2  * Cadence SPI controller driver (master mode only)
4  * Copyright (C) 2008 - 2014 Xilinx, Inc.
6  * based on Blackfin On-Chip SPI Driver (spi_bfin5xx.c)
24 #include <linux/spi/spi.h>
27 #define CDNS_SPI_NAME		"cdns-spi"
44  * SPI Configuration Register bit Masks
47  * of the SPI controller
65  * SPI Configuration Register - Baud rate and slave select
78  * SPI Interrupt Registers bit Masks
83 #define CDNS_SPI_IXR_TXOW	0x00000004 /* SPI TX FIFO Overwater */
84 #define CDNS_SPI_IXR_MODF	0x00000002 /* SPI Mode Fault */
85 #define CDNS_SPI_IXR_RXNEMTY 0x00000010 /* SPI RX FIFO Not Empty */
88 #define CDNS_SPI_IXR_TXFULL	0x00000008 /* SPI TX Full */
89 #define CDNS_SPI_IXR_ALL	0x0000007F /* SPI all interrupts */
92  * SPI Enable Register bit Masks
94  * This register is used to enable or disable the SPI controller
96 #define CDNS_SPI_ER_ENABLE	0x00000001 /* SPI Enable Bit Mask */
97 #define CDNS_SPI_ER_DISABLE	0x0 /* SPI Disable Bit Mask */
99 /* SPI FIFO depth in bytes */
106  * struct cdns_spi - This definition defines spi driver instance
107  * @regs:		Virtual address of the SPI controller registers
110  * @speed_hz:		Current SPI bus clock speed in Hz
135 /* Macros for the SPI controller read/write */
138 	return readl_relaxed(xspi->regs + offset);  in cdns_spi_read()
143 	writel_relaxed(val, xspi->regs + offset);  in cdns_spi_write()
147  * cdns_spi_init_hw - Initialize the hardware and configure the SPI controller
150  * On reset the SPI controller is configured to be in master mode, baud rate
153  * This function initializes the SPI controller to disable and clear all the
155  * chip select lines, and enable the SPI controller.
161 	if (xspi->is_decoded_cs)  in cdns_spi_init_hw()
177  * cdns_spi_chipselect - Select or deselect the chip select line
178  * @spi:	Pointer to the spi_device structure
181 static void cdns_spi_chipselect(struct spi_device *spi, bool is_high)  in cdns_spi_chipselect()  argument
183 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);  in cdns_spi_chipselect()
194 		if (!(xspi->is_decoded_cs))  in cdns_spi_chipselect()
195 			ctrl_reg |= ((~(CDNS_SPI_SS0 << spi->chip_select)) <<  in cdns_spi_chipselect()
199 			ctrl_reg |= (spi->chip_select << CDNS_SPI_SS_SHIFT) &  in cdns_spi_chipselect()
207  * cdns_spi_config_clock_mode - Sets clock polarity and phase
208  * @spi:	Pointer to the spi_device structure
212 static void cdns_spi_config_clock_mode(struct spi_device *spi)  in cdns_spi_config_clock_mode()  argument
214 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);  in cdns_spi_config_clock_mode()
220 	/* Set the SPI clock phase and clock polarity */  in cdns_spi_config_clock_mode()
222 	if (spi->mode & SPI_CPHA)  in cdns_spi_config_clock_mode()
224 	if (spi->mode & SPI_CPOL)  in cdns_spi_config_clock_mode()
231 		 * polarity as it will cause the SPI slave to see spurious clock  in cdns_spi_config_clock_mode()
241  * cdns_spi_config_clock_freq - Sets clock frequency
242  * @spi:	Pointer to the spi_device structure
250  * the requested frequency is higher or lower than that is supported by the SPI
251  * controller the driver will set the highest or lowest frequency supported by
252  * controller.
