1 // SPDX-License-Identifier: GPL-2.0
3 // Driver for AT91 USART Controllers as SPI
9 #include <linux/clk.h>
12 #include <linux/dma-direction.h>
22 #include <linux/spi/spi.h>
70 	readl_relaxed((port)->regs + US_##reg)
72 	writel_relaxed((value), (port)->regs + US_##reg)
75 	readb_relaxed((port)->regs + US_##reg)
77 	writeb_relaxed((value), (port)->regs + US_##reg)
84 	struct clk		*clk;  member
110 	aus->current_rx_remaining_bytes = 0;  in dma_callback()
111 	complete(&aus->xfer_completion);  in dma_callback()
115 				   struct spi_device *spi,  in at91_usart_spi_can_dma()  argument
120 	return aus->use_dma && xfer->len >= US_DMA_MIN_BYTES;  in at91_usart_spi_can_dma()
127 	struct device *dev = &aus->mpdev->dev;  in at91_usart_spi_configure_dma()
128 	phys_addr_t phybase = aus->phybase;  in at91_usart_spi_configure_dma()
135 	ctlr->dma_tx = dma_request_chan(dev, "tx");  in at91_usart_spi_configure_dma()
136 	if (IS_ERR_OR_NULL(ctlr->dma_tx)) {  in at91_usart_spi_configure_dma()
137 		if (IS_ERR(ctlr->dma_tx)) {  in at91_usart_spi_configure_dma()
138 			err = PTR_ERR(ctlr->dma_tx);  in at91_usart_spi_configure_dma()
143 			"DMA TX channel not available, SPI unable to use DMA\n");  in at91_usart_spi_configure_dma()
144 		err = -EBUSY;  in at91_usart_spi_configure_dma()
148 	ctlr->dma_rx = dma_request_chan(dev, "rx");  in at91_usart_spi_configure_dma()
149 	if (IS_ERR_OR_NULL(ctlr->dma_rx)) {  in at91_usart_spi_configure_dma()
150 		if (IS_ERR(ctlr->dma_rx)) {  in at91_usart_spi_configure_dma()
151 			err = PTR_ERR(ctlr->dma_rx);  in at91_usart_spi_configure_dma()
156 			"DMA RX channel not available, SPI unable to use DMA\n");  in at91_usart_spi_configure_dma()
157 		err = -EBUSY;  in at91_usart_spi_configure_dma()
170 	if (dmaengine_slave_config(ctlr->dma_rx, &slave_config)) {  in at91_usart_spi_configure_dma()
171 		dev_err(&ctlr->dev,  in at91_usart_spi_configure_dma()
173 		err = -EINVAL;  in at91_usart_spi_configure_dma()
178 	if (dmaengine_slave_config(ctlr->dma_tx, &slave_config)) {  in at91_usart_spi_configure_dma()
179 		dev_err(&ctlr->dev,  in at91_usart_spi_configure_dma()
181 		err = -EINVAL;  in at91_usart_spi_configure_dma()
185 	aus->use_dma = true;  in at91_usart_spi_configure_dma()
189 	if (!IS_ERR_OR_NULL(ctlr->dma_tx))  in at91_usart_spi_configure_dma()
190 		dma_release_channel(ctlr->dma_tx);  in at91_usart_spi_configure_dma()
191 	if (!IS_ERR_OR_NULL(ctlr->dma_rx))  in at91_usart_spi_configure_dma()
192 		dma_release_channel(ctlr->dma_rx);  in at91_usart_spi_configure_dma()
193 	ctlr->dma_tx = NULL;  in at91_usart_spi_configure_dma()
194 	ctlr->dma_rx = NULL;  in at91_usart_spi_configure_dma()
202 	if (ctlr->dma_rx)  in at91_usart_spi_release_dma()
203 		dma_release_channel(ctlr->dma_rx);  in at91_usart_spi_release_dma()
204 	if (ctlr->dma_tx)  in at91_usart_spi_release_dma()
205 		dma_release_channel(ctlr->dma_tx);  in at91_usart_spi_release_dma()
210 	if (ctlr->dma_rx)  in at91_usart_spi_stop_dma()
211 		dmaengine_terminate_all(ctlr->dma_rx);  in at91_usart_spi_stop_dma()
212 	if (ctlr->dma_tx)  in at91_usart_spi_stop_dma()
213 		dmaengine_terminate_all(ctlr->dma_tx);  in at91_usart_spi_stop_dma()
220 	struct dma_chan	 *rxchan = ctlr->dma_rx;  in at91_usart_spi_dma_transfer()
221 	struct dma_chan *txchan = ctlr->dma_tx;  in at91_usart_spi_dma_transfer()
230 					 xfer->rx_sg.sgl,  in at91_usart_spi_dma_transfer()
231 					 xfer->rx_sg.nents,  in at91_usart_spi_dma_transfer()
239 					 xfer->tx_sg.sgl,  in at91_usart_spi_dma_transfer()
240 					 xfer->tx_sg.nents,  in at91_usart_spi_dma_transfer()
247 	rxdesc->callback = dma_callback;  in at91_usart_spi_dma_transfer()
248 	rxdesc->callback_param = ctlr;  in at91_usart_spi_dma_transfer()
250 	cookie = rxdesc->tx_submit(rxdesc);  in at91_usart_spi_dma_transfer()
