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path: root/drivers/spi/spi-bitbang.c
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Diffstat (limited to 'drivers/spi/spi-bitbang.c')
-rw-r--r--drivers/spi/spi-bitbang.c120
1 files changed, 63 insertions, 57 deletions
diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index a0e2204fc039..ebe18f0b5d23 100644
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
- * polling/bitbanging SPI master controller driver utilities
+ * Polling/bitbanging SPI host controller controller driver utilities
*/
#include <linux/spinlock.h>
@@ -11,6 +11,7 @@
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
+#include <linux/time64.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
@@ -37,104 +38,106 @@
* working quickly, or testing for differences that aren't speed related.
*/
+typedef unsigned int (*spi_bb_txrx_bufs_fn)(struct spi_device *, spi_bb_txrx_word_fn,
+ unsigned int, struct spi_transfer *,
+ unsigned int);
+
struct spi_bitbang_cs {
- unsigned nsecs; /* (clock cycle time)/2 */
- u32 (*txrx_word)(struct spi_device *spi, unsigned nsecs,
- u32 word, u8 bits, unsigned flags);
- unsigned (*txrx_bufs)(struct spi_device *,
- u32 (*txrx_word)(
- struct spi_device *spi,
- unsigned nsecs,
- u32 word, u8 bits,
- unsigned flags),
- unsigned, struct spi_transfer *,
- unsigned);
+ unsigned int nsecs; /* (clock cycle time) / 2 */
+ spi_bb_txrx_word_fn txrx_word;
+ spi_bb_txrx_bufs_fn txrx_bufs;
};
-static unsigned bitbang_txrx_8(
- struct spi_device *spi,
- u32 (*txrx_word)(struct spi_device *spi,
- unsigned nsecs,
- u32 word, u8 bits,
- unsigned flags),
- unsigned ns,
+static unsigned int bitbang_txrx_8(struct spi_device *spi,
+ spi_bb_txrx_word_fn txrx_word,
+ unsigned int ns,
struct spi_transfer *t,
- unsigned flags
-)
+ unsigned int flags)
{
- unsigned bits = t->bits_per_word;
- unsigned count = t->len;
+ struct spi_bitbang *bitbang;
+ unsigned int bits = t->bits_per_word;
+ unsigned int count = t->len;
const u8 *tx = t->tx_buf;
u8 *rx = t->rx_buf;
+ bitbang = spi_controller_get_devdata(spi->controller);
while (likely(count > 0)) {
u8 word = 0;
if (tx)
word = *tx++;
+ else
+ word = spi->mode & SPI_MOSI_IDLE_HIGH ? 0xFF : 0;
word = txrx_word(spi, ns, word, bits, flags);
if (rx)
*rx++ = word;
count -= 1;
}
+ if (bitbang->set_mosi_idle)
+ bitbang->set_mosi_idle(spi);
+
return t->len - count;
}
-static unsigned bitbang_txrx_16(
- struct spi_device *spi,
- u32 (*txrx_word)(struct spi_device *spi,
- unsigned nsecs,
- u32 word, u8 bits,
- unsigned flags),
- unsigned ns,
+static unsigned int bitbang_txrx_16(struct spi_device *spi,
+ spi_bb_txrx_word_fn txrx_word,
+ unsigned int ns,
struct spi_transfer *t,
- unsigned flags
-)
+ unsigned int flags)
{
- unsigned bits = t->bits_per_word;
- unsigned count = t->len;
+ struct spi_bitbang *bitbang;
+ unsigned int bits = t->bits_per_word;
+ unsigned int count = t->len;
const u16 *tx = t->tx_buf;
u16 *rx = t->rx_buf;
+ bitbang = spi_controller_get_devdata(spi->controller);
while (likely(count > 1)) {
u16 word = 0;
if (tx)
word = *tx++;
+ else
+ word = spi->mode & SPI_MOSI_IDLE_HIGH ? 0xFFFF : 0;
word = txrx_word(spi, ns, word, bits, flags);
if (rx)
*rx++ = word;
count -= 2;
}
+ if (bitbang->set_mosi_idle)
+ bitbang->set_mosi_idle(spi);
+
return t->len - count;
}
-static unsigned bitbang_txrx_32(
- struct spi_device *spi,
- u32 (*txrx_word)(struct spi_device *spi,
- unsigned nsecs,
- u32 word, u8 bits,
- unsigned flags),
- unsigned ns,
+static unsigned int bitbang_txrx_32(struct spi_device *spi,
+ spi_bb_txrx_word_fn txrx_word,
+ unsigned int ns,
struct spi_transfer *t,
- unsigned flags
-)
+ unsigned int flags)
{
- unsigned bits = t->bits_per_word;
- unsigned count = t->len;
+ struct spi_bitbang *bitbang;
+ unsigned int bits = t->bits_per_word;
+ unsigned int count = t->len;
const u32 *tx = t->tx_buf;