254 static void cdns_spi_config_clock_freq(struct spi_device *spi,  in cdns_spi_config_clock_freq()  argument
257 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);  in cdns_spi_config_clock_freq()
261 	frequency = clk_get_rate(xspi->ref_clk);  in cdns_spi_config_clock_freq()
266 	if (xspi->speed_hz != transfer->speed_hz) {  in cdns_spi_config_clock_freq()
270 		       (frequency / (2 << baud_rate_val)) > transfer->speed_hz)  in cdns_spi_config_clock_freq()
276 		xspi->speed_hz = frequency / (2 << baud_rate_val);  in cdns_spi_config_clock_freq()
282  * cdns_spi_setup_transfer - Configure SPI controller for specified transfer
283  * @spi:	Pointer to the spi_device structure
287  * Sets the operational mode of SPI controller for the next SPI transfer and
292 static int cdns_spi_setup_transfer(struct spi_device *spi,  in cdns_spi_setup_transfer()  argument
295 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);  in cdns_spi_setup_transfer()
297 	cdns_spi_config_clock_freq(spi, transfer);  in cdns_spi_setup_transfer()
299 	dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u clock speed\n",  in cdns_spi_setup_transfer()
300 		__func__, spi->mode, spi->bits_per_word,  in cdns_spi_setup_transfer()
301 		xspi->speed_hz);  in cdns_spi_setup_transfer()
307  * cdns_spi_fill_tx_fifo - Fills the TX FIFO with as many bytes as possible
315 	       (xspi->tx_bytes > 0)) {  in cdns_spi_fill_tx_fifo()
318 		 * then spi control did't work thoroughly, add one byte delay  in cdns_spi_fill_tx_fifo()
324 		if (xspi->txbuf)  in cdns_spi_fill_tx_fifo()
325 			cdns_spi_write(xspi, CDNS_SPI_TXD, *xspi->txbuf++);  in cdns_spi_fill_tx_fifo()
329 		xspi->tx_bytes--;  in cdns_spi_fill_tx_fifo()
335  * cdns_spi_irq - Interrupt service routine of the SPI controller
343  * the SPI subsystem will identify the error as the remaining bytes to be
344  * transferred is non-zero.
359 		/* Indicate that transfer is completed, the SPI subsystem will  in cdns_spi_irq()
361 		 * transferred is non-zero  in cdns_spi_irq()
369 		trans_cnt = xspi->rx_bytes - xspi->tx_bytes;  in cdns_spi_irq()
376 			if (xspi->rxbuf)  in cdns_spi_irq()
377 				*xspi->rxbuf++ = data;  in cdns_spi_irq()
379 			xspi->rx_bytes--;  in cdns_spi_irq()
380 			trans_cnt--;  in cdns_spi_irq()
383 		if (xspi->tx_bytes) {  in cdns_spi_irq()
401 	cdns_spi_config_clock_mode(msg->spi);  in cdns_prepare_message()
406  * cdns_transfer_one - Initiates the SPI transfer
408  * @spi:	Pointer to the spi_device structure
412  * This function fills the TX FIFO, starts the SPI transfer and
418 			     struct spi_device *spi,  in cdns_transfer_one()  argument
423 	xspi->txbuf = transfer->tx_buf;  in cdns_transfer_one()
424 	xspi->rxbuf = transfer->rx_buf;  in cdns_transfer_one()
425 	xspi->tx_bytes = transfer->len;  in cdns_transfer_one()
426 	xspi->rx_bytes = transfer->len;  in cdns_transfer_one()
428 	cdns_spi_setup_transfer(spi, transfer);  in cdns_transfer_one()
433 	return transfer->len;  in cdns_transfer_one()
437  * cdns_prepare_transfer_hardware - Prepares hardware for transfer.
439  *		information about the controller.
441  * This function enables SPI master controller.
455  * cdns_unprepare_transfer_hardware - Relaxes hardware after transfer
457  *		information about the controller.
459  * This function disables the SPI master controller.
