ARM: OMAP: mcbsp: Move sidetone clock management to mach-omap2/mcbsp.c

Active sidetone requires that McBSP interface clock doesn't idle and there
is no mechanism in hwmod to turn autoidling on/off in runtime. McBSP2 and 3
in OMAP34xx share their interface clock with McBSP sidetone module and
that interface clock must be active when the sidetone is operating.

Sidetone has its own autoidle bit which should keep the interface clock
active but it is broken. Putting the McBSP core to no-idle mode when the
sidetone is active is no good either since it results to higher power
consumption when using the threshold based DMA transfers.

For making the McBSP code more generic, move this sidetone clock management
with fixme comments to mach-omap2/mcbsp.c and pass pointer to it via
platform data.

Signed-off-by: Jarkko Nikula <jhnikula@gmail.com>
Cc: Paul Wamsley <paul@pwsan.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/mcbsp.c b/arch/arm/mach-omap2/mcbsp.c
index d6cce00a730b..92bd5e22a24e 100644
--- a/arch/arm/mach-omap2/mcbsp.c
+++ b/arch/arm/mach-omap2/mcbsp.c
@@ -27,6 +27,13 @@
 
 #include "control.h"
 
+/*
+ * FIXME: Find a mechanism to enable/disable runtime the McBSP ICLK autoidle.
+ * Sidetone needs non-gated ICLK and sidetone autoidle is broken.
+ */
+#include "cm2xxx_3xxx.h"
+#include "cm-regbits-34xx.h"
+
 /* McBSP internal signal muxing functions */
 
 void omap2_mcbsp1_mux_clkr_src(u8 mux)
@@ -102,6 +109,24 @@ int omap2_mcbsp_set_clks_src(u8 id, u8 fck_src_id)
 }
 EXPORT_SYMBOL(omap2_mcbsp_set_clks_src);
 
+static int omap3_enable_st_clock(unsigned int id, bool enable)
+{
+        unsigned int w;
+
+        /*
+         * Sidetone uses McBSP ICLK - which must not idle when sidetones
+         * are enabled or sidetones start sounding ugly.
+         */
+        w = omap2_cm_read_mod_reg(OMAP3430_PER_MOD, CM_AUTOIDLE);
+        if (enable)
+                w &= ~(1 << (id - 2));
+        else
+                w |= 1 << (id - 2);
+        omap2_cm_write_mod_reg(w, OMAP3430_PER_MOD, CM_AUTOIDLE);
+
+        return 0;
+}
+
 struct omap_device_pm_latency omap2_mcbsp_latency[] = {
         {
                 .deactivate_func = omap_device_idle_hwmods,
@@ -151,6 +176,7 @@ static int omap_init_mcbsp(struct omap_hwmod *oh, void *unused)
         if (oh->dev_attr) {
                 oh_device[1] = omap_hwmod_lookup((
                 (struct omap_mcbsp_dev_attr *)(oh->dev_attr))->sidetone);
+                pdata->enable_st_clock = omap3_enable_st_clock;
                 count++;
         }
         pdev = omap_device_build_ss(name, id, oh_device, count, pdata,