// SPDX-License-Identifier: GPL-2.0-or-later /* * atmel_ssc_dai.c -- ALSA SoC ATMEL SSC Audio Layer Platform driver * * Copyright (C) 2005 SAN People * Copyright (C) 2008 Atmel * * Author: Sedji Gaouaou <[email protected]> * ATMEL CORP. * * Based on at91-ssc.c by * Frank Mandarino <[email protected]> * Based on pxa2xx Platform drivers by * Liam Girdwood <[email protected]> */ #include <linux/init.h> #include <linux/module.h> #include <linux/interrupt.h> #include <linux/device.h> #include <linux/delay.h> #include <linux/clk.h> #include <linux/atmel_pdc.h> #include <linux/atmel-ssc.h> #include <sound/core.h> #include <sound/pcm.h> #include <sound/pcm_params.h> #include <sound/initval.h> #include <sound/soc.h> #include "atmel-pcm.h" #include "atmel_ssc_dai.h" #define NUM_SSC_DEVICES … /* * SSC PDC registers required by the PCM DMA engine. */ static struct atmel_pdc_regs pdc_tx_reg = …; static struct atmel_pdc_regs pdc_rx_reg = …; /* * SSC & PDC status bits for transmit and receive. */ static struct atmel_ssc_mask ssc_tx_mask = …; static struct atmel_ssc_mask ssc_rx_mask = …; /* * DMA parameters. */ static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = …; static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = …; /* * SSC interrupt handler. Passes PDC interrupts to the DMA * interrupt handler in the PCM driver. */ static irqreturn_t atmel_ssc_interrupt(int irq, void *dev_id) { … } /* * When the bit clock is input, limit the maximum rate according to the * Serial Clock Ratio Considerations section from the SSC documentation: * * The Transmitter and the Receiver can be programmed to operate * with the clock signals provided on either the TK or RK pins. * This allows the SSC to support many slave-mode data transfers. * In this case, the maximum clock speed allowed on the RK pin is: * - Peripheral clock divided by 2 if Receiver Frame Synchro is input * - Peripheral clock divided by 3 if Receiver Frame Synchro is output * In addition, the maximum clock speed allowed on the TK pin is: * - Peripheral clock divided by 6 if Transmit Frame Synchro is input * - Peripheral clock divided by 2 if Transmit Frame Synchro is output * * When the bit clock is output, limit the rate according to the * SSC divider restrictions. */ static int atmel_ssc_hw_rule_rate(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule) { … } /*-------------------------------------------------------------------------*\ * DAI functions \*-------------------------------------------------------------------------*/ /* * Startup. Only that one substream allowed in each direction. */ static int atmel_ssc_startup(struct snd_pcm_substream *substream, struct snd_soc_dai *dai) { … } /* * Shutdown. Clear DMA parameters and shutdown the SSC if there * are no other substreams open. */ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream, struct snd_soc_dai *dai) { … } /* * Record the DAI format for use in hw_params(). */ static int atmel_ssc_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt) { … } /* * Record SSC clock dividers for use in hw_params(). */ static int atmel_ssc_set_dai_clkdiv(struct snd_soc_dai *cpu_dai, int div_id, int div) { … } /* Is the cpu-dai master of the frame clock? */ static int atmel_ssc_cfs(struct atmel_ssc_info *ssc_p) { … } /* Is the cpu-dai master of the bit clock? */ static int atmel_ssc_cbs(struct atmel_ssc_info *ssc_p) { … } /* * Configure the SSC. */ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params, struct snd_soc_dai *dai) { … } static int atmel_ssc_prepare(struct snd_pcm_substream *substream, struct snd_soc_dai *dai) { … } static int atmel_ssc_trigger(struct snd_pcm_substream *substream, int cmd, struct snd_soc_dai *dai) { … } static int atmel_ssc_suspend(struct snd_soc_component *component) { … } static int atmel_ssc_resume(struct snd_soc_component *component) { … } #define ATMEL_SSC_FORMATS … static const struct snd_soc_dai_ops atmel_ssc_dai_ops = …; static struct snd_soc_dai_driver atmel_ssc_dai = …; static const struct snd_soc_component_driver atmel_ssc_component = …; static int asoc_ssc_init(struct device *dev) { … } /** * atmel_ssc_set_audio - Allocate the specified SSC for audio use. * @ssc_id: SSD ID in [0, NUM_SSC_DEVICES[ */ int atmel_ssc_set_audio(int ssc_id) { … } EXPORT_SYMBOL_GPL(…); void atmel_ssc_put_audio(int ssc_id) { … } EXPORT_SYMBOL_GPL(…); /* Module information */ MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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