472 static int cdns_spi_setup(struct spi_device *spi)  in cdns_spi_setup()  argument
475 	int ret = -EINVAL;  in cdns_spi_setup()
476 	struct cdns_spi_device_data *cdns_spi_data = spi_get_ctldata(spi);  in cdns_spi_setup()
478 	/* this is a pin managed by the controller, leave it alone */  in cdns_spi_setup()
479 	if (spi->cs_gpio == -ENOENT)  in cdns_spi_setup()
486 			return -ENOMEM;  in cdns_spi_setup()
487 		cdns_spi_data->gpio_requested = false;  in cdns_spi_setup()
488 		spi_set_ctldata(spi, cdns_spi_data);  in cdns_spi_setup()
492 	if (!cdns_spi_data->gpio_requested && gpio_is_valid(spi->cs_gpio)) {  in cdns_spi_setup()
493 		ret = gpio_request_one(spi->cs_gpio,  in cdns_spi_setup()
494 				       (spi->mode & SPI_CS_HIGH) ?  in cdns_spi_setup()
496 				       dev_name(&spi->dev));  in cdns_spi_setup()
498 			dev_err(&spi->dev, "can't request chipselect gpio %d\n",  in cdns_spi_setup()
499 				spi->cs_gpio);  in cdns_spi_setup()
501 			cdns_spi_data->gpio_requested = true;  in cdns_spi_setup()
503 		if (gpio_is_valid(spi->cs_gpio)) {  in cdns_spi_setup()
504 			int mode = ((spi->mode & SPI_CS_HIGH) ?  in cdns_spi_setup()
507 			ret = gpio_direction_output(spi->cs_gpio, mode);  in cdns_spi_setup()
509 				dev_err(&spi->dev, "chipselect gpio %d setup failed (%d)\n",  in cdns_spi_setup()
510 					spi->cs_gpio, ret);  in cdns_spi_setup()
517 static void cdns_spi_cleanup(struct spi_device *spi)  in cdns_spi_cleanup()  argument
519 	struct cdns_spi_device_data *cdns_spi_data = spi_get_ctldata(spi);  in cdns_spi_cleanup()
522 		if (cdns_spi_data->gpio_requested)  in cdns_spi_cleanup()
523 			gpio_free(spi->cs_gpio);  in cdns_spi_cleanup()
525 		spi_set_ctldata(spi, NULL);  in cdns_spi_cleanup()
531  * cdns_spi_probe - Probe method for the SPI driver
546 	master = spi_alloc_master(&pdev->dev, sizeof(*xspi));  in cdns_spi_probe()
548 		return -ENOMEM;  in cdns_spi_probe()
551 	master->dev.of_node = pdev->dev.of_node;  in cdns_spi_probe()
555 	xspi->regs = devm_ioremap_resource(&pdev->dev, res);  in cdns_spi_probe()
556 	if (IS_ERR(xspi->regs)) {  in cdns_spi_probe()
557 		ret = PTR_ERR(xspi->regs);  in cdns_spi_probe()
561 	xspi->pclk = devm_clk_get(&pdev->dev, "pclk");  in cdns_spi_probe()
562 	if (IS_ERR(xspi->pclk)) {  in cdns_spi_probe()
563 		dev_err(&pdev->dev, "pclk clock not found.\n");  in cdns_spi_probe()
564 		ret = PTR_ERR(xspi->pclk);  in cdns_spi_probe()
568 	xspi->ref_clk = devm_clk_get(&pdev->dev, "ref_clk");  in cdns_spi_probe()
569 	if (IS_ERR(xspi->ref_clk)) {  in cdns_spi_probe()
570 		dev_err(&pdev->dev, "ref_clk clock not found.\n");  in cdns_spi_probe()
571 		ret = PTR_ERR(xspi->ref_clk);  in cdns_spi_probe()
575 	ret = clk_prepare_enable(xspi->pclk);  in cdns_spi_probe()
577 		dev_err(&pdev->dev, "Unable to enable APB clock.\n");  in cdns_spi_probe()
581 	ret = clk_prepare_enable(xspi->ref_clk);  in cdns_spi_probe()
583 		dev_err(&pdev->dev, "Unable to enable device clock.\n");  in cdns_spi_probe()
587 	ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);  in cdns_spi_probe()
589 		master->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS;  in cdns_spi_probe()
591 		master->num_chipselect = num_cs;  in cdns_spi_probe()
