text: /*
   * Copyright (c) 2017 - 2018, Nordic Semiconductor ASA
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #include <drivers/spi.h>
  #include <nrfx_spi.h>
  
  #define LOG_DOMAIN "spi_nrfx_spi"
  #define LOG_LEVEL CONFIG_SPI_LOG_LEVEL
  #include <logging/log.h>
  LOG_MODULE_REGISTER(spi_nrfx_spi);
  
  #include "spi_context.h"
  
  struct spi_nrfx_data {
  	struct spi_context ctx;
  	const struct device *dev;
  	size_t chunk_len;
  	bool   busy;
  	bool   initialized;
  };
  
  struct spi_nrfx_config {
  	nrfx_spi_t	  spi;
  	nrfx_spi_config_t def_config;
  };
  
  static void event_handler(const nrfx_spi_evt_t *p_event, void *p_context);
  
  static inline struct spi_nrfx_data *get_dev_data(const struct device *dev)
  {
  	return dev->data;
  }
  
  static inline const struct spi_nrfx_config *get_dev_config(const struct device *dev)
  {
  	return dev->config;
  }
  
  static inline nrf_spi_frequency_t get_nrf_spi_frequency(uint32_t frequency)
  {
  	/* Get the highest supported frequency not exceeding the requested one.
  	 */
  	if (frequency < 250000) {
  		return NRF_SPI_FREQ_125K;
  	} else if (frequency < 500000) {
  		return NRF_SPI_FREQ_250K;
  	} else if (frequency < 1000000) {
  		return NRF_SPI_FREQ_500K;
  	} else if (frequency < 2000000) {
  		return NRF_SPI_FREQ_1M;
  	} else if (frequency < 4000000) {
  		return NRF_SPI_FREQ_2M;
  	} else if (frequency < 8000000) {
  		return NRF_SPI_FREQ_4M;
  	} else {
  		return NRF_SPI_FREQ_8M;
  	}
  }
  
  static inline nrf_spi_mode_t get_nrf_spi_mode(uint16_t operation)
  {
  	if (SPI_MODE_GET(operation) & SPI_MODE_CPOL) {
  		if (SPI_MODE_GET(operation) & SPI_MODE_CPHA) {
  			return NRF_SPI_MODE_3;
  		} else {
  			return NRF_SPI_MODE_2;
  		}
  	} else {
  		if (SPI_MODE_GET(operation) & SPI_MODE_CPHA) {
  			return NRF_SPI_MODE_1;
  		} else {
  			return NRF_SPI_MODE_0;
  		}
  	}
  }
  
  static inline nrf_spi_bit_order_t get_nrf_spi_bit_order(uint16_t operation)
  {
  	if (operation & SPI_TRANSFER_LSB) {
  		return NRF_SPI_BIT_ORDER_LSB_FIRST;
  	} else {
  		return NRF_SPI_BIT_ORDER_MSB_FIRST;
  	}
  }
  
  static int configure(const struct device *dev,
  		     const struct spi_config *spi_cfg)
  {
  	struct spi_nrfx_data *dev_data = get_dev_data(dev);
  	const struct spi_nrfx_config *dev_config = get_dev_config(dev);
  	struct spi_context *ctx = &dev_data->ctx;
  	nrfx_spi_config_t config;
  	nrfx_err_t result;
  
  	if (dev_data->initialized && spi_context_configured(ctx, spi_cfg)) {
  		/* Already configured. No need to do it again. */
  		return 0;
  	}
  
  	if (SPI_OP_MODE_GET(spi_cfg->operation) != SPI_OP_MODE_MASTER) {
  		LOG_ERR("Slave mode is not supported on %s", dev->name);
  		return -EINVAL;
  	}
  
  	if (spi_cfg->operation & SPI_MODE_LOOP) {
  		LOG_ERR("Loopback mode is not supported");
  		return -EINVAL;
  	}
  
  	if ((spi_cfg->operation & SPI_LINES_MASK) != SPI_LINES_SINGLE) {
  		LOG_ERR("Only single line mode is supported");
  		return -EINVAL;
  	}
  
  	if (SPI_WORD_SIZE_GET(spi_cfg->operation) != 8) {
  		LOG_ERR("Word sizes other than 8 bits are not supported");
  		return -EINVAL;
  	}
  
  	if (spi_cfg->frequency < 125000) {
  		LOG_ERR("Frequencies lower than 125 kHz are not supported");
  		return -EINVAL;
  	}
  
  	config = dev_config->def_config;
  
  	config.frequency = get_nrf_spi_frequency(spi_cfg->frequency);
  	config.mode      = get_nrf_spi_mode(spi_cfg->operation);
  	config.bit_order = get_nrf_spi_bit_order(spi_cfg->operation);
  
