drivers: spi_nrfx_spim: Change the way the nrfx driver is configured

According to the nRF5340 PS, for 32 Mbps high-speed SPI using SPIM4,
drive configuration H0H1 must be used. The underlying nrfx_spim driver
does it properly in its initialization function, so change the shim to
(re)initialize the driver when the SPI configuration is to be changed
(only then the speed to use is known), to avoid the need of duplicating
the corresponding code in the shim itself.

Signed-off-by: Andrzej Głąbek <[email protected]>

Author: anangl

drivers/spi/spi_nrfx_spim.c

@@ -19,20 +19,23 @@ LOG_MODULE_REGISTER(spi_nrfx_spim);
 struct spi_nrfx_data {
 	struct spi_context ctx;
 	const struct device *dev;
-	size_t chunk_len;
-	bool   busy;
+	size_t  chunk_len;
+	bool    busy;
+	bool    initialized;
 #if (CONFIG_SPI_NRFX_RAM_BUFFER_SIZE > 0)
-	uint8_t   buffer[CONFIG_SPI_NRFX_RAM_BUFFER_SIZE];
+	uint8_t buffer[CONFIG_SPI_NRFX_RAM_BUFFER_SIZE];
 #endif
 };
 
 struct spi_nrfx_config {
 	nrfx_spim_t	   spim;
 	size_t		   max_chunk_len;
 	uint32_t	   max_freq;
-	nrfx_spim_config_t config;
+	nrfx_spim_config_t def_config;
 };
 
+static void event_handler(const nrfx_spim_evt_t *p_event, void *p_context);
+
 static inline struct spi_nrfx_data *get_dev_data(const struct device *dev)
 {
 	return dev->data;
@@ -105,20 +108,20 @@ static inline nrf_spim_bit_order_t get_nrf_spim_bit_order(uint16_t operation)
 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 = &get_dev_data(dev)->ctx;
-	const nrfx_spim_t *spim = &dev_config->spim;
+	struct spi_context *ctx = &dev_data->ctx;
 	uint32_t max_freq = dev_config->max_freq;
-	nrf_spim_frequency_t spim_frequency;
+	nrfx_spim_config_t config;
+	nrfx_err_t result;
 
-	if (spi_context_configured(ctx, spi_cfg)) {
+	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);
+		LOG_ERR("Slave mode is not supported on %s", dev->name);
 		return -EINVAL;
 	}
 
@@ -133,8 +136,7 @@ static int configure(const struct device *dev,
 	}
 
 	if (SPI_WORD_SIZE_GET(spi_cfg->operation) != 8) {
-		LOG_ERR("Word sizes other than 8 bits"
-			    " are not supported");
+		LOG_ERR("Word sizes other than 8 bits are not supported");
 		return -EINVAL;
 	}
 
@@ -143,9 +145,6 @@ static int configure(const struct device *dev,
 		return -EINVAL;
 	}
 
-	ctx->config = spi_cfg;
-	spi_context_cs_configure(ctx);
-
 #if defined(CONFIG_SOC_NRF5340_CPUAPP)
 	/* On nRF5340, the 32 Mbps speed is supported by the application core
 	 * when it is running at 128 MHz (see the Timing specifications section
@@ -156,14 +155,31 @@ static int configure(const struct device *dev,
 		max_freq = 16000000;
 	}
 #endif
-	/* Limit the frequency to that supported by the SPIM instance */
-	spim_frequency = get_nrf_spim_frequency(MIN(spi_cfg->frequency,
-						    max_freq));
 
-	nrf_spim_configure(spim->p_reg,
-			   get_nrf_spim_mode(spi_cfg->operation),
-			   get_nrf_spim_bit_order(spi_cfg->operation));
-	nrf_spim_frequency_set(spim->p_reg, spim_frequency);
+	config = dev_config->def_config;
+
+	/* Limit the frequency to that supported by the SPIM instance. */
+	config.frequency = get_nrf_spim_frequency(MIN(spi_cfg->frequency,
+						      max_freq));
+	config.mode      = get_nrf_spim_mode(spi_cfg->operation);
+	config.bit_order = get_nrf_spim_bit_order(spi_cfg->operation);
+
+	if (dev_data->initialized) {
+		nrfx_spim_uninit(&dev_config->spim);
+		dev_data->initialized = false;
+	}
+
+	result = nrfx_spim_init(&dev_config->spim, &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;
 }
@@ -227,6 +243,18 @@ static void transfer_next_chunk(const struct device *dev)
 	dev_data->busy = false;
 }
 
