text: /*
   * rt5514-spi.c  --  RT5514 SPI driver
   *
   * Copyright 2015 Realtek Semiconductor Corp.
   * Author: Oder Chiou <oder_chiou@realtek.com>
   *
   * 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.
   */
  
  #include <linux/module.h>
  #include <linux/input.h>
  #include <linux/spi/spi.h>
  #include <linux/device.h>
  #include <linux/init.h>
  #include <linux/delay.h>
  #include <linux/interrupt.h>
  #include <linux/irq.h>
  #include <linux/slab.h>
  #include <linux/gpio.h>
  #include <linux/sched.h>
  #include <linux/uaccess.h>
  #include <linux/regulator/consumer.h>
  #include <linux/pm_qos.h>
  #include <linux/sysfs.h>
  #include <linux/clk.h>
  #include <sound/core.h>
  #include <sound/pcm.h>
  #include <sound/pcm_params.h>
  #include <sound/soc.h>
  #include <sound/soc-dapm.h>
  #include <sound/initval.h>
  #include <sound/tlv.h>
  
  #include "rt5514-spi.h"
  
  #define DRV_NAME "rt5514-spi"
  
  static struct spi_device *rt5514_spi;
  
  struct rt5514_dsp {
  	struct device *dev;
  	struct delayed_work copy_work;
  	struct mutex dma_lock;
  	struct snd_pcm_substream *substream;
  	unsigned int buf_base, buf_limit, buf_rp;
  	size_t buf_size, get_size, dma_offset;
  };
  
  static const struct snd_pcm_hardware rt5514_spi_pcm_hardware = {
  	.info			= SNDRV_PCM_INFO_MMAP |
  				  SNDRV_PCM_INFO_MMAP_VALID |
  				  SNDRV_PCM_INFO_INTERLEAVED,
  	.formats		= SNDRV_PCM_FMTBIT_S16_LE,
  	.period_bytes_min	= PAGE_SIZE,
  	.period_bytes_max	= 0x20000 / 8,
  	.periods_min		= 8,
  	.periods_max		= 8,
  	.channels_min		= 1,
  	.channels_max		= 1,
  	.buffer_bytes_max	= 0x20000,
  };
  
  static struct snd_soc_dai_driver rt5514_spi_dai = {
  	.name = "rt5514-dsp-cpu-dai",
  	.id = 0,
  	.capture = {
  		.stream_name = "DSP Capture",
  		.channels_min = 1,
  		.channels_max = 1,
  		.rates = SNDRV_PCM_RATE_16000,
  		.formats = SNDRV_PCM_FMTBIT_S16_LE,
  	},
  };
  
  static void rt5514_spi_copy_work(struct work_struct *work)
  {
  	struct rt5514_dsp *rt5514_dsp =
  		container_of(work, struct rt5514_dsp, copy_work.work);
  	struct snd_pcm_runtime *runtime;
  	size_t period_bytes, truncated_bytes = 0;
  	unsigned int cur_wp, remain_data;
  	u8 buf[8];
  
  	mutex_lock(&rt5514_dsp->dma_lock);
  	if (!rt5514_dsp->substream) {
  		dev_err(rt5514_dsp->dev, "No pcm substream\n");
  		goto done;
  	}
  
  	runtime = rt5514_dsp->substream->runtime;
  	period_bytes = snd_pcm_lib_period_bytes(rt5514_dsp->substream);
  
  	if (rt5514_dsp->get_size >= rt5514_dsp->buf_size) {
  		rt5514_spi_burst_read(RT5514_BUFFER_VOICE_WP, (u8 *)&buf,
  			sizeof(buf));
  		cur_wp = buf[0] | buf[1] << 8 | buf[2] << 16 |
  					buf[3] << 24;
  
  		if (cur_wp >= rt5514_dsp->buf_rp)
  			remain_data = (cur_wp - rt5514_dsp->buf_rp);
  		else
  			remain_data =
  				(rt5514_dsp->buf_limit - rt5514_dsp->buf_rp) +
  				(cur_wp - rt5514_dsp->buf_base);
  
