1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * Cadence SPI controller driver (master mode only)
5  * Copyright (C) 2008 - 2014 Xilinx, Inc.
7  * based on Blackfin On-Chip SPI Driver (spi_bfin5xx.c)
20 #include <linux/spi/spi.h>
23 #define CDNS_SPI_NAME		"cdns-spi"
40  * SPI Configuration Register bit Masks
43  * of the SPI controller
61  * SPI Configuration Register - Baud rate and slave select
75  * SPI Interrupt Registers bit Masks
80 #define CDNS_SPI_IXR_TXOW	0x00000004 /* SPI TX FIFO Overwater */
81 #define CDNS_SPI_IXR_MODF	0x00000002 /* SPI Mode Fault */
82 #define CDNS_SPI_IXR_RXNEMTY 0x00000010 /* SPI RX FIFO Not Empty */
85 #define CDNS_SPI_IXR_TXFULL	0x00000008 /* SPI TX Full */
86 #define CDNS_SPI_IXR_ALL	0x0000007F /* SPI all interrupts */
89  * SPI Enable Register bit Masks
91  * This register is used to enable or disable the SPI controller
93 #define CDNS_SPI_ER_ENABLE	0x00000001 /* SPI Enable Bit Mask */
94 #define CDNS_SPI_ER_DISABLE	0x0 /* SPI Disable Bit Mask */
100  * struct cdns_spi - This definition defines spi driver instance
101  * @regs:		Virtual address of the SPI controller registers
104  * @speed_hz:		Current SPI bus clock speed in Hz
128 /* Macros for the SPI controller read/write */
131 	return readl_relaxed(xspi->regs + offset);  in cdns_spi_read()
136 	writel_relaxed(val, xspi->regs + offset);  in cdns_spi_write()
140  * cdns_spi_init_hw - Initialize the hardware and configure the SPI controller
143  * On reset the SPI controller is configured to be in master mode, baud rate
146  * This function initializes the SPI controller to disable and clear all the
148  * chip select lines, and enable the SPI controller.
154 	if (xspi->is_decoded_cs)  in cdns_spi_init_hw()
170  * cdns_spi_chipselect - Select or deselect the chip select line
171  * @spi:	Pointer to the spi_device structure
174 static void cdns_spi_chipselect(struct spi_device *spi, bool is_high)  in cdns_spi_chipselect()  argument
176 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);  in cdns_spi_chipselect()
187 		if (!(xspi->is_decoded_cs))  in cdns_spi_chipselect()
188 			ctrl_reg |= ((~(CDNS_SPI_SS0 << spi->chip_select)) <<  in cdns_spi_chipselect()
192 			ctrl_reg |= (spi->chip_select << CDNS_SPI_SS_SHIFT) &  in cdns_spi_chipselect()
200  * cdns_spi_config_clock_mode - Sets clock polarity and phase
201  * @spi:	Pointer to the spi_device structure
205 static void cdns_spi_config_clock_mode(struct spi_device *spi)  in cdns_spi_config_clock_mode()  argument
207 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);  in cdns_spi_config_clock_mode()
213 	/* Set the SPI clock phase and clock polarity */  in cdns_spi_config_clock_mode()
215 	if (spi->mode & SPI_CPHA)  in cdns_spi_config_clock_mode()
217 	if (spi->mode & SPI_CPOL)  in cdns_spi_config_clock_mode()
224 		 * polarity as it will cause the SPI slave to see spurious clock  in cdns_spi_config_clock_mode()
234  * cdns_spi_config_clock_freq - Sets clock frequency
235  * @spi:	Pointer to the spi_device structure
243  * the requested frequency is higher or lower than that is supported by the SPI
247 static void cdns_spi_config_clock_freq(struct spi_device *spi,  in cdns_spi_config_clock_freq()  argument
250 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);  in cdns_spi_config_clock_freq()
254 	frequency = xspi->clk_rate;  in cdns_spi_config_clock_freq()
259 	if (xspi->speed_hz != transfer->speed_hz) {  in cdns_spi_config_clock_freq()
263 		       (frequency / (2 << baud_rate_val)) > transfer->speed_hz)  in cdns_spi_config_clock_freq()
269 		xspi->speed_hz = frequency / (2 << baud_rate_val);  in cdns_spi_config_clock_freq()
275  * cdns_spi_setup_transfer - Configure SPI controller for specified transfer
276  * @spi:	Pointer to the spi_device structure
280  * Sets the operational mode of SPI controller for the next SPI transfer and
285 static int cdns_spi_setup_transfer(struct spi_device *spi,  in cdns_spi_setup_transfer()  argument
288 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);  in cdns_spi_setup_transfer()
290 	cdns_spi_config_clock_freq(spi, transfer);  in cdns_spi_setup_transfer()
292 	dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u clock speed\n",  in cdns_spi_setup_transfer()
293 		__func__, spi->mode, spi->bits_per_word,  in cdns_spi_setup_transfer()
294 		xspi->speed_hz);  in cdns_spi_setup_transfer()
300  * cdns_spi_fill_tx_fifo - Fills the TX FIFO with as many bytes as possible
307 	while ((trans_cnt < xspi->tx_fifo_depth) &&  in cdns_spi_fill_tx_fifo()
308 	       (xspi->tx_bytes > 0)) {  in cdns_spi_fill_tx_fifo()
311 		 * then spi control did't work thoroughly, add one byte delay  in cdns_spi_fill_tx_fifo()
317 		if (xspi->txbuf)  in cdns_spi_fill_tx_fifo()
318 			cdns_spi_write(xspi, CDNS_SPI_TXD, *xspi->txbuf++);  in cdns_spi_fill_tx_fifo()
322 		xspi->tx_bytes--;  in cdns_spi_fill_tx_fifo()
328  * cdns_spi_irq - Interrupt service routine of the SPI controller
336  * the SPI subsystem will identify the error as the remaining bytes to be
337  * transferred is non-zero.
