ASoC: sti: Add clock adjustement control

Add capability to adjust player clock, for clocks drift management.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

2 files changed, 150 insertions, 1 deletions

diff --git a/sound/soc/sti/uniperif.h b/sound/soc/sti/uniperif.h
index f1e583de3c6f..ee462f7daaff 100644
--- a/sound/soc/sti/uniperif.h
+++ b/sound/soc/sti/uniperif.h
@@ -1175,6 +1175,7 @@ struct uniperif {
         /* Clocks */
         struct clk *clk;
         int mclk;
+        int clk_adj;
 
         /* Runtime data */
         enum uniperif_state state;
@@ -1183,6 +1184,7 @@ struct uniperif {
 
         /* Specific to IEC958 player */
         struct uniperif_iec958_settings stream_settings;
+        struct mutex ctrl_lock; /* For resource updated by stream and controls*/
 
         /*alsa ctrl*/
         struct snd_kcontrol_new *snd_ctrls;
diff --git a/sound/soc/sti/uniperif_player.c b/sound/soc/sti/uniperif_player.c
index d12d0502545e..d990d2c81a5d 100644
--- a/sound/soc/sti/uniperif_player.c
+++ b/sound/soc/sti/uniperif_player.c
@@ -36,6 +36,9 @@
         (UNIPERIF_PLAYER_TYPE_IS_HDMI(p) || \
                 UNIPERIF_PLAYER_TYPE_IS_SPDIF(p))
 
+#define UNIPERIF_PLAYER_CLK_ADJ_MIN  -999999
+#define UNIPERIF_PLAYER_CLK_ADJ_MAX  1000000
+
 /*
  * Note: snd_pcm_hardware is linked to DMA controller but is declared here to
  * integrate  DAI_CPU capability in term of rate and supported channels
@@ -172,6 +175,70 @@ static irqreturn_t uni_player_irq_handler(int irq, void *dev_id)
         return ret;
 }
 
+int uni_player_clk_set_rate(struct uniperif *player, unsigned long rate)
+{
+        int rate_adjusted, rate_achieved, delta, ret;
+        int adjustment = player->clk_adj;
+
+        /*
+         *             a
+         * F = f + --------- * f = f + d
+         *          1000000
+         *
+         *         a
+         * d = --------- * f
+         *      1000000
+         *
+         * where:
+         *   f - nominal rate
+         *   a - adjustment in ppm (parts per milion)
+         *   F - rate to be set in synthesizer
+         *   d - delta (difference) between f and F
+         */
+        if (adjustment < 0) {
+                /* div64_64 operates on unsigned values... */
+                delta = -1;
+                adjustment = -adjustment;
+        } else {
+                delta = 1;
+        }
+        /* 500000 ppm is 0.5, which is used to round up values */
+        delta *= (int)div64_u64((uint64_t)rate *
+                                (uint64_t)adjustment + 500000, 1000000);
+        rate_adjusted = rate + delta;
+
+        /* Adjusted rate should never be == 0 */
+        if (!rate_adjusted)
+                return -EINVAL;
+
+        ret = clk_set_rate(player->clk, rate_adjusted);
+        if (ret < 0)
+                return ret;
+
+        rate_achieved = clk_get_rate(player->clk);
+        if (!rate_achieved)
+                /* If value is 0 means that clock or parent not valid */
+                return -EINVAL;
+
+        /*
+         * Using ALSA's adjustment control, we can modify the rate to be up
+         * to twice as much as requested, but no more
+         */
+        delta = rate_achieved - rate;
+        if (delta < 0) {
+                /* div64_64 operates on unsigned values... */
+                delta = -delta;
+                adjustment = -1;
+        } else {
+                adjustment = 1;
+        }
+        /* Frequency/2 is added to round up result */
+        adjustment *= (int)div64_u64((uint64_t)delta * 1000000 + rate / 2,
+                                     rate);
+        player->clk_adj = adjustment;
+        return 0;
+}
+
 static void uni_player_set_channel_status(struct uniperif *player,
                                           struct snd_pcm_runtime *runtime)
 {
@@ -470,6 +537,78 @@ static int uni_player_prepare_pcm(struct uniperif *player,
         return 0;
 }
 