u32 *rx = t->rx_buf;
+ bitbang = spi_controller_get_devdata(spi->controller);
while (likely(count > 3)) {
u32 word = 0;
if (tx)
word = *tx++;
+ else
+ word = spi->mode & SPI_MOSI_IDLE_HIGH ? 0xFFFFFFFF : 0;
word = txrx_word(spi, ns, word, bits, flags);
if (rx)
*rx++ = word;
count -= 4;
}
+ if (bitbang->set_mosi_idle)
+ bitbang->set_mosi_idle(spi);
+
return t->len - count;
}
@@ -168,8 +171,8 @@ int spi_bitbang_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
if (!hz)
hz = spi->max_speed_hz;
if (hz) {
- cs->nsecs = (1000000000/2) / hz;
- if (cs->nsecs > (MAX_UDELAY_MS * 1000 * 1000))
+ cs->nsecs = (NSEC_PER_SEC / 2) / hz;
+ if (cs->nsecs > (MAX_UDELAY_MS * NSEC_PER_MSEC))
return -EINVAL;
}
@@ -210,6 +213,9 @@ int spi_bitbang_setup(struct spi_device *spi)
goto err_free;
}
+ if (bitbang->set_mosi_idle)
+ bitbang->set_mosi_idle(spi);
+
dev_dbg(&spi->dev, "%s, %u nsec/bit\n", __func__, 2 * cs->nsecs);
return 0;
@@ -233,7 +239,7 @@ EXPORT_SYMBOL_GPL(spi_bitbang_cleanup);
static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct spi_bitbang_cs *cs = spi->controller_state;
- unsigned nsecs = cs->nsecs;
+ unsigned int nsecs = cs->nsecs;
struct spi_bitbang *bitbang;
bitbang = spi_controller_get_devdata(spi->controller);
@@ -246,7 +252,7 @@ static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t)
}
if (spi->mode & SPI_3WIRE) {
- unsigned flags;
+ unsigned int flags;
flags = t->tx_buf ? SPI_CONTROLLER_NO_RX : SPI_CONTROLLER_NO_TX;
return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t, flags);
@@ -393,12 +399,12 @@ int spi_bitbang_init(struct spi_bitbang *bitbang)
EXPORT_SYMBOL_GPL(spi_bitbang_init);
/**
- * spi_bitbang_start - start up a polled/bitbanging SPI master driver
+ * spi_bitbang_start - start up a polled/bitbanging SPI host controller driver
* @bitbang: driver handle
*
* Caller should have zero-initialized all parts of the structure, and then
- * provided callbacks for chip selection and I/O loops. If the master has
- * a transfer method, its final step should call spi_bitbang_transfer; or,
+ * provided callbacks for chip selection and I/O loops. If the host controller has
+ * a transfer method, its final step should call spi_bitbang_transfer(); or,
* that's the default if the transfer routine is not initialized. It should
* also set up the bus number and number of chipselects.
*
@@ -406,9 +412,9 @@ EXPORT_SYMBOL_GPL(spi_bitbang_init);
* hardware that basically exposes a shift register) or per-spi_transfer
* (which takes better advantage of hardware like fifos or DMA engines).
*
- * Drivers using per-word I/O loops should use (or call) spi_bitbang_setup,
- * spi_bitbang_cleanup and spi_bitbang_setup_transfer to handle those spi
- * master methods. Those methods are the defaults if the bitbang->txrx_bufs
+ * Drivers using per-word I/O loops should use (or call) spi_bitbang_setup(),
+ * spi_bitbang_cleanup() and spi_bitbang_setup_transfer() to handle those SPI
+ * host controller methods. Those methods are the defaults if the bitbang->txrx_bufs
* routine isn't initialized.
*
* This routine registers the spi_controller, which will process requests in a
@@ -417,7 +423,7 @@ EXPORT_SYMBOL_GPL(spi_bitbang_init);
*
* On success, this routine will take a reference to the controller. The caller
* is responsible for calling spi_bitbang_stop() to decrement the reference and
- * spi_controller_put() as counterpart of spi_alloc_master() to prevent a memory
+ * spi_controller_put() as counterpart of spi_alloc_host() to prevent a memory
* leak.
*/
int spi_bitbang_start(struct spi_bitbang *bitbang)
@@ -450,4 +456,4 @@ void spi_bitbang_stop(struct spi_bitbang *bitbang)
EXPORT_SYMBOL_GPL(spi_bitbang_stop);
MODULE_LICENSE("GPL");
-
+MODULE_DESCRIPTION("Utilities for Bitbanging SPI host controllers");
generated by cgit (git 2.34.1) at 2025-07-13 16:32:48 +0000