  		if (remain_data < period_bytes) {
  			schedule_delayed_work(&rt5514_dsp->copy_work, 5);
  			goto done;
  		}
  	}
  
  	if (rt5514_dsp->buf_rp + period_bytes <= rt5514_dsp->buf_limit) {
  		rt5514_spi_burst_read(rt5514_dsp->buf_rp,
  			runtime->dma_area + rt5514_dsp->dma_offset,
  			period_bytes);
  
  		if (rt5514_dsp->buf_rp + period_bytes == rt5514_dsp->buf_limit)
  			rt5514_dsp->buf_rp = rt5514_dsp->buf_base;
  		else
  			rt5514_dsp->buf_rp += period_bytes;
  	} else {
  		truncated_bytes = rt5514_dsp->buf_limit - rt5514_dsp->buf_rp;
  		rt5514_spi_burst_read(rt5514_dsp->buf_rp,
  			runtime->dma_area + rt5514_dsp->dma_offset,
  			truncated_bytes);
  
  		rt5514_spi_burst_read(rt5514_dsp->buf_base,
  			runtime->dma_area + rt5514_dsp->dma_offset +
  			truncated_bytes, period_bytes - truncated_bytes);
  
  		rt5514_dsp->buf_rp = rt5514_dsp->buf_base + period_bytes -
  			truncated_bytes;
  	}
  
  	rt5514_dsp->get_size += period_bytes;
  	rt5514_dsp->dma_offset += period_bytes;
  	if (rt5514_dsp->dma_offset >= runtime->dma_bytes)
  		rt5514_dsp->dma_offset = 0;
  
  	snd_pcm_period_elapsed(rt5514_dsp->substream);
  
  	schedule_delayed_work(&rt5514_dsp->copy_work, 5);
  
  done:
  	mutex_unlock(&rt5514_dsp->dma_lock);
  }
  
  static void rt5514_schedule_copy(struct rt5514_dsp *rt5514_dsp)
  {
  	size_t period_bytes;
  	u8 buf[8];
  
  	if (!rt5514_dsp->substream)
  		return;
  
  	period_bytes = snd_pcm_lib_period_bytes(rt5514_dsp->substream);
  	rt5514_dsp->get_size = 0;
  
  	/**
  	 * The address area x1800XXXX is the register address, and it cannot
  	 * support spi burst read perfectly. So we use the spi burst read
  	 * individually to make sure the data correctly.
  	 */
  	rt5514_spi_burst_read(RT5514_BUFFER_VOICE_BASE, (u8 *)&buf,
  		sizeof(buf));
  	rt5514_dsp->buf_base = buf[0] | buf[1] << 8 | buf[2] << 16 |
  				buf[3] << 24;
  
  	rt5514_spi_burst_read(RT5514_BUFFER_VOICE_LIMIT, (u8 *)&buf,
  		sizeof(buf));
  	rt5514_dsp->buf_limit = buf[0] | buf[1] << 8 | buf[2] << 16 |
  				buf[3] << 24;
  
  	rt5514_spi_burst_read(RT5514_BUFFER_VOICE_WP, (u8 *)&buf,
  		sizeof(buf));
  	rt5514_dsp->buf_rp = buf[0] | buf[1] << 8 | buf[2] << 16 |
  				buf[3] << 24;
  
  	if (rt5514_dsp->buf_rp % 8)
  		rt5514_dsp->buf_rp = (rt5514_dsp->buf_rp / 8) * 8;
  
  	rt5514_dsp->buf_size = rt5514_dsp->buf_limit - rt5514_dsp->buf_base;
  
  	if (rt5514_dsp->buf_size % period_bytes)
  		rt5514_dsp->buf_size = (rt5514_dsp->buf_size / period_bytes) *
  			period_bytes;
  
