path: root/Documentation/spi
diff options
authorEric Miao <eric.y.miao@gmail.com>2007-04-05 04:07:20 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2007-04-21 23:14:01 +0100
commit7053acbd78336abf5d4bc3d8a875a03624cfb83f (patch)
tree76dff22217a91d40c1d44292c0454d31cad55f15 /Documentation/spi
parenta79220b7633b3926a9bd3527bdac3f04dbe6845c (diff)
[ARM] 4304/1: removes the unnecessary bit number from CKENnn_XXXX
This patch removes the unnecessary bit number from CKENnn_XXXX definitions for PXA, so that CKEN0_PWM0 --> CKEN_PWM0 CKEN1_PWM1 --> CKEN_PWM1 ... CKEN24_CAMERA --> CKEN_CAMERA The reasons for the change of these defitions are: 1. they do not scale - they are currently valid for pxa2xx, but definitely not valid for pxa3xx, e.g., pxa3xx has bit 3 for camera instead of bit 24 2. they are unnecessary - the peripheral name within the definition has already announced its usage, we don't need those bit numbers to know which peripheral we are going to enable/disable clock for 3. they are inconvenient - think about this: a driver programmer for pxa has to remember which bit in the CKEN register to turn on/off Another change in the patch is to make the definitions equal to its clock bit index, so that #define CKEN_CAMERA (24) instead of #define CKEN_CAMERA (1 << 24) this change, however, will add a run-time bit shift operation in pxa_set_cken(), but the benefit of this change is that it scales when bit index exceeds 32, e.g., pxa3xx has two registers CKENA and CKENB, totally 64 bit for this, suppose CAMERA clock enabling bit is CKENB:10, one can simply define CKEN_CAMERA to be (32 + 10) and so that pxa_set_cken() need minimum change to adapt to that. Signed-off-by: eric miao <eric.y.miao@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'Documentation/spi')
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/spi/pxa2xx b/Documentation/spi/pxa2xx
index f9717fe9bd85..215e3b8e7266 100644
--- a/Documentation/spi/pxa2xx
+++ b/Documentation/spi/pxa2xx
@@ -62,7 +62,7 @@ static struct resource pxa_spi_nssp_resources[] = {
static struct pxa2xx_spi_master pxa_nssp_master_info = {
.ssp_type = PXA25x_NSSP, /* Type of SSP */
- .clock_enable = CKEN9_NSSP, /* NSSP Peripheral clock */
+ .clock_enable = CKEN_NSSP, /* NSSP Peripheral clock */
.num_chipselect = 1, /* Matches the number of chips attached to NSSP */
.enable_dma = 1, /* Enables NSSP DMA */