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Diffstat (limited to 'arch/arm/plat-omap/mcbsp.c')
-rw-r--r--arch/arm/plat-omap/mcbsp.c50
1 files changed, 32 insertions, 18 deletions
diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index efa0e0111f3..a3d2313460b 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -328,14 +328,15 @@ void omap_mcbsp_free(unsigned int id)
EXPORT_SYMBOL(omap_mcbsp_free);
/*
- * Here we start the McBSP, by enabling the sample
- * generator, both transmitter and receivers,
- * and the frame sync.
+ * Here we start the McBSP, by enabling transmitter, receiver or both.
+ * If no transmitter or receiver is active prior calling, then sample-rate
+ * generator and frame sync are started.
*/
-void omap_mcbsp_start(unsigned int id)
+void omap_mcbsp_start(unsigned int id, int tx, int rx)
{
struct omap_mcbsp *mcbsp;
void __iomem *io_base;
+ int idle;
u16 w;
if (!omap_mcbsp_check_valid_id(id)) {
@@ -348,32 +349,40 @@ void omap_mcbsp_start(unsigned int id)
mcbsp->rx_word_length = (OMAP_MCBSP_READ(io_base, RCR1) >> 5) & 0x7;
mcbsp->tx_word_length = (OMAP_MCBSP_READ(io_base, XCR1) >> 5) & 0x7;
- /* Start the sample generator */
- w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w | (1 << 6));
+ idle = !((OMAP_MCBSP_READ(io_base, SPCR2) |
+ OMAP_MCBSP_READ(io_base, SPCR1)) & 1);
+
+ if (idle) {
+ /* Start the sample generator */
+ w = OMAP_MCBSP_READ(io_base, SPCR2);
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w | (1 << 6));
+ }
/* Enable transmitter and receiver */
w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w | 1);
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w | (tx & 1));
w = OMAP_MCBSP_READ(io_base, SPCR1);
- OMAP_MCBSP_WRITE(io_base, SPCR1, w | 1);
+ OMAP_MCBSP_WRITE(io_base, SPCR1, w | (rx & 1));
udelay(100);
- /* Start frame sync */
- w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w | (1 << 7));
+ if (idle) {
+ /* Start frame sync */
+ w = OMAP_MCBSP_READ(io_base, SPCR2);
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w | (1 << 7));
+ }
/* Dump McBSP Regs */
omap_mcbsp_dump_reg(id);
}
EXPORT_SYMBOL(omap_mcbsp_start);
-void omap_mcbsp_stop(unsigned int id)
+void omap_mcbsp_stop(unsigned int id, int tx, int rx)
{
struct omap_mcbsp *mcbsp;
void __iomem *io_base;
+ int idle;
u16 w;
if (!omap_mcbsp_check_valid_id(id)) {
@@ -386,15 +395,20 @@ void omap_mcbsp_stop(unsigned int id)
/* Reset transmitter */
w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w & ~(1));
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w & ~(tx & 1));
/* Reset receiver */
w = OMAP_MCBSP_READ(io_base, SPCR1);
- OMAP_MCBSP_WRITE(io_base, SPCR1, w & ~(1));
+ OMAP_MCBSP_WRITE(io_base, SPCR1, w & ~(rx & 1));
- /* Reset the sample rate generator */
- w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w & ~(1 << 6));
+ idle = !((OMAP_MCBSP_READ(io_base, SPCR2) |
+ OMAP_MCBSP_READ(io_base, SPCR1)) & 1);
+
+ if (idle) {
+ /* Reset the sample rate generator */
+ w = OMAP_MCBSP_READ(io_base, SPCR2);
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w & ~(1 << 6));
+ }
}
EXPORT_SYMBOL(omap_mcbsp_stop);