353 		/* Indicate that transfer is completed, the SPI subsystem will  in cdns_spi_irq()
355 		 * transferred is non-zero  in cdns_spi_irq()
363 		trans_cnt = xspi->rx_bytes - xspi->tx_bytes;  in cdns_spi_irq()
370 			if (xspi->rxbuf)  in cdns_spi_irq()
371 				*xspi->rxbuf++ = data;  in cdns_spi_irq()
373 			xspi->rx_bytes--;  in cdns_spi_irq()
374 			trans_cnt--;  in cdns_spi_irq()
377 		if (xspi->tx_bytes) {  in cdns_spi_irq()
395 	cdns_spi_config_clock_mode(msg->spi);  in cdns_prepare_message()
400  * cdns_transfer_one - Initiates the SPI transfer
402  * @spi:	Pointer to the spi_device structure
406  * This function fills the TX FIFO, starts the SPI transfer and
412 			     struct spi_device *spi,  in cdns_transfer_one()  argument
417 	xspi->txbuf = transfer->tx_buf;  in cdns_transfer_one()
418 	xspi->rxbuf = transfer->rx_buf;  in cdns_transfer_one()
419 	xspi->tx_bytes = transfer->len;  in cdns_transfer_one()
420 	xspi->rx_bytes = transfer->len;  in cdns_transfer_one()
422 	cdns_spi_setup_transfer(spi, transfer);  in cdns_transfer_one()
427 	return transfer->len;  in cdns_transfer_one()
431  * cdns_prepare_transfer_hardware - Prepares hardware for transfer.
435  * This function enables SPI master controller.
449  * cdns_unprepare_transfer_hardware - Relaxes hardware after transfer
453  * This function disables the SPI master controller when no slave selected.
462 	/* Disable the SPI if slave is deselected */  in cdns_unprepare_transfer_hardware()
472  * cdns_spi_detect_fifo_depth - Detect the FIFO depth of the hardware
475  * The depth of the TX FIFO is a synthesis configuration parameter of the SPI
477  * FIFO size - 1. This is used to detect the size of the FIFO.
483 	xspi->tx_fifo_depth = cdns_spi_read(xspi, CDNS_SPI_THLD) + 1;  in cdns_spi_detect_fifo_depth()
490  * cdns_spi_probe - Probe method for the SPI driver
504 	master = spi_alloc_master(&pdev->dev, sizeof(*xspi));  in cdns_spi_probe()
506 		return -ENOMEM;  in cdns_spi_probe()
509 	master->dev.of_node = pdev->dev.of_node;  in cdns_spi_probe()
512 	xspi->regs = devm_platform_ioremap_resource(pdev, 0);  in cdns_spi_probe()
513 	if (IS_ERR(xspi->regs)) {  in cdns_spi_probe()
514 		ret = PTR_ERR(xspi->regs);  in cdns_spi_probe()
518 	xspi->pclk = devm_clk_get(&pdev->dev, "pclk");  in cdns_spi_probe()
519 	if (IS_ERR(xspi->pclk)) {  in cdns_spi_probe()
520 		dev_err(&pdev->dev, "pclk clock not found.\n");  in cdns_spi_probe()
521 		ret = PTR_ERR(xspi->pclk);  in cdns_spi_probe()
525 	xspi->ref_clk = devm_clk_get(&pdev->dev, "ref_clk");  in cdns_spi_probe()
526 	if (IS_ERR(xspi->ref_clk)) {  in cdns_spi_probe()
527 		dev_err(&pdev->dev, "ref_clk clock not found.\n");  in cdns_spi_probe()
528 		ret = PTR_ERR(xspi->ref_clk);  in cdns_spi_probe()
532 	ret = clk_prepare_enable(xspi->pclk);  in cdns_spi_probe()
534 		dev_err(&pdev->dev, "Unable to enable APB clock.\n");  in cdns_spi_probe()
538 	ret = clk_prepare_enable(xspi->ref_clk);  in cdns_spi_probe()
540 		dev_err(&pdev->dev, "Unable to enable device clock.\n");  in cdns_spi_probe()
544 	pm_runtime_use_autosuspend(&pdev->dev);  in cdns_spi_probe()
545 	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);  in cdns_spi_probe()
546 	pm_runtime_get_noresume(&pdev->dev);  in cdns_spi_probe()
547 	pm_runtime_set_active(&pdev->dev);  in cdns_spi_probe()