  	if (rt5514_dsp->buf_base && rt5514_dsp->buf_limit &&
  		rt5514_dsp->buf_rp && rt5514_dsp->buf_size)
  		schedule_delayed_work(&rt5514_dsp->copy_work, 0);
  }
  
  static irqreturn_t rt5514_spi_irq(int irq, void *data)
  {
  	struct rt5514_dsp *rt5514_dsp = data;
  
  	rt5514_schedule_copy(rt5514_dsp);
  
  	return IRQ_HANDLED;
  }
  
  /* PCM for streaming audio from the DSP buffer */
  static int rt5514_spi_pcm_open(struct snd_pcm_substream *substream)
  {
  	snd_soc_set_runtime_hwparams(substream, &rt5514_spi_pcm_hardware);
  
  	return 0;
  }
  
  static int rt5514_spi_hw_params(struct snd_pcm_substream *substream,
  			       struct snd_pcm_hw_params *hw_params)
  {
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, DRV_NAME);
  	struct rt5514_dsp *rt5514_dsp =
  		snd_soc_component_get_drvdata(component);
  	int ret;
  	u8 buf[8];
  
  	mutex_lock(&rt5514_dsp->dma_lock);
  	ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
  			params_buffer_bytes(hw_params));
  	rt5514_dsp->substream = substream;
  	rt5514_dsp->dma_offset = 0;
  
  	/* Read IRQ status and schedule copy accordingly. */
  	rt5514_spi_burst_read(RT5514_IRQ_CTRL, (u8 *)&buf, sizeof(buf));
  	if (buf[0] & RT5514_IRQ_STATUS_BIT)
  		rt5514_schedule_copy(rt5514_dsp);
  
  	mutex_unlock(&rt5514_dsp->dma_lock);
  
  	return ret;
  }
  
  static int rt5514_spi_hw_free(struct snd_pcm_substream *substream)
  {
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, DRV_NAME);
  	struct rt5514_dsp *rt5514_dsp =
  		snd_soc_component_get_drvdata(component);
  
  	mutex_lock(&rt5514_dsp->dma_lock);
  	rt5514_dsp->substream = NULL;
  	mutex_unlock(&rt5514_dsp->dma_lock);
  
  	cancel_delayed_work_sync(&rt5514_dsp->copy_work);
  
  	return snd_pcm_lib_free_vmalloc_buffer(substream);
  }
  
  static snd_pcm_uframes_t rt5514_spi_pcm_pointer(
  		struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, DRV_NAME);
  	struct rt5514_dsp *rt5514_dsp =
  		snd_soc_component_get_drvdata(component);
  
  	return bytes_to_frames(runtime, rt5514_dsp->dma_offset);
  }
  
  static const struct snd_pcm_ops rt5514_spi_pcm_ops = {
  	.open		= rt5514_spi_pcm_open,
  	.hw_params	= rt5514_spi_hw_params,
  	.hw_free	= rt5514_spi_hw_free,
  	.pointer	= rt5514_spi_pcm_pointer,
  	.page		= snd_pcm_lib_get_vmalloc_page,
  };
  
  static int rt5514_spi_pcm_probe(struct snd_soc_component *component)
  {
  	struct rt5514_dsp *rt5514_dsp;
  	int ret;
  
  	rt5514_dsp = devm_kzalloc(component->dev, sizeof(*rt5514_dsp),
  			GFP_KERNEL);
  	if (!rt5514_dsp)
  		return -ENOMEM;
  
  	rt5514_dsp->dev = &rt5514_spi->dev;
  	mutex_init(&rt5514_dsp->dma_lock);
  	INIT_DELAYED_WORK(&rt5514_dsp->copy_work, rt5514_spi_copy_work);
  	snd_soc_component_set_drvdata(component, rt5514_dsp);
  
  	if (rt5514_spi->irq) {
  		ret = devm_request_threaded_irq(&rt5514_spi->dev,
  			rt5514_spi->irq, NULL, rt5514_spi_irq,
  			IRQF_TRIGGER_RISING | IRQF_ONESHOT, "rt5514-spi",
  			rt5514_dsp);
  		if (ret)
  			dev_err(&rt5514_spi->dev,
  				"%s Failed to reguest IRQ: %d\n", __func__,
  				ret);
  		else
  			device_init_wakeup(rt5514_dsp->dev, true);
  	}
  
  	return 0;
  }
  
  static const struct snd_soc_component_driver rt5514_spi_component = {
  	.name  = DRV_NAME,
  	.probe = rt5514_spi_pcm_probe,
  	.ops = &rt5514_spi_pcm_ops,
  };
  
