ASoC: sta32x: add workaround for ESD reset issue

sta32x resets and loses all configuration during ESD test.
Work around by polling the CONFA register once a second
and restore all coeffcients and registers when CONFA
changes unexpectedly.

Signed-off-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/include/sound/sta32x.h b/include/sound/sta32x.h
index 45d7477..8d93b03 100644 (file)
--- a/include/sound/sta32x.h
+++ b/include/sound/sta32x.h
@@ -29,6 +29,7 @@ struct sta32x_platform_data {
        int ch2_output_mapping;
        int ch3_output_mapping;
        int thermal_conf;
+       int needs_esd_watchdog;
 };
 
 #endif /* __LINUX_SND__STA32X_H */

diff --git a/sound/soc/codecs/sta32x.c b/sound/soc/codecs/sta32x.c
index 97091e3..3b0deaf 100644 (file)
--- a/sound/soc/codecs/sta32x.c
+++ b/sound/soc/codecs/sta32x.c
@@ -27,6 +27,7 @@
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
+#include <linux/workqueue.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -80,6 +81,8 @@ struct sta32x_priv {
        unsigned int format;
 
        u32 coef_shadow[STA32X_COEF_COUNT];
+       struct delayed_work watchdog_work;
+       int shutdown;
 };
 
 static const DECLARE_TLV_DB_SCALE(mvol_tlv, -12700, 50, 1);
@@ -304,6 +307,46 @@ int sta32x_cache_sync(struct snd_soc_codec *codec)
        return rc;
 }
 
+/* work around ESD issue where sta32x resets and loses all configuration */
+static void sta32x_watchdog(struct work_struct *work)
+{
+       struct sta32x_priv *sta32x = container_of(work, struct sta32x_priv,
+                                                 watchdog_work.work);
+       struct snd_soc_codec *codec = sta32x->codec;
+       unsigned int confa, confa_cached;
+
+       /* check if sta32x has reset itself */
+       confa_cached = snd_soc_read(codec, STA32X_CONFA);
+       codec->cache_bypass = 1;
+       confa = snd_soc_read(codec, STA32X_CONFA);
+       codec->cache_bypass = 0;
+       if (confa != confa_cached) {
+               codec->cache_sync = 1;
+               sta32x_cache_sync(codec);
+       }
+
+       if (!sta32x->shutdown)
+               schedule_delayed_work(&sta32x->watchdog_work,
+                                     round_jiffies_relative(HZ));
+}
+
+static void sta32x_watchdog_start(struct sta32x_priv *sta32x)
+{
+       if (sta32x->pdata->needs_esd_watchdog) {
+               sta32x->shutdown = 0;
+               schedule_delayed_work(&sta32x->watchdog_work,
+                                     round_jiffies_relative(HZ));
+       }
+}
+
+static void sta32x_watchdog_stop(struct sta32x_priv *sta32x)
+{
+       if (sta32x->pdata->needs_esd_watchdog) {
+               sta32x->shutdown = 1;
+               cancel_delayed_work_sync(&sta32x->watchdog_work);
+       }
+}
+
 #define SINGLE_COEF(xname, index) \
 {      .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, \
        .info = sta32x_coefficient_info, \
@@ -714,6 +757,7 @@ static int sta32x_set_bias_level(struct snd_soc_codec *codec,
                        }
 
                        sta32x_cache_sync(codec);
+                       sta32x_watchdog_start(sta32x);
                }
 
                /* Power up to mute */
@@ -730,7 +774,7 @@ static int sta32x_set_bias_level(struct snd_soc_codec *codec,
                                    STA32X_CONFF_PWDN | STA32X_CONFF_EAPD,
                                    STA32X_CONFF_PWDN);
                msleep(300);
-
+               sta32x_watchdog_stop(sta32x);
                regulator_bulk_disable(ARRAY_SIZE(sta32x->supplies),
                                       sta32x->supplies);
                break;
@@ -863,6 +907,9 @@ static int sta32x_probe(struct snd_soc_codec *codec)
        sta32x->coef_shadow[60] = 0x400000;
        sta32x->coef_shadow[61] = 0x400000;
 
+       if (sta32x->pdata->needs_esd_watchdog)
+               INIT_DELAYED_WORK(&sta32x->watchdog_work, sta32x_watchdog);
+
        sta32x_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
        /* Bias level configuration will have done an extra enable */
        regulator_bulk_disable(ARRAY_SIZE(sta32x->supplies), sta32x->supplies);
@@ -879,6 +926,7 @@ static int sta32x_remove(struct snd_soc_codec *codec)
 {
        struct sta32x_priv *sta32x = snd_soc_codec_get_drvdata(codec);
 
+       sta32x_watchdog_stop(sta32x);
        sta32x_set_bias_level(codec, SND_SOC_BIAS_OFF);
        regulator_bulk_disable(ARRAY_SIZE(sta32x->supplies), sta32x->supplies);
        regulator_bulk_free(ARRAY_SIZE(sta32x->supplies), sta32x->supplies);