+/*
+ * uniperif rate adjustement control
+ */
+static int snd_sti_clk_adjustment_info(struct snd_kcontrol *kcontrol,
+                                       struct snd_ctl_elem_info *uinfo)
+{
+        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+        uinfo->count = 1;
+        uinfo->value.integer.min = UNIPERIF_PLAYER_CLK_ADJ_MIN;
+        uinfo->value.integer.max = UNIPERIF_PLAYER_CLK_ADJ_MAX;
+        uinfo->value.integer.step = 1;
+
+        return 0;
+}
+
+static int snd_sti_clk_adjustment_get(struct snd_kcontrol *kcontrol,
+                                      struct snd_ctl_elem_value *ucontrol)
+{
+        struct snd_soc_dai *dai = snd_kcontrol_chip(kcontrol);
+        struct sti_uniperiph_data *priv = snd_soc_dai_get_drvdata(dai);
+        struct uniperif *player = priv->dai_data.uni;
+
+        ucontrol->value.integer.value[0] = player->clk_adj;
+
+        return 0;
+}
+
+static int snd_sti_clk_adjustment_put(struct snd_kcontrol *kcontrol,
+                                      struct snd_ctl_elem_value *ucontrol)
+{
+        struct snd_soc_dai *dai = snd_kcontrol_chip(kcontrol);
+        struct sti_uniperiph_data *priv = snd_soc_dai_get_drvdata(dai);
+        struct uniperif *player = priv->dai_data.uni;
+        int ret = 0;
+
+        if ((ucontrol->value.integer.value[0] < UNIPERIF_PLAYER_CLK_ADJ_MIN) ||
+            (ucontrol->value.integer.value[0] > UNIPERIF_PLAYER_CLK_ADJ_MAX))
+                return -EINVAL;
+
+        mutex_lock(&player->ctrl_lock);
+        player->clk_adj = ucontrol->value.integer.value[0];
+
+        if (player->mclk)
+                ret = uni_player_clk_set_rate(player, player->mclk);
+        mutex_unlock(&player->ctrl_lock);
+
+        return ret;
+}
+
+static struct snd_kcontrol_new uni_player_clk_adj_ctl = {
+        .iface = SNDRV_CTL_ELEM_IFACE_PCM,
+        .name = "PCM Playback Oversampling Freq. Adjustment",
+        .info = snd_sti_clk_adjustment_info,
+        .get = snd_sti_clk_adjustment_get,
+        .put = snd_sti_clk_adjustment_put,
+};
+
+static struct snd_kcontrol_new *snd_sti_ctl[] = {
+        &uni_player_clk_adj_ctl,
+};
+
+static int uni_player_startup(struct snd_pcm_substream *substream,
+                              struct snd_soc_dai *dai)
+{
+        struct sti_uniperiph_data *priv = snd_soc_dai_get_drvdata(dai);
+        struct uniperif *player = priv->dai_data.uni;
+
+        player->clk_adj = 0;
+
+        return 0;
+}
+
 static int uni_player_set_sysclk(struct snd_soc_dai *dai, int clk_id,
                                  unsigned int freq, int dir)
 {
@@ -483,9 +622,11 @@ static int uni_player_set_sysclk(struct snd_soc_dai *dai, int clk_id,
         if (clk_id != 0)
                 return -EINVAL;
 
-        ret = clk_set_rate(player->clk, freq);
+        mutex_lock(&player->ctrl_lock);
+        ret = uni_player_clk_set_rate(player, freq);
         if (!ret)
                 player->mclk = freq;
+        mutex_unlock(&player->ctrl_lock);
 
         return ret;
 }
@@ -816,6 +957,7 @@ static int uni_player_parse_dt(struct platform_device *pdev,
 }
 
 const struct snd_soc_dai_ops uni_player_dai_ops = {
+                .startup = uni_player_startup,
                 .shutdown = uni_player_shutdown,
                 .prepare = uni_player_prepare,
                 .trigger = uni_player_trigger,
@@ -863,6 +1005,8 @@ int uni_player_init(struct platform_device *pdev,
         if (ret < 0)
                 return ret;
 
+        mutex_init(&player->ctrl_lock);
+
         /* Ensure that disabled by default */
         SET_UNIPERIF_CONFIG_BACK_STALL_REQ_DISABLE(player);
         SET_UNIPERIF_CTRL_ROUNDING_OFF(player);
@@ -889,6 +1033,9 @@ int uni_player_init(struct platform_device *pdev,
                                         IEC958_AES4_CON_WORDLEN_24_20;
         }
 
+        player->num_ctrls = ARRAY_SIZE(snd_sti_ctl);
+        player->snd_ctrls = snd_sti_ctl[0];
+
         return 0;
 }
 EXPORT_SYMBOL_GPL(uni_player_init);