  /**
   * rt5514_spi_burst_read - Read data from SPI by rt5514 address.
   * @addr: Start address.
   * @rxbuf: Data Buffer for reading.
   * @len: Data length, it must be a multiple of 8.
   *
   *
   * Returns true for success.
   */
  int rt5514_spi_burst_read(unsigned int addr, u8 *rxbuf, size_t len)
  {
  	u8 spi_cmd = RT5514_SPI_CMD_BURST_READ;
  	int status;
  	u8 write_buf[8];
  	unsigned int i, end, offset = 0;
  
  	struct spi_message message;
  	struct spi_transfer x[3];
  
  	while (offset < len) {
  		if (offset + RT5514_SPI_BUF_LEN <= len)
  			end = RT5514_SPI_BUF_LEN;
  		else
  			end = len % RT5514_SPI_BUF_LEN;
  
  		write_buf[0] = spi_cmd;
  		write_buf[1] = ((addr + offset) & 0xff000000) >> 24;
  		write_buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
  		write_buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
  		write_buf[4] = ((addr + offset) & 0x000000ff) >> 0;
  
  		spi_message_init(&message);
  		memset(x, 0, sizeof(x));
  
  		x[0].len = 5;
  		x[0].tx_buf = write_buf;
  		spi_message_add_tail(&x[0], &message);
  
  		x[1].len = 4;
  		x[1].tx_buf = write_buf;
  		spi_message_add_tail(&x[1], &message);
  
  		x[2].len = end;
  		x[2].rx_buf = rxbuf + offset;
  		spi_message_add_tail(&x[2], &message);
  
  		status = spi_sync(rt5514_spi, &message);
  
  		if (status)
  			return false;
  
  		offset += RT5514_SPI_BUF_LEN;
  	}
  
  	for (i = 0; i < len; i += 8) {
  		write_buf[0] = rxbuf[i + 0];
  		write_buf[1] = rxbuf[i + 1];
  		write_buf[2] = rxbuf[i + 2];
  		write_buf[3] = rxbuf[i + 3];
  		write_buf[4] = rxbuf[i + 4];
  		write_buf[5] = rxbuf[i + 5];
  		write_buf[6] = rxbuf[i + 6];
  		write_buf[7] = rxbuf[i + 7];
  
  		rxbuf[i + 0] = write_buf[7];
  		rxbuf[i + 1] = write_buf[6];
  		rxbuf[i + 2] = write_buf[5];
  		rxbuf[i + 3] = write_buf[4];
  		rxbuf[i + 4] = write_buf[3];
  		rxbuf[i + 5] = write_buf[2];
  		rxbuf[i + 6] = write_buf[1];
  		rxbuf[i + 7] = write_buf[0];
  	}
  
  	return true;
  }
  EXPORT_SYMBOL_GPL(rt5514_spi_burst_read);
  