  	if (dev_data->initialized) {
  		nrfx_spi_uninit(&dev_config->spi);
  		dev_data->initialized = false;
  	}
  
  	result = nrfx_spi_init(&dev_config->spi, &config,
  			       event_handler, dev_data);
  	if (result != NRFX_SUCCESS) {
  		LOG_ERR("Failed to initialize nrfx driver: %08x", result);
  		return -EIO;
  	}
  
  	dev_data->initialized = true;
  
  	ctx->config = spi_cfg;
  	spi_context_cs_configure(ctx);
  
  	return 0;
  }
  
  static void transfer_next_chunk(const struct device *dev)
  {
  	struct spi_nrfx_data *dev_data = get_dev_data(dev);
  	struct spi_context *ctx = &dev_data->ctx;
  	int error = 0;
  
  	size_t chunk_len = spi_context_max_continuous_chunk(ctx);
  
  	if (chunk_len > 0) {
  		nrfx_spi_xfer_desc_t xfer;
  		nrfx_err_t result;
  
  		dev_data->chunk_len = chunk_len;
  
  		xfer.p_tx_buffer = ctx->tx_buf;
  		xfer.tx_length   = spi_context_tx_buf_on(ctx) ? chunk_len : 0;
  		xfer.p_rx_buffer = ctx->rx_buf;
  		xfer.rx_length   = spi_context_rx_buf_on(ctx) ? chunk_len : 0;
  		result = nrfx_spi_xfer(&get_dev_config(dev)->spi, &xfer, 0);
  		if (result == NRFX_SUCCESS) {
  			return;
  		}
  
  		error = -EIO;
  	}
  
  	spi_context_cs_control(ctx, false);
  
  	LOG_DBG("Transaction finished with status %d", error);
  
  	spi_context_complete(ctx, error);
  	dev_data->busy = false;
  }
  
  static void event_handler(const nrfx_spi_evt_t *p_event, void *p_context)
  {
  	struct spi_nrfx_data *dev_data = p_context;
  
  	if (p_event->type == NRFX_SPI_EVENT_DONE) {
  		spi_context_update_tx(&dev_data->ctx, 1, dev_data->chunk_len);
  		spi_context_update_rx(&dev_data->ctx, 1, dev_data->chunk_len);
  
  		transfer_next_chunk(dev_data->dev);
  	}
  }
  
  static int transceive(const struct device *dev,
  		      const struct spi_config *spi_cfg,
  		      const struct spi_buf_set *tx_bufs,
  		      const struct spi_buf_set *rx_bufs,
  		      bool asynchronous,
  		      struct k_poll_signal *signal)
  {
  	struct spi_nrfx_data *dev_data = get_dev_data(dev);
  	int error;
  
  	spi_context_lock(&dev_data->ctx, asynchronous, signal, spi_cfg);
  
  	error = configure(dev, spi_cfg);
  	if (error == 0) {
  		dev_data->busy = true;
  
  		spi_context_buffers_setup(&dev_data->ctx, tx_bufs, rx_bufs, 1);
  		spi_context_cs_control(&dev_data->ctx, true);
  
  		transfer_next_chunk(dev);
  
  		error = spi_context_wait_for_completion(&dev_data->ctx);
  	}
  
  	spi_context_release(&dev_data->ctx, error);
  
  	return error;
  }
  
  static int spi_nrfx_transceive(const struct device *dev,
  			       const struct spi_config *spi_cfg,
  			       const struct spi_buf_set *tx_bufs,
  			       const struct spi_buf_set *rx_bufs)
  {
  	return transceive(dev, spi_cfg, tx_bufs, rx_bufs, false, NULL);
  }
  
  #ifdef CONFIG_SPI_ASYNC
  static int spi_nrfx_transceive_async(const struct device *dev,
  				     const struct spi_config *spi_cfg,
  				     const struct spi_buf_set *tx_bufs,
  				     const struct spi_buf_set *rx_bufs,
  				     struct k_poll_signal *async)
  {
  	return transceive(dev, spi_cfg, tx_bufs, rx_bufs, true, async);
  }
  #endif /* CONFIG_SPI_ASYNC */
  
  static int spi_nrfx_release(const struct device *dev,
  			    const struct spi_config *spi_cfg)
  {
  	struct spi_nrfx_data *dev_data = get_dev_data(dev);
  
  	if (!spi_context_configured(&dev_data->ctx, spi_cfg)) {
  		return -EINVAL;
  	}
  
  	if (dev_data->busy) {
  		return -EBUSY;
  	}
  
  	spi_context_unlock_unconditionally(&dev_data->ctx);
  
  	return 0;
  }
  
  static const struct spi_driver_api spi_nrfx_driver_api = {
  	.transceive = spi_nrfx_transceive,
  #ifdef CONFIG_SPI_ASYNC
  	.transceive_async = spi_nrfx_transceive_async,
  #endif
  	.release = spi_nrfx_release,
  };
  