254 	cookie = txdesc->tx_submit(txdesc);  in at91_usart_spi_dma_transfer()
258 	rxchan->device->device_issue_pending(rxchan);  in at91_usart_spi_dma_transfer()
259 	txchan->device->device_issue_pending(txchan);  in at91_usart_spi_dma_transfer()
268 	return -ENOMEM;  in at91_usart_spi_dma_transfer()
273 	return wait_for_completion_timeout(&aus->xfer_completion,  in at91_usart_spi_dma_timeout()
279 	return aus->status & US_IR_TXRDY;  in at91_usart_spi_tx_ready()
284 	return aus->status & US_IR_RXRDY;  in at91_usart_spi_rx_ready()
289 	return aus->status & US_IR_OVRE;  in at91_usart_spi_check_overrun()
294 	aus->status = at91_usart_spi_readl(aus, CSR);  in at91_usart_spi_read_status()
295 	return aus->status;  in at91_usart_spi_read_status()
300 	unsigned int len = aus->current_transfer->len;  in at91_usart_spi_tx()
301 	unsigned int remaining = aus->current_tx_remaining_bytes;  in at91_usart_spi_tx()
302 	const u8  *tx_buf = aus->current_transfer->tx_buf;  in at91_usart_spi_tx()
308 		at91_usart_spi_writeb(aus, THR, tx_buf[len - remaining]);  in at91_usart_spi_tx()
309 		aus->current_tx_remaining_bytes--;  in at91_usart_spi_tx()
315 	int len = aus->current_transfer->len;  in at91_usart_spi_rx()
316 	int remaining = aus->current_rx_remaining_bytes;  in at91_usart_spi_rx()
317 	u8  *rx_buf = aus->current_transfer->rx_buf;  in at91_usart_spi_rx()
322 	rx_buf[len - remaining] = at91_usart_spi_readb(aus, RHR);  in at91_usart_spi_rx()
323 	aus->current_rx_remaining_bytes--;  in at91_usart_spi_rx()
331 			      DIV_ROUND_UP(aus->spi_clk, xfer->speed_hz));  in at91_usart_spi_set_xfer_speed()
339 	spin_lock(&aus->lock);  in at91_usart_spi_interrupt()
343 		aus->xfer_failed = true;  in at91_usart_spi_interrupt()
345 		spin_unlock(&aus->lock);  in at91_usart_spi_interrupt()
351 		spin_unlock(&aus->lock);  in at91_usart_spi_interrupt()
355 	spin_unlock(&aus->lock);  in at91_usart_spi_interrupt()
360 static int at91_usart_spi_setup(struct spi_device *spi)  in at91_usart_spi_setup()  argument
362 	struct at91_usart_spi *aus = spi_master_get_devdata(spi->controller);  in at91_usart_spi_setup()
363 	u32 *ausd = spi->controller_state;  in at91_usart_spi_setup()
366 	if (spi->mode & SPI_CPOL)  in at91_usart_spi_setup()
371 	if (spi->mode & SPI_CPHA)  in at91_usart_spi_setup()
376 	if (spi->mode & SPI_LOOP)  in at91_usart_spi_setup()
384 			return -ENOMEM;  in at91_usart_spi_setup()
386 		spi->controller_state = ausd;  in at91_usart_spi_setup()
391 	dev_dbg(&spi->dev,  in at91_usart_spi_setup()
392 		"setup: bpw %u mode 0x%x -> mr %d %08x\n",  in at91_usart_spi_setup()
393 		spi->bits_per_word, spi->mode, spi->chip_select, mr);  in at91_usart_spi_setup()
399 				       struct spi_device *spi,  in at91_usart_spi_transfer_one()  argument
407 	aus->xfer_failed = false;  in at91_usart_spi_transfer_one()
408 	aus->current_transfer = xfer;  in at91_usart_spi_transfer_one()
409 	aus->current_tx_remaining_bytes = xfer->len;  in at91_usart_spi_transfer_one()
410 	aus->current_rx_remaining_bytes = xfer->len;  in at91_usart_spi_transfer_one()
412 	while ((aus->current_tx_remaining_bytes ||  in at91_usart_spi_transfer_one()
413 		aus->current_rx_remaining_bytes) && !aus->xfer_failed) {  in at91_usart_spi_transfer_one()
414 		reinit_completion(&aus->xfer_completion);  in at91_usart_spi_transfer_one()
415 		if (at91_usart_spi_can_dma(ctlr, spi, xfer) &&  in at91_usart_spi_transfer_one()
424 				dev_err(&spi->dev, "DMA transfer timeout\n");  in at91_usart_spi_transfer_one()
425 				return -EIO;  in at91_usart_spi_transfer_one()
427 			aus->current_tx_remaining_bytes = 0;  in at91_usart_spi_transfer_one()
436 	if (aus->xfer_failed) {  in at91_usart_spi_transfer_one()
437 		dev_err(aus->dev, "Overrun!\n");  in at91_usart_spi_transfer_one()
438 		return -EIO;  in at91_usart_spi_transfer_one()
