target/linux/generic/patches-3.3/048-spi-Dont-call-prepare-unprepare-transfer-if-not-popu.patch

   1 From 7dfd2bd70228d1f8d468d58cb3d12ecd618479ed Mon Sep 17 00:00:00 2001
   2 From: Shubhrajyoti D <shubhrajyoti@ti.com>
   3 Date: Thu, 10 May 2012 19:20:41 +0530
   4 Subject: [PATCH] spi: Dont call prepare/unprepare transfer if not populated
   5
   6 Currently the prepare/unprepare transfer are called unconditionally.
   7 The assumption is that every driver using the spi core queue infrastructure
   8 has to populate the prepare and unprepare functions. This encourages
   9 drivers to populate empty functions to prevent crashing.
  10 This patch prevents the call to prepare/unprepare if not populated.
  11
  12 Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
  13 Acked-by: Linus Walleij <linus.walleij@linaro.org>
  14 [grant.likely: fix whitespace defect]
  15 Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
  16 ---
  17  drivers/spi/spi.c |    4 ++--
  18  1 files changed, 2 insertions(+), 2 deletions(-)
  19
  20 --- a/drivers/spi/spi.c
  21 +++ b/drivers/spi/spi.c
  22 @@ -530,7 +530,7 @@ static void spi_pump_messages(struct kth
  23         /* Lock queue and check for queue work */
  24         spin_lock_irqsave(&master->queue_lock, flags);
  25         if (list_empty(&master->queue) || !master->running) {
  26 -               if (master->busy) {
  27 +               if (master->busy && master->unprepare_transfer_hardware) {
  28                         ret = master->unprepare_transfer_hardware(master);
  29                         if (ret) {
  30                                 dev_err(&master->dev,
  31 @@ -559,7 +559,7 @@ static void spi_pump_messages(struct kth
  32                 master->busy = true;
  33         spin_unlock_irqrestore(&master->queue_lock, flags);
  34
  35 -       if (!was_busy) {
  36 +       if (!was_busy && master->prepare_transfer_hardware) {
  37                 ret = master->prepare_transfer_hardware(master);
  38                 if (ret) {
  39                         dev_err(&master->dev,