Allo Piano DAC boards: Initial 2 channel (stereo) support (#1645)

Add initial 2 channel (stereo) support for Allo Piano DAC (2.0/2.1) boards,
using allo-piano-dac-pcm512x-audio overlay and allo-piano-dac ALSA ASoC
machine driver.

NB. The initial support is 2 channel (stereo) ONLY!
(The Piano DAC 2.1 will only support 2 channel (stereo) left/right output,
 pending an update to the upstream pcm512x codec driver, which will have
 to be submitted via upstream. With the initial downstream support,
 provided by this patch, the Piano DAC 2.1 subwoofer outputs will
 not function.)

Signed-off-by: Baswaraj K <jaikumar@cem-solutions.net>
Signed-off-by: Clive Messer <clive.messer@digitaldreamtime.co.uk>
Tested-by: Clive Messer <clive.messer@digitaldreamtime.co.uk>
ASoC: allo-piano-dac: fix S24_LE format

Remove set_bclk_ratio call so 24-bit data is transmitted in
24 bclk cycles.

Also remove hw_params and ops as they are no longer needed.

Signed-off-by: Matthias Reichl <hias@horus.com>

diff --git a/sound/soc/bcm/allo-piano-dac.c b/sound/soc/bcm/allo-piano-dac.c
new file mode 100644 (file)
index 0000000..df58317
--- /dev/null
+++ b/sound/soc/bcm/allo-piano-dac.c
@@ -0,0 +1,120 @@
+/*
+ * ALSA ASoC Machine Driver for Allo Piano DAC
+ *
+ * Author:     Baswaraj K <jaikumar@cem-solutions.net>
+ *             Copyright 2016
+ *             based on code by Daniel Matuschek <info@crazy-audio.com>
+ *             based on code by Florian Meier <florian.meier@koalo.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+
+static bool digital_gain_0db_limit = true;
+
+static int snd_allo_piano_dac_init(struct snd_soc_pcm_runtime *rtd)
+{
+       if (digital_gain_0db_limit) {
+               int ret;
+               struct snd_soc_card *card = rtd->card;
+
+               ret = snd_soc_limit_volume(card, "Digital Playback Volume",
+                                          207);
+               if (ret < 0)
+                       dev_warn(card->dev, "Failed to set volume limit: %d\n",
+                                ret);
+       }
+
+       return 0;
+}
+
+static struct snd_soc_dai_link snd_allo_piano_dac_dai[] = {
+{
+       .name           = "Piano DAC",
+       .stream_name    = "Piano DAC HiFi",
+       .cpu_dai_name   = "bcm2708-i2s.0",
+       .codec_dai_name = "pcm512x-hifi",
+       .platform_name  = "bcm2708-i2s.0",
+       .codec_name     = "pcm512x.1-004c",
+       .dai_fmt        = SND_SOC_DAIFMT_I2S |
+                         SND_SOC_DAIFMT_NB_NF |
+                         SND_SOC_DAIFMT_CBS_CFS,
+       .init           = snd_allo_piano_dac_init,
+},
+};
+
+/* audio machine driver */
+static struct snd_soc_card snd_allo_piano_dac = {
+       .name         = "PianoDAC",
+       .owner        = THIS_MODULE,
+       .dai_link     = snd_allo_piano_dac_dai,
+       .num_links    = ARRAY_SIZE(snd_allo_piano_dac_dai),
+};
+
+static int snd_allo_piano_dac_probe(struct platform_device *pdev)
+{
+       int ret = 0;
+
+       snd_allo_piano_dac.dev = &pdev->dev;
+
+       if (pdev->dev.of_node) {
+               struct device_node *i2s_node;
+               struct snd_soc_dai_link *dai;
+
+               dai = &snd_allo_piano_dac_dai[0];
+               i2s_node = of_parse_phandle(pdev->dev.of_node,
+                                           "i2s-controller", 0);
+
+               if (i2s_node) {
+                       dai->cpu_dai_name = NULL;
+                       dai->cpu_of_node = i2s_node;
+                       dai->platform_name = NULL;
+                       dai->platform_of_node = i2s_node;
+               }
+
+               digital_gain_0db_limit = !of_property_read_bool(
+                       pdev->dev.of_node, "allo,24db_digital_gain");
+       }
+
+       ret = devm_snd_soc_register_card(&pdev->dev, &snd_allo_piano_dac);
+       if (ret && ret != -EPROBE_DEFER)
+               dev_err(&pdev->dev,
+                       "snd_soc_register_card() failed: %d\n", ret);
+
+       return ret;
+}
+
+static const struct of_device_id snd_allo_piano_dac_of_match[] = {
+       { .compatible = "allo,piano-dac", },
+       { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, snd_allo_piano_dac_of_match);
+
+static struct platform_driver snd_allo_piano_dac_driver = {
+       .driver = {
+               .name   = "snd-allo-piano-dac",
+               .owner  = THIS_MODULE,
+               .of_match_table = snd_allo_piano_dac_of_match,
+       },
+       .probe          = snd_allo_piano_dac_probe,
+};
+
+module_platform_driver(snd_allo_piano_dac_driver);
+
+MODULE_AUTHOR("Baswaraj K <jaikumar@cem-solutions.net>");
+MODULE_DESCRIPTION("ALSA ASoC Machine Driver for Allo Piano DAC");
+MODULE_LICENSE("GPL v2");