+static void event_handler(const nrfx_spim_evt_t *p_event, void *p_context)
+{
+	struct spi_nrfx_data *dev_data = p_context;
+
+	if (p_event->type == NRFX_SPIM_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,
@@ -301,41 +329,6 @@ static const struct spi_driver_api spi_nrfx_driver_api = {
 	.release = spi_nrfx_release,
 };
 
-
-static void event_handler(const nrfx_spim_evt_t *p_event, void *p_context)
-{
-	struct spi_nrfx_data *dev_data = p_context;
-
-	if (p_event->type == NRFX_SPIM_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 init_spim(const struct device *dev)
-{
-	struct spi_nrfx_data *data = get_dev_data(dev);
-	nrfx_err_t result;
-
-	data->dev = dev;
-
-	/* This sets only default values of frequency, mode and bit order.
-	 * The proper ones are set in configure() when a transfer is started.
-	 */
-	result = nrfx_spim_init(&get_dev_config(dev)->spim,
-				&get_dev_config(dev)->config,
-				event_handler,
-				data);
-	if (result != NRFX_SUCCESS) {
-		LOG_ERR("Failed to initialize device: %s", dev->name);
-		return -EBUSY;
-	}
-
-	return 0;
-}
-
 #ifdef CONFIG_PM_DEVICE
 static int spim_nrfx_pm_control(const struct device *dev,
 				enum pm_device_action action)
@@ -346,13 +339,14 @@ static int spim_nrfx_pm_control(const struct device *dev,
 
 	switch (action) {
 	case PM_DEVICE_ACTION_RESUME:
-		ret = init_spim(dev);
-		/* Force reconfiguration before next transfer */
-		data->ctx.config = NULL;
+		/* No action needed at this point, nrfx_spim_init() will be
+		 * called at configuration before the next transfer.
+		 */
 		break;
 
 	case PM_DEVICE_ACTION_SUSPEND:
 		nrfx_spim_uninit(&config->spim);
+		data->initialized = false;
 		break;
 
 	default:
@@ -401,28 +395,25 @@ static int spim_nrfx_pm_control(const struct device *dev,
 		IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_SPIM##idx),		       \
 			    DT_IRQ(SPIM(idx), priority),		       \
 			    nrfx_isr, nrfx_spim_##idx##_irq_handler, 0);       \
-		int err = init_spim(dev);				       \
 		spi_context_unlock_unconditionally(&get_dev_data(dev)->ctx);   \
-		return err;						       \
+		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(SPIM(idx)),			       \
 		.busy = false,						       \
 	};								       \
 	static const struct spi_nrfx_config spi_##idx##z_config = {	       \
 		.spim = NRFX_SPIM_INSTANCE(idx),			       \
 		.max_chunk_len = (1 << SPIM##idx##_EASYDMA_MAXCNT_SIZE) - 1,   \
 		.max_freq = SPIM##idx##_MAX_DATARATE * 1000000,		       \
-		.config = {						       \
+		.def_config = {						       \
 			.sck_pin   = SPIM_PROP(idx, sck_pin),		       \
 			.mosi_pin  = SPIM_PROP(idx, mosi_pin),		       \
 			.miso_pin  = SPIM_PROP(idx, miso_pin),		       \
 			.ss_pin    = NRFX_SPIM_PIN_NOT_USED,		       \
 			.orc       = CONFIG_SPI_##idx##_NRF_ORC,	       \
-			.frequency = NRF_SPIM_FREQ_4M,			       \
-			.mode      = NRF_SPIM_MODE_0,			       \
-			.bit_order = NRF_SPIM_BIT_ORDER_MSB_FIRST,	       \
 			.miso_pull = SPIM_NRFX_MISO_PULL(idx),		       \
 			SPI_NRFX_SPIM_EXTENDED_CONFIG(idx)		       \
 		}							       \