if (spi->chip_select >= master->num_chipselect) {
dev_err(dev, "cs%d >= max %d\n",
spi->chip_select,
- spi->master->num_chipselect);
+ master->num_chipselect);
return -EINVAL;
}
@@ -382,6 +385,9 @@ int spi_add_device(struct spi_device *spi)
goto done;
}
+ if (master->cs_gpios)
+ spi->cs_gpio = master->cs_gpios[spi->chip_select];
+
/* Drivers may modify this initial i/o setup, but will
* normally rely on the device being setup. Devices
* using SPI_CS_HIGH can't coexist well otherwise...
@@ -492,8 +498,7 @@ static void spi_match_master_to_boardinfo(struct spi_master *master,
* The board info passed can safely be __initdata ... but be careful of
* any embedded pointers (platform_data, etc), they're copied as-is.
*/
-int __devinit
-spi_register_board_info(struct spi_board_info const *info, unsigned n)
+int spi_register_board_info(struct spi_board_info const *info, unsigned n)
{
struct boardinfo *bi;
int i;
@@ -806,7 +811,7 @@ err_init_queue:
/*-------------------------------------------------------------------------*/
-#if defined(CONFIG_OF) && !defined(CONFIG_SPARC)
+#if defined(CONFIG_OF)
/**
* of_register_spi_devices() - Register child devices onto the SPI bus
* @master: Pointer to spi_master device
@@ -861,6 +866,8 @@ static void of_register_spi_devices(struct spi_master *master)
spi->mode |= SPI_CPOL;
if (of_find_property(nc, "spi-cs-high", NULL))
spi->mode |= SPI_CS_HIGH;
+ if (of_find_property(nc, "spi-3wire", NULL))
+ spi->mode |= SPI_3WIRE;
/* Device speed */
prop = of_get_property(nc, "spi-max-frequency", &len);
@@ -1046,6 +1053,44 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
}
EXPORT_SYMBOL_GPL(spi_alloc_master);
+#ifdef CONFIG_OF
+static int of_spi_register_master(struct spi_master *master)
+{
+ u16 nb;
+ int i, *cs;
+ struct device_node *np = master->dev.of_node;
+
+ if (!np)
+ return 0;
+
+ nb = of_gpio_named_count(np, "cs-gpios");
+ master->num_chipselect = max(nb, master->num_chipselect);
+
+ if (nb < 1)
+ return 0;
+
+ cs = devm_kzalloc(&master->dev,
+ sizeof(int) * master->num_chipselect,
+ GFP_KERNEL);
+ master->cs_gpios = cs;
+
+ if (!master->cs_gpios)
+ return -ENOMEM;
+
+ memset(cs, -EINVAL, master->num_chipselect);
+
+ for (i = 0; i < nb; i++)
+ cs[i] = of_get_named_gpio(np, "cs-gpios", i);
+
+ return 0;
+}
+#else
+static int of_spi_register_master(struct spi_master *master)
+{
+ return 0;
+}
+#endif
+
/**
* spi_register_master - register SPI master controller
* @master: initialized master, originally from spi_alloc_master()
@@ -1077,6 +1122,10 @@ int spi_register_master(struct spi_master *master)
if (!dev)
return -ENODEV;
+ status = of_spi_register_master(master);
+ if (status)
+ return status;
+
/* even if it's just one always-selected device, there must
* be at least one chipselect
*/
@@ -1257,7 +1306,7 @@ EXPORT_SYMBOL_GPL(spi_busnum_to_master);
int spi_setup(struct spi_device *spi)
{
unsigned bad_bits;
- int status;
+ int status = 0;
/* help drivers fail *cleanly* when they need options
* that aren't supported with their current master
@@ -1272,7 +1321,8 @@ int spi_setup(struct spi_device *spi)
if (!spi->bits_per_word)
spi->bits_per_word = 8;
- status = spi->master->setup(spi);
+ if (spi->master->setup)
+ status = spi->master->setup(spi);
dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
"%u bits/w, %u Hz max --> %d\n",
@@ -1291,6 +1341,7 @@ EXPORT_SYMBOL_GPL(spi_setup);
static int __spi_async(struct spi_device *spi, struct spi_message *message)
{
struct spi_master *master = spi->master;
+ struct spi_transfer *xfer;
/* Half-duplex links include original MicroWire, and ones with
* only one data pin like SPI_3WIRE (switches direction) or where
@@ -1299,7 +1350,6 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
*/
if ((master->flags & SPI_MASTER_HALF_DUPLEX)
|| (spi->mode & SPI_3WIRE)) {
- struct spi_transfer *xfer;
unsigned flags = master->flags;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
@@ -1312,6 +1362,15 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
}
}
+ /**
+ * Set transfer bits_per_word as spi device default if it is not
+ * set for this transfer.
+ */
+ list_for_each_entry(xfer, &message->transfers, transfer_list) {
+ if (!xfer->bits_per_word)
+ xfer->bits_per_word = spi->bits_per_word;
+ }
+
message->spi = spi;
message->status = -EINPROGRESS;
return master->transfer(spi, message);
@@ -1588,12 +1647,18 @@ int spi_write_then_read(struct spi_device *spi,
struct spi_transfer x[2];
u8 *local_buf;
- /* Use preallocated DMA-safe buffer. We can't avoid copying here,
- * (as a pure convenience thing), but we can keep heap costs
- * out of the hot path ...
+ /* Use preallocated DMA-safe buffer if we can. We can't avoid
+ * copying here, (as a pure convenience thing), but we can
+ * keep heap costs out of the hot path unless someone else is
+ * using the pre-allocated buffer or the transfer is too large.
*/
- if ((n_tx + n_rx) > SPI_BUFSIZ)
- return -EINVAL;
+ if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
+ local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx), GFP_KERNEL);
+ if (!local_buf)
+ return -ENOMEM;
+ } else {
+ local_buf = buf;
+ }
spi_message_init(&message);
memset(x, 0, sizeof x);
@@ -1606,14 +1671,6 @@ int spi_write_then_read(struct spi_device *spi,
spi_message_add_tail(&x[1], &message);
}
- /* ... unless someone else is using the pre-allocated buffer */
- if (!mutex_trylock(&lock)) {
- local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
- if (!local_buf)
- return -ENOMEM;
- } else
- local_buf = buf;
-
memcpy(local_buf, txbuf, n_tx);
x[0].tx_buf = local_buf;
x[1].rx_buf = local_buf + n_tx;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 20:18:09 +0100