593 	ret = of_property_read_u32(pdev->dev.of_node, "is-decoded-cs",  in cdns_spi_probe()
594 				   &xspi->is_decoded_cs);  in cdns_spi_probe()
596 		xspi->is_decoded_cs = 0;  in cdns_spi_probe()
598 	/* SPI controller initializations */  in cdns_spi_probe()
601 	pm_runtime_set_active(&pdev->dev);  in cdns_spi_probe()
602 	pm_runtime_enable(&pdev->dev);  in cdns_spi_probe()
603 	pm_runtime_use_autosuspend(&pdev->dev);  in cdns_spi_probe()
604 	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);  in cdns_spi_probe()
608 		ret = -ENXIO;  in cdns_spi_probe()
609 		dev_err(&pdev->dev, "irq number is invalid\n");  in cdns_spi_probe()
613 	ret = devm_request_irq(&pdev->dev, irq, cdns_spi_irq,  in cdns_spi_probe()
614 			       0, pdev->name, master);  in cdns_spi_probe()
616 		ret = -ENXIO;  in cdns_spi_probe()
617 		dev_err(&pdev->dev, "request_irq failed\n");  in cdns_spi_probe()
621 	master->prepare_transfer_hardware = cdns_prepare_transfer_hardware;  in cdns_spi_probe()
622 	master->prepare_message = cdns_prepare_message;  in cdns_spi_probe()
623 	master->transfer_one = cdns_transfer_one;  in cdns_spi_probe()
624 	master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;  in cdns_spi_probe()
625 	master->set_cs = cdns_spi_chipselect;  in cdns_spi_probe()
626 	master->setup = cdns_spi_setup;  in cdns_spi_probe()
627 	master->cleanup = cdns_spi_cleanup;  in cdns_spi_probe()
628 	master->auto_runtime_pm = true;  in cdns_spi_probe()
629 	master->mode_bits = SPI_CPOL | SPI_CPHA;  in cdns_spi_probe()
632 	master->max_speed_hz = clk_get_rate(xspi->ref_clk) / 4;  in cdns_spi_probe()
633 	xspi->speed_hz = master->max_speed_hz;  in cdns_spi_probe()
635 	master->bits_per_word_mask = SPI_BPW_MASK(8);  in cdns_spi_probe()
639 		dev_err(&pdev->dev, "spi_register_master failed\n");  in cdns_spi_probe()
646 	pm_runtime_set_suspended(&pdev->dev);  in cdns_spi_probe()
647 	pm_runtime_disable(&pdev->dev);  in cdns_spi_probe()
648 	clk_disable_unprepare(xspi->ref_clk);  in cdns_spi_probe()
650 	clk_disable_unprepare(xspi->pclk);  in cdns_spi_probe()
657  * cdns_spi_remove - Remove method for the SPI driver
673 	clk_disable_unprepare(xspi->ref_clk);  in cdns_spi_remove()
674 	clk_disable_unprepare(xspi->pclk);  in cdns_spi_remove()
675 	pm_runtime_set_suspended(&pdev->dev);  in cdns_spi_remove()
676 	pm_runtime_disable(&pdev->dev);  in cdns_spi_remove()
684  * cdns_spi_suspend - Suspend method for the SPI driver
687  * This function disables the SPI controller and
700  * cdns_spi_resume - Resume method for the SPI driver
717  * cdns_spi_runtime_resume - Runtime resume method for the SPI driver
730 	ret = clk_prepare_enable(xspi->pclk);  in cnds_runtime_resume()
736 	ret = clk_prepare_enable(xspi->ref_clk);  in cnds_runtime_resume()
739 		clk_disable_unprepare(xspi->pclk);  in cnds_runtime_resume()
746  * cdns_spi_runtime_suspend - Runtime suspend method for the SPI driver
758 	clk_disable_unprepare(xspi->ref_clk);  in cnds_runtime_suspend()
759 	clk_disable_unprepare(xspi->pclk);  in cnds_runtime_suspend()
771 	{ .compatible = "xlnx,zynq-spi-r1p6" },
772 	{ .compatible = "cdns,spi-r1p6" },
777 /* cdns_spi_driver - This structure defines the SPI subsystem platform driver */
791 MODULE_DESCRIPTION("Cadence SPI driver");