1 // SPDX-License-Identifier: GPL-2.0
5  * Driver for KEBA SPI host controller type 2 FPGA IP core
10 #include <linux/spi/spi.h>
42 #define KSPI2_SPEED_HZ_MIN(kspi)	(kspi->base_speed_hz / 65536)
43 #define KSPI2_SPEED_HZ_MAX(kspi)	(kspi->base_speed_hz / 2)
57 	u32 base_speed_hz; /* SPI base clock frequency in HZ */
70 	 * The SPI controller has an IN_USE bit for locking access to the  in kspi2_inuse_lock()
71 	 * controller. This enables the use of the SPI controller by other none  in kspi2_inuse_lock()
74 	 * If the SPI controller is free, then the first read returns  in kspi2_inuse_lock()
75 	 * IN_USE == 0. After that the SPI controller is locked and further  in kspi2_inuse_lock()
78 	 * The SPI controller is unlocked by writing 1 into IN_USE.  in kspi2_inuse_lock()
80 	 * The IN_USE bit acts as a hardware semaphore for the SPI controller.  in kspi2_inuse_lock()
83 	ret = readb_poll_timeout(kspi->base + KSPI2_STATUS_REG,  in kspi2_inuse_lock()
87 		dev_warn(&kspi->auxdev->auxdev.dev, "%s err!\n", __func__);  in kspi2_inuse_lock()
94 	/* unlock the controller by writing 1 into IN_USE */  in kspi2_inuse_unlock()
95 	iowrite8(KSPI2_STATUS_IN_USE, kspi->base + KSPI2_STATUS_REG);  in kspi2_inuse_unlock()
102 	/* lock hardware semaphore before actual use of controller */  in kspi2_prepare_hardware()
110 	/* unlock hardware semaphore after actual use of controller */  in kspi2_unprepare_hardware()
125 		if ((kspi->base_speed_hz >> (div + 1)) <= max_speed_hz)  in kspi2_calc_minimal_divider()
136 	if (val != (kspi->control_shadow & mask)) {  in kspi2_write_control_reg()
137 		kspi->control_shadow = (kspi->control_shadow & ~mask) | val;  in kspi2_write_control_reg()
138 		iowrite8(kspi->control_shadow, kspi->base + KSPI2_CONTROL_REG);  in kspi2_write_control_reg()
148 	iowrite8(tx, kspi->base + KSPI2_DATA_REG);  in kspi2_txrx_byte()
151 	ret = readb_poll_timeout(kspi->base + KSPI2_STATUS_REG,  in kspi2_txrx_byte()
159 		*rx = ioread8(kspi->base + KSPI2_DATA_REG);  in kspi2_txrx_byte()
171 	for (i = 0; i < t->len; i++) {  in kspi2_process_transfer()
172 		if (t->tx_buf)  in kspi2_process_transfer()
173 			tx = ((const u8 *)t->tx_buf)[i];  in kspi2_process_transfer()
179 		if (t->rx_buf)  in kspi2_process_transfer()
180 			((u8 *)t->rx_buf)[i] = rx;  in kspi2_process_transfer()
187 				 struct spi_device *spi,  in kspi2_setup_transfer()  argument
190 	u32 max_speed_hz = spi->max_speed_hz;  in kspi2_setup_transfer()
194 	 * spi_device (spi) has default parameters. Some of these can be  in kspi2_setup_transfer()
197 	if (t->bits_per_word && ((t->bits_per_word % 8) != 0)) {  in kspi2_setup_transfer()
198 		dev_err(&spi->dev, "Word width %d not supported!\n",  in kspi2_setup_transfer()
199 			t->bits_per_word);  in kspi2_setup_transfer()
201 		return -EINVAL;  in kspi2_setup_transfer()
204 	if (t->speed_hz && (t->speed_hz < max_speed_hz))  in kspi2_setup_transfer()
205 		max_speed_hz = t->speed_hz;  in kspi2_setup_transfer()
214 			      struct spi_device *spi,  in kspi2_transfer_one()  argument
220 	ret = kspi2_setup_transfer(kspi, spi, t);  in kspi2_transfer_one()
224 	if (t->len) {  in kspi2_transfer_one()
233 static void kspi2_set_cs(struct spi_device *spi, bool enable)  in kspi2_set_cs()  argument
235 	struct spi_controller *host = spi->controller;  in kspi2_set_cs()
238 	/* controller is using active low chip select signals by design */  in kspi2_set_cs()
240 		iowrite8(spi_get_chipselect(spi, 0), kspi->base + KSPI2_CS_NR_REG);  in kspi2_set_cs()
242 		iowrite8(KSPI2_CS_NR_NONE, kspi->base + KSPI2_CS_NR_REG);  in kspi2_set_cs()
249 	struct spi_device *spi = msg->spi;  in kspi2_prepare_message()  local
252 	/* setup SPI clock phase and polarity */  in kspi2_prepare_message()
253 	if (spi->mode & SPI_CPHA)  in kspi2_prepare_message()
255 	if (spi->mode & SPI_CPOL)  in kspi2_prepare_message()
