storm.c

/*
 * Copyright (c) 2010-2011,2013-2015 The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only 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.
 *
 * storm.c -- ALSA SoC machine driver for QTi ipq806x-based Storm board
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#define STORM_SYSCLK_MULT			4

static int storm_ops_hw_params(struct snd_pcm_substream *substream,
		struct snd_pcm_hw_params *params)
{
	struct snd_soc_pcm_runtime *soc_runtime = substream->private_data;
	struct snd_soc_card *card = soc_runtime->card;
	snd_pcm_format_t format = params_format(params);
	unsigned int rate = params_rate(params);
	unsigned int sysclk_freq;
	int bitwidth, ret;

	bitwidth = snd_pcm_format_width(format);
	if (bitwidth < 0) {
		dev_err(card->dev, "%s() invalid bit width given: %d\n",
				__func__, bitwidth);
		return bitwidth;
	}

	/*
	 * as the CPU DAI is the I2S bus master and no system clock is needed by
	 * the MAX98357a DAC, simply set the system clock to be a constant
	 * multiple of the bit clock for the clock divider
	 */
	sysclk_freq = rate * bitwidth * 2 * STORM_SYSCLK_MULT;

	ret = snd_soc_dai_set_sysclk(soc_runtime->cpu_dai, 0, sysclk_freq, 0);
	if (ret) {
		dev_err(card->dev, "%s() error setting sysclk to %u: %d\n",
				__func__, sysclk_freq, ret);
		return ret;
	}

	return 0;
}

static const struct snd_soc_ops storm_soc_ops = {
	.hw_params	= storm_ops_hw_params,
};

static struct snd_soc_dai_link storm_dai_link = {
	.name		= "Primary",
	.stream_name	= "Primary",
	.codec_dai_name	= "HiFi",
	.ops		= &storm_soc_ops,
};

static int storm_parse_of(struct snd_soc_card *card)
{
	struct snd_soc_dai_link *dai_link = card->dai_link;
	struct device_node *np = card->dev->of_node;

	dai_link->cpu_of_node = of_parse_phandle(np, "cpu", 0);
	if (!dai_link->cpu_of_node) {
		dev_err(card->dev, "%s() error getting cpu phandle\n",
				__func__);
		return -EINVAL;
	}
	dai_link->platform_of_node = dai_link->cpu_of_node;

	dai_link->codec_of_node = of_parse_phandle(np, "codec", 0);
	if (!dai_link->codec_of_node) {
		dev_err(card->dev, "%s() error getting codec phandle\n",
				__func__);
		return -EINVAL;
	}

	return 0;
}

static int storm_platform_probe(struct platform_device *pdev)
{
	struct snd_soc_card *card;
	int ret;

	card = devm_kzalloc(&pdev->dev, sizeof(*card), GFP_KERNEL);
	if (!card)
		return -ENOMEM;

	card->dev = &pdev->dev;
	platform_set_drvdata(pdev, card);

	ret = snd_soc_of_parse_card_name(card, "qcom,model");
	if (ret) {
		dev_err(&pdev->dev, "%s() error parsing card name: %d\n",
				__func__, ret);
		return ret;
	}

	card->dai_link	= &storm_dai_link;
	card->num_links	= 1;

	ret = storm_parse_of(card);
	if (ret) {
		dev_err(&pdev->dev, "%s() error resolving dai links: %d\n",
				__func__, ret);
		return ret;
	}

	ret = devm_snd_soc_register_card(&pdev->dev, card);
	if (ret)
		dev_err(&pdev->dev, "%s() error registering soundcard: %d\n",
				__func__, ret);

	return ret;

}

#ifdef CONFIG_OF
static const struct of_device_id storm_device_id[]  = {
	{ .compatible = "google,storm-audio" },
	{},
};
MODULE_DEVICE_TABLE(of, storm_device_id);
#endif

static struct platform_driver storm_platform_driver = {
	.driver = {
		.name = "storm-audio",
		.of_match_table =
			of_match_ptr(storm_device_id),
	},
	.probe = storm_platform_probe,
};
module_platform_driver(storm_platform_driver);

MODULE_DESCRIPTION("QTi IPQ806x-based Storm Machine Driver");
MODULE_LICENSE("GPL v2");