  
  #ifdef CONFIG_PM_DEVICE
  static int spi_nrfx_pm_control(const struct device *dev,
  			       enum pm_device_action action)
  {
  	int ret = 0;
  	struct spi_nrfx_data *data = get_dev_data(dev);
  	const struct spi_nrfx_config *config = get_dev_config(dev);
  
  	switch (action) {
  	case PM_DEVICE_ACTION_RESUME:
  		/* No action needed at this point, nrfx_spi_init() will be
  		 * called at configuration before the next transfer.
  		 */
  		break;
  
  	case PM_DEVICE_ACTION_SUSPEND:
  		nrfx_spi_uninit(&config->spi);
  		data->initialized = false;
  		break;
  
  	default:
  		ret = -ENOTSUP;
  	}
  
  	return ret;
  }
  #endif /* CONFIG_PM_DEVICE */
  
  /*
   * Current factors requiring use of DT_NODELABEL:
   *
   * - NRFX_SPI_INSTANCE() requires an SoC instance number
   * - soc-instance-numbered kconfig enables
   * - ORC is a SoC-instance-numbered kconfig option instead of a DT property
   */
  
  #define SPI(idx)			DT_NODELABEL(spi##idx)
  #define SPI_PROP(idx, prop)		DT_PROP(SPI(idx), prop)
  
  #define SPI_NRFX_MISO_PULL(idx)				\
  	(SPI_PROP(idx, miso_pull_up)			\
  		? SPI_PROP(idx, miso_pull_down)		\
  			? -1 /* invalid configuration */\
  			: NRF_GPIO_PIN_PULLUP		\
  		: SPI_PROP(idx, miso_pull_down)		\
  			? NRF_GPIO_PIN_PULLDOWN		\
  			: NRF_GPIO_PIN_NOPULL)
  
  #define SPI_NRFX_SPI_DEVICE(idx)					       \
  	BUILD_ASSERT(							       \
  		!SPI_PROP(idx, miso_pull_up) || !SPI_PROP(idx, miso_pull_down),\
  		"SPI"#idx						       \
  		": cannot enable both pull-up and pull-down on MISO line");    \
  	static int spi_##idx##_init(const struct device *dev)		       \
  	{								       \
  		IRQ_CONNECT(DT_IRQN(SPI(idx)), DT_IRQ(SPI(idx), priority),     \
  			    nrfx_isr, nrfx_spi_##idx##_irq_handler, 0);	       \
  		spi_context_unlock_unconditionally(&get_dev_data(dev)->ctx);   \
  		return 0;						       \
  	}								       \
  	static struct spi_nrfx_data spi_##idx##_data = {		       \
  		SPI_CONTEXT_INIT_LOCK(spi_##idx##_data, ctx),		       \
  		SPI_CONTEXT_INIT_SYNC(spi_##idx##_data, ctx),		       \
  		.dev  = DEVICE_DT_GET(SPI(idx)),			       \
  		.busy = false,						       \
  	};								       \
  	static const struct spi_nrfx_config spi_##idx##z_config = {	       \
  		.spi = NRFX_SPI_INSTANCE(idx),				       \
  		.def_config = {						       \
  			.sck_pin   = SPI_PROP(idx, sck_pin),		       \
  			.mosi_pin  = SPI_PROP(idx, mosi_pin),		       \
  			.miso_pin  = SPI_PROP(idx, miso_pin),		       \
  			.ss_pin    = NRFX_SPI_PIN_NOT_USED,		       \
  			.orc       = CONFIG_SPI_##idx##_NRF_ORC,	       \
  			.miso_pull = SPI_NRFX_MISO_PULL(idx),		       \
  		}							       \
  	};								       \
  	DEVICE_DT_DEFINE(SPI(idx),					       \
  		      spi_##idx##_init,					       \
  		      spi_nrfx_pm_control,				       \
  		      &spi_##idx##_data,				       \
  		      &spi_##idx##z_config,				       \
  		      POST_KERNEL, CONFIG_SPI_INIT_PRIORITY,		       \
  		      &spi_nrfx_driver_api)
  
  #ifdef CONFIG_SPI_0_NRF_SPI
  SPI_NRFX_SPI_DEVICE(0);
  #endif
  
  #ifdef CONFIG_SPI_1_NRF_SPI
  SPI_NRFX_SPI_DEVICE(1);
  #endif
  
  #ifdef CONFIG_SPI_2_NRF_SPI
  SPI_NRFX_SPI_DEVICE(2);
  #endif
  