262 static int kspi2_setup(struct spi_device *spi)  in kspi2_setup()  argument
264 	struct kspi2 *kspi = spi_controller_get_devdata(spi->controller);  in kspi2_setup()
268 	 * and directly before the SPI transfer starts.  in kspi2_setup()
271 	if (spi->mode & ~KSPI2_MODE_BITS) {  in kspi2_setup()
272 		dev_err(&spi->dev, "Mode %d not supported!\n", spi->mode);  in kspi2_setup()
274 		return -EINVAL;  in kspi2_setup()
277 	if ((spi->bits_per_word % 8) != 0) {  in kspi2_setup()
278 		dev_err(&spi->dev, "Word width %d not supported!\n",  in kspi2_setup()
279 			spi->bits_per_word);  in kspi2_setup()
281 		return -EINVAL;  in kspi2_setup()
284 	if ((spi->max_speed_hz == 0) ||  in kspi2_setup()
285 	    (spi->max_speed_hz > KSPI2_SPEED_HZ_MAX(kspi)))  in kspi2_setup()
286 		spi->max_speed_hz = KSPI2_SPEED_HZ_MAX(kspi);  in kspi2_setup()
288 	if (spi->max_speed_hz < KSPI2_SPEED_HZ_MIN(kspi)) {  in kspi2_setup()
289 		dev_err(&spi->dev, "Requested speed of %d Hz is too low!\n",  in kspi2_setup()
290 			spi->max_speed_hz);  in kspi2_setup()
292 		return -EINVAL;  in kspi2_setup()
302 	for (i = 0; i < kspi->device_size; i++) {  in kspi2_unregister_devices()
303 		struct spi_device *device = kspi->device[i];  in kspi2_unregister_devices()
312 	struct spi_board_info *info = kspi->auxdev->info;  in kspi2_register_devices()
315 	/* register all known SPI devices */  in kspi2_register_devices()
316 	for (i = 0; i < kspi->auxdev->info_size; i++) {  in kspi2_register_devices()
317 		struct spi_device *device = spi_new_device(kspi->host, &info[i]);  in kspi2_register_devices()
322 			return -ENODEV;  in kspi2_register_devices()
324 		kspi->device[i] = device;  in kspi2_register_devices()
332 	iowrite8(KSPI2_CONTROL_INIT, kspi->base + KSPI2_CONTROL_REG);  in kspi2_init()
333 	kspi->control_shadow = KSPI2_CONTROL_INIT;  in kspi2_init()
335 	iowrite8(KSPI2_CS_NR_NONE, kspi->base + KSPI2_CS_NR_REG);  in kspi2_init()
341 	struct device *dev = &auxdev->dev;  in kspi2_probe()
349 		return -ENOMEM;  in kspi2_probe()
351 	kspi->auxdev = container_of(auxdev, struct keba_spi_auxdev, auxdev);  in kspi2_probe()
352 	kspi->host = host;  in kspi2_probe()
353 	kspi->device = devm_kcalloc(dev, kspi->auxdev->info_size,  in kspi2_probe()
354 				    sizeof(*kspi->device), GFP_KERNEL);  in kspi2_probe()
355 	if (!kspi->device)  in kspi2_probe()
356 		return -ENOMEM;  in kspi2_probe()
357 	kspi->device_size = kspi->auxdev->info_size;  in kspi2_probe()
360 	kspi->base = devm_ioremap_resource(dev, &kspi->auxdev->io);  in kspi2_probe()
361 	if (IS_ERR(kspi->base))  in kspi2_probe()
362 		return PTR_ERR(kspi->base);  in kspi2_probe()
364 	/* read the SPI base clock frequency */  in kspi2_probe()
365 	clk_reg = ioread8(kspi->base + KSPI2_CLK_FREQ_REG);  in kspi2_probe()
368 		kspi->base_speed_hz = 62500000; break;  in kspi2_probe()
370 		kspi->base_speed_hz = 33333333; break;  in kspi2_probe()
372 		kspi->base_speed_hz = 125000000; break;  in kspi2_probe()
374 		kspi->base_speed_hz = 50000000; break;  in kspi2_probe()
376 		kspi->base_speed_hz = 100000000; break;  in kspi2_probe()
378 		dev_err(dev, "Undefined SPI base clock frequency!\n");  in kspi2_probe()
379 		return -ENODEV;  in kspi2_probe()
384 	host->bus_num = -1;  in kspi2_probe()
385 	host->num_chipselect = KSPI2_NUM_CS;  in kspi2_probe()
386 	host->mode_bits = KSPI2_MODE_BITS;  in kspi2_probe()
387 	host->setup = kspi2_setup;  in kspi2_probe()
388 	host->prepare_transfer_hardware = kspi2_prepare_hardware;  in kspi2_probe()
389 	host->unprepare_transfer_hardware = kspi2_unprepare_hardware;  in kspi2_probe()
390 	host->prepare_message = kspi2_prepare_message;  in kspi2_probe()
391 	host->set_cs = kspi2_set_cs;  in kspi2_probe()
392 	host->transfer_one = kspi2_transfer_one;  in kspi2_probe()
416 	{ .name = "keba.spi" },
430 MODULE_DESCRIPTION("KEBA SPI host controller driver");