[PATCH] spi: use linked lists rather than an array
This makes the SPI core and its users access transfers in the SPI message
structure as linked list not as an array, as discussed on LKML.
From: David Brownell <dbrownell@users.sourceforge.net>
Updates including doc, bugfixes to the list code, add
spi_message_add_tail(). Plus, initialize things _before_ grabbing the
locks in some cases (in case it grows more expensive). This also merges
some bitbang updates of mine that didn't yet make it into the mm tree.
Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: Dmitry Pervushin <dpervushin@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index c741776..dd8c6a9 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -155,10 +155,13 @@
struct ser_req *req = kzalloc(sizeof *req, SLAB_KERNEL);
int status;
int sample;
+ int i;
if (!req)
return -ENOMEM;
+ INIT_LIST_HEAD(&req->msg.transfers);
+
/* activate reference, so it has time to settle; */
req->xfer[0].tx_buf = &ref_on;
req->xfer[0].len = 1;
@@ -192,8 +195,8 @@
/* group all the transfers together, so we can't interfere with
* reading touchscreen state; disable penirq while sampling
*/
- req->msg.transfers = req->xfer;
- req->msg.n_transfer = 6;
+ for (i = 0; i < 6; i++)
+ spi_message_add_tail(&req->xfer[i], &req->msg);
disable_irq(spi->irq);
status = spi_sync(spi, &req->msg);
@@ -398,6 +401,7 @@
struct ads7846 *ts;
struct ads7846_platform_data *pdata = spi->dev.platform_data;
struct spi_transfer *x;
+ int i;
if (!spi->irq) {
dev_dbg(&spi->dev, "no IRQ?\n");
@@ -500,8 +504,8 @@
CS_CHANGE(x[-1]);
- ts->msg.transfers = ts->xfer;
- ts->msg.n_transfer = x - ts->xfer;
+ for (i = 0; i < x - ts->xfer; i++)
+ spi_message_add_tail(&ts->xfer[i], &ts->msg);
ts->msg.complete = ads7846_rx;
ts->msg.context = ts;