448 	struct spi_device *spi = message->spi;  in at91_usart_spi_prepare_message()  local
449 	u32 *ausd = spi->controller_state;  in at91_usart_spi_prepare_message()
469 static void at91_usart_spi_cleanup(struct spi_device *spi)  in at91_usart_spi_cleanup()  argument
471 	struct at91_usart_spi_device *ausd = spi->controller_state;  in at91_usart_spi_cleanup()
473 	spi->controller_state = NULL;  in at91_usart_spi_cleanup()
487 	cs_gpios = devm_gpiod_get_array_optional(&pdev->dev, "cs", GPIOD_OUT_LOW);  in at91_usart_gpio_setup()
500 	struct clk *clk;  in at91_usart_spi_probe()  local
504 	regs = platform_get_resource(to_platform_device(pdev->dev.parent),  in at91_usart_spi_probe()
507 		return -EINVAL;  in at91_usart_spi_probe()
509 	irq = platform_get_irq(to_platform_device(pdev->dev.parent), 0);  in at91_usart_spi_probe()
513 	clk = devm_clk_get(pdev->dev.parent, "usart");  in at91_usart_spi_probe()
514 	if (IS_ERR(clk))  in at91_usart_spi_probe()
515 		return PTR_ERR(clk);  in at91_usart_spi_probe()
517 	ret = -ENOMEM;  in at91_usart_spi_probe()
518 	controller = spi_alloc_master(&pdev->dev, sizeof(*aus));  in at91_usart_spi_probe()
526 	controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_CS_HIGH;  in at91_usart_spi_probe()
527 	controller->dev.of_node = pdev->dev.parent->of_node;  in at91_usart_spi_probe()
528 	controller->bits_per_word_mask = SPI_BPW_MASK(8);  in at91_usart_spi_probe()
529 	controller->setup = at91_usart_spi_setup;  in at91_usart_spi_probe()
530 	controller->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;  in at91_usart_spi_probe()
531 	controller->transfer_one = at91_usart_spi_transfer_one;  in at91_usart_spi_probe()
532 	controller->prepare_message = at91_usart_spi_prepare_message;  in at91_usart_spi_probe()
533 	controller->unprepare_message = at91_usart_spi_unprepare_message;  in at91_usart_spi_probe()
534 	controller->can_dma = at91_usart_spi_can_dma;  in at91_usart_spi_probe()
535 	controller->cleanup = at91_usart_spi_cleanup;  in at91_usart_spi_probe()
536 	controller->max_speed_hz = DIV_ROUND_UP(clk_get_rate(clk),  in at91_usart_spi_probe()
538 	controller->min_speed_hz = DIV_ROUND_UP(clk_get_rate(clk),  in at91_usart_spi_probe()
544 	aus->dev = &pdev->dev;  in at91_usart_spi_probe()
545 	aus->regs = devm_ioremap_resource(&pdev->dev, regs);  in at91_usart_spi_probe()
546 	if (IS_ERR(aus->regs)) {  in at91_usart_spi_probe()
547 		ret = PTR_ERR(aus->regs);  in at91_usart_spi_probe()
551 	aus->irq = irq;  in at91_usart_spi_probe()
552 	aus->clk = clk;  in at91_usart_spi_probe()
554 	ret = devm_request_irq(&pdev->dev, irq, at91_usart_spi_interrupt, 0,  in at91_usart_spi_probe()
555 			       dev_name(&pdev->dev), controller);  in at91_usart_spi_probe()
559 	ret = clk_prepare_enable(clk);  in at91_usart_spi_probe()
563 	aus->spi_clk = clk_get_rate(clk);  in at91_usart_spi_probe()
566 	aus->phybase = regs->start;  in at91_usart_spi_probe()
568 	aus->mpdev = to_platform_device(pdev->dev.parent);  in at91_usart_spi_probe()
574 	spin_lock_init(&aus->lock);  in at91_usart_spi_probe()
575 	init_completion(&aus->xfer_completion);  in at91_usart_spi_probe()
577 	ret = devm_spi_register_master(&pdev->dev, controller);  in at91_usart_spi_probe()
581 	dev_info(&pdev->dev,  in at91_usart_spi_probe()
582 		 "AT91 USART SPI Controller version 0x%x at %pa (irq %d)\n",  in at91_usart_spi_probe()
584 		 &regs->start, irq);  in at91_usart_spi_probe()
591 	clk_disable_unprepare(clk);  in at91_usart_spi_probe()
602 	clk_disable_unprepare(aus->clk);  in at91_usart_spi_runtime_suspend()
615 	return clk_prepare_enable(aus->clk);  in at91_usart_spi_runtime_resume()
656 	clk_disable_unprepare(aus->clk);  in at91_usart_spi_remove()
678 MODULE_DESCRIPTION("Microchip AT91 USART SPI Controller driver");