  /**
   * rt5514_spi_burst_write - Write data to SPI by rt5514 address.
   * @addr: Start address.
   * @txbuf: Data Buffer for writng.
   * @len: Data length, it must be a multiple of 8.
   *
   *
   * Returns true for success.
   */
  int rt5514_spi_burst_write(u32 addr, const u8 *txbuf, size_t len)
  {
  	u8 spi_cmd = RT5514_SPI_CMD_BURST_WRITE;
  	u8 *write_buf;
  	unsigned int i, end, offset = 0;
  
  	write_buf = kmalloc(RT5514_SPI_BUF_LEN + 6, GFP_KERNEL);
  
  	if (write_buf == NULL)
  		return -ENOMEM;
  
  	while (offset < len) {
  		if (offset + RT5514_SPI_BUF_LEN <= len)
  			end = RT5514_SPI_BUF_LEN;
  		else
  			end = len % RT5514_SPI_BUF_LEN;
  
  		write_buf[0] = spi_cmd;
  		write_buf[1] = ((addr + offset) & 0xff000000) >> 24;
  		write_buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
  		write_buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
  		write_buf[4] = ((addr + offset) & 0x000000ff) >> 0;
  
  		for (i = 0; i < end; i += 8) {
  			write_buf[i + 12] = txbuf[offset + i + 0];
  			write_buf[i + 11] = txbuf[offset + i + 1];
  			write_buf[i + 10] = txbuf[offset + i + 2];
  			write_buf[i +  9] = txbuf[offset + i + 3];
  			write_buf[i +  8] = txbuf[offset + i + 4];
  			write_buf[i +  7] = txbuf[offset + i + 5];
  			write_buf[i +  6] = txbuf[offset + i + 6];
  			write_buf[i +  5] = txbuf[offset + i + 7];
  		}
  
  		write_buf[end + 5] = spi_cmd;
  
  		spi_write(rt5514_spi, write_buf, end + 6);
  
  		offset += RT5514_SPI_BUF_LEN;
  	}
  
  	kfree(write_buf);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(rt5514_spi_burst_write);
  
  static int rt5514_spi_probe(struct spi_device *spi)
  {
  	int ret;
  
  	rt5514_spi = spi;
  
  	ret = devm_snd_soc_register_component(&spi->dev,
  					      &rt5514_spi_component,
  					      &rt5514_spi_dai, 1);
  	if (ret < 0) {
  		dev_err(&spi->dev, "Failed to register component.\n");
  		return ret;
  	}
  
  	return 0;
  }
  
  static int __maybe_unused rt5514_suspend(struct device *dev)
  {
  	int irq = to_spi_device(dev)->irq;
  
  	if (device_may_wakeup(dev))
  		enable_irq_wake(irq);
  
  	return 0;
  }
  
  static int __maybe_unused rt5514_resume(struct device *dev)
  {
  	struct snd_soc_component *component = snd_soc_lookup_component(dev, DRV_NAME);
  	struct rt5514_dsp *rt5514_dsp =
  		snd_soc_component_get_drvdata(component);
  	int irq = to_spi_device(dev)->irq;
  	u8 buf[8];
  
  	if (device_may_wakeup(dev))
  		disable_irq_wake(irq);
  
  	if (rt5514_dsp) {
  		if (rt5514_dsp->substream) {
  			rt5514_spi_burst_read(RT5514_IRQ_CTRL, (u8 *)&buf,
  				sizeof(buf));
  			if (buf[0] & RT5514_IRQ_STATUS_BIT)
  				rt5514_schedule_copy(rt5514_dsp);
  		}
  	}
  
  	return 0;
  }
  
  static const struct dev_pm_ops rt5514_pm_ops = {
  	SET_SYSTEM_SLEEP_PM_OPS(rt5514_suspend, rt5514_resume)
  };
  
  static const struct of_device_id rt5514_of_match[] = {
  	{ .compatible = "realtek,rt5514", },
  	{},
  };
  MODULE_DEVICE_TABLE(of, rt5514_of_match);
  
  static struct spi_driver rt5514_spi_driver = {
  	.driver = {
  		.name = "rt5514",
  		.pm = &rt5514_pm_ops,
  		.of_match_table = of_match_ptr(rt5514_of_match),
  	},
  	.probe = rt5514_spi_probe,
  };
  module_spi_driver(rt5514_spi_driver);
  
  MODULE_DESCRIPTION("RT5514 SPI driver");
  MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
  MODULE_LICENSE("GPL v2");
  