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authorThomas Niederprüm <niederp@physik.uni-kl.de>2015-02-21 20:11:29 +0300
committerMark Brown <broonie@kernel.org>2015-02-26 05:48:49 +0300
commit8af4baa7087a0ae74c6ee29d4d979a60e14b119e (patch)
tree1e76ae6b4873c8593c6214e91860a0e7d17cace9 /sound/soc/omap
parentfb5ab7296a2bea17c38fae48af2808a07049ac90 (diff)
downloadlinux-8af4baa7087a0ae74c6ee29d4d979a60e14b119e.tar.xz
ASoC: OMAP: mcbsp: Fix CLKX and CLKR pinmux when used as inputs
This patch fixes faulty behaviour in a setup where the input clock for the SRG is fed through the CLKR/CLKX pin but the McBSP is configured to be master (SND_SOC_DAIFMT_CBS_CFS). In that case of course CLKR/CLKX must not be configured as output pin. Otherwise the input clock is messed up horribly. This patch makes it possible to use the CLKR/CLKX pin rather than CLKS to inject a reference clock in setups where McBSP is master and not both rx and tx are used. However for this to work it has to be ensured that set_dai_sysclk() is called after set_dai_fmt(). This was tested on a beagleboard-xm using McBSP1 to drive a i2s DAC through the tx lines (CLKX,FSX,DX). Using this patch the CLKR pin is used to inject an external reference clock. Signed-off-by: Thomas Niederprüm <niederp@physik.uni-kl.de> Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'sound/soc/omap')
-rw-r--r--sound/soc/omap/omap-mcbsp.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index c7eb9dd67f60..fd99d89de6a8 100644
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -530,8 +530,19 @@ static int omap_mcbsp_dai_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
case OMAP_MCBSP_SYSCLK_CLKX_EXT:
regs->srgr2 |= CLKSM;
+ regs->pcr0 |= SCLKME;
+ /*
+ * If McBSP is master but yet the CLKX/CLKR pin drives the SRG,
+ * disable output on those pins. This enables to inject the
+ * reference clock through CLKX/CLKR. For this to work
+ * set_dai_sysclk() _needs_ to be called after set_dai_fmt().
+ */
+ regs->pcr0 &= ~CLKXM;
+ break;
case OMAP_MCBSP_SYSCLK_CLKR_EXT:
regs->pcr0 |= SCLKME;
+ /* Disable ouput on CLKR pin in master mode */
+ regs->pcr0 &= ~CLKRM;
break;
default:
err = -ENODEV;