548 	pm_runtime_enable(&pdev->dev);  in cdns_spi_probe()
550 	ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);  in cdns_spi_probe()
552 		master->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS;  in cdns_spi_probe()
554 		master->num_chipselect = num_cs;  in cdns_spi_probe()
556 	ret = of_property_read_u32(pdev->dev.of_node, "is-decoded-cs",  in cdns_spi_probe()
557 				   &xspi->is_decoded_cs);  in cdns_spi_probe()
559 		xspi->is_decoded_cs = 0;  in cdns_spi_probe()
563 	/* SPI controller initializations */  in cdns_spi_probe()
568 		ret = -ENXIO;  in cdns_spi_probe()
572 	ret = devm_request_irq(&pdev->dev, irq, cdns_spi_irq,  in cdns_spi_probe()
573 			       0, pdev->name, master);  in cdns_spi_probe()
575 		ret = -ENXIO;  in cdns_spi_probe()
576 		dev_err(&pdev->dev, "request_irq failed\n");  in cdns_spi_probe()
580 	master->use_gpio_descriptors = true;  in cdns_spi_probe()
581 	master->prepare_transfer_hardware = cdns_prepare_transfer_hardware;  in cdns_spi_probe()
582 	master->prepare_message = cdns_prepare_message;  in cdns_spi_probe()
583 	master->transfer_one = cdns_transfer_one;  in cdns_spi_probe()
584 	master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;  in cdns_spi_probe()
585 	master->set_cs = cdns_spi_chipselect;  in cdns_spi_probe()
586 	master->auto_runtime_pm = true;  in cdns_spi_probe()
587 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;  in cdns_spi_probe()
589 	xspi->clk_rate = clk_get_rate(xspi->ref_clk);  in cdns_spi_probe()
591 	master->max_speed_hz = xspi->clk_rate / 4;  in cdns_spi_probe()
592 	xspi->speed_hz = master->max_speed_hz;  in cdns_spi_probe()
594 	master->bits_per_word_mask = SPI_BPW_MASK(8);  in cdns_spi_probe()
596 	pm_runtime_mark_last_busy(&pdev->dev);  in cdns_spi_probe()
597 	pm_runtime_put_autosuspend(&pdev->dev);  in cdns_spi_probe()
601 		dev_err(&pdev->dev, "spi_register_master failed\n");  in cdns_spi_probe()
608 	pm_runtime_set_suspended(&pdev->dev);  in cdns_spi_probe()
609 	pm_runtime_disable(&pdev->dev);  in cdns_spi_probe()
610 	clk_disable_unprepare(xspi->ref_clk);  in cdns_spi_probe()
612 	clk_disable_unprepare(xspi->pclk);  in cdns_spi_probe()
619  * cdns_spi_remove - Remove method for the SPI driver
635 	clk_disable_unprepare(xspi->ref_clk);  in cdns_spi_remove()
636 	clk_disable_unprepare(xspi->pclk);  in cdns_spi_remove()
637 	pm_runtime_set_suspended(&pdev->dev);  in cdns_spi_remove()
638 	pm_runtime_disable(&pdev->dev);  in cdns_spi_remove()
646  * cdns_spi_suspend - Suspend method for the SPI driver
649  * This function disables the SPI controller and
662  * cdns_spi_resume - Resume method for the SPI driver
679  * cdns_spi_runtime_resume - Runtime resume method for the SPI driver
692 	ret = clk_prepare_enable(xspi->pclk);  in cdns_spi_runtime_resume()
698 	ret = clk_prepare_enable(xspi->ref_clk);  in cdns_spi_runtime_resume()
701 		clk_disable_unprepare(xspi->pclk);  in cdns_spi_runtime_resume()
708  * cdns_spi_runtime_suspend - Runtime suspend method for the SPI driver
720 	clk_disable_unprepare(xspi->ref_clk);  in cdns_spi_runtime_suspend()
721 	clk_disable_unprepare(xspi->pclk);  in cdns_spi_runtime_suspend()
733 	{ .compatible = "xlnx,zynq-spi-r1p6" },
734 	{ .compatible = "cdns,spi-r1p6" },
739 /* cdns_spi_driver - This structure defines the SPI subsystem platform driver */
753 MODULE_DESCRIPTION("Cadence SPI driver");