1 // SPDX-License-Identifier: GPL-2.0-only
11 #include <linux/spi/spi.h>
12 #include <linux/crc-ccitt.h>
37 	/* a NULL skb means we just want the SPI chip select line to raise */  in __nci_spi_send()
39 		t.tx_buf = skb->data;  in __nci_spi_send()
40 		t.len = skb->len;  in __nci_spi_send()
47 	t.delay.value = nspi->xfer_udelay;  in __nci_spi_send()
48 	t.delay.unit = SPI_DELAY_UNIT_USECS;  in __nci_spi_send()
49 	t.speed_hz = nspi->xfer_speed_hz;  in __nci_spi_send()
54 	return spi_sync(nspi->spi, &m);  in __nci_spi_send()
61 	unsigned int payload_len = skb->len;  in nci_spi_send()
66 	/* add the NCI SPI header to the start of the buffer */  in nci_spi_send()
69 	hdr[1] = nspi->acknowledge_mode;  in nci_spi_send()
73 	if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {  in nci_spi_send()
76 		crc = crc_ccitt(CRC_INIT, skb->data, skb->len);  in nci_spi_send()
82 		/* Trick SPI driver to raise chip select */  in nci_spi_send()
90 			ret = -ETIME;  in nci_spi_send()
96 	if (ret != 0 || nspi->acknowledge_mode == NCI_SPI_CRC_DISABLED)  in nci_spi_send()
99 	reinit_completion(&nspi->req_completion);  in nci_spi_send()
101 							&nspi->req_completion,  in nci_spi_send()
104 	if (completion_rc <= 0 || nspi->req_result == ACKNOWLEDGE_NACK)  in nci_spi_send()
105 		ret = -EIO;  in nci_spi_send()
114 /* ---- Interface to NCI SPI drivers ---- */
117  * nci_spi_allocate_spi - allocate a new nci spi
119  * @spi: SPI device
121  * @delay: delay between transactions in us
124 struct nci_spi *nci_spi_allocate_spi(struct spi_device *spi,  in nci_spi_allocate_spi()  argument
125 				     u8 acknowledge_mode, unsigned int delay,  in nci_spi_allocate_spi()  argument
130 	nspi = devm_kzalloc(&spi->dev, sizeof(struct nci_spi), GFP_KERNEL);  in nci_spi_allocate_spi()
134 	nspi->acknowledge_mode = acknowledge_mode;  in nci_spi_allocate_spi()
135 	nspi->xfer_udelay = delay;  in nci_spi_allocate_spi()
136 	/* Use controller max SPI speed by default */  in nci_spi_allocate_spi()
137 	nspi->xfer_speed_hz = 0;  in nci_spi_allocate_spi()
138 	nspi->spi = spi;  in nci_spi_allocate_spi()
139 	nspi->ndev = ndev;  in nci_spi_allocate_spi()
140 	init_completion(&nspi->req_completion);  in nci_spi_allocate_spi()
153 	skb = nci_skb_alloc(nspi->ndev, 0, GFP_KERNEL);  in send_acknowledge()
155 		return -ENOMEM;  in send_acknowledge()
157 	/* add the NCI SPI header to the start of the buffer */  in send_acknowledge()
164 	crc = crc_ccitt(CRC_INIT, skb->data, skb->len);  in send_acknowledge()
180 	struct spi_transfer tx, rx;  in __nci_spi_read()  local
186 	memset(&tx, 0, sizeof(struct spi_transfer));  in __nci_spi_read()
188 	req[1] = nspi->acknowledge_mode;  in __nci_spi_read()
189 	tx.tx_buf = req;  in __nci_spi_read()
190 	tx.len = 2;  in __nci_spi_read()
191 	tx.cs_change = 0;  in __nci_spi_read()
192 	tx.speed_hz = nspi->xfer_speed_hz;  in __nci_spi_read()
193 	spi_message_add_tail(&tx, &m);  in __nci_spi_read()
199 	rx.speed_hz = nspi->xfer_speed_hz;  in __nci_spi_read()
202 	ret = spi_sync(nspi->spi, &m);  in __nci_spi_read()
206 	if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)  in __nci_spi_read()
212 	skb = nci_skb_alloc(nspi->ndev, rx_len, GFP_KERNEL);  in __nci_spi_read()
222 	rx.delay.value = nspi->xfer_udelay;  in __nci_spi_read()
223 	rx.delay.unit = SPI_DELAY_UNIT_USECS;  in __nci_spi_read()
224 	rx.speed_hz = nspi->xfer_speed_hz;  in __nci_spi_read()
227 	ret = spi_sync(nspi->spi, &m);  in __nci_spi_read()
231 	if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {  in __nci_spi_read()
246 	u16 crc_data = (skb->data[skb->len - 2] << 8) |  in nci_spi_check_crc()
247 			skb->data[skb->len - 1];  in nci_spi_check_crc()
250 	ret = (crc_ccitt(CRC_INIT, skb->data, skb->len - NCI_SPI_CRC_LEN)  in nci_spi_check_crc()
253 	skb_trim(skb, skb->len - NCI_SPI_CRC_LEN);  in nci_spi_check_crc()
262 	ret = skb->data[0] >> NCI_SPI_ACK_SHIFT;  in nci_spi_get_ack()
271  * nci_spi_read - read frame from NCI SPI drivers
273  * @nspi: The nci spi
277  * is non-interruptible, and has no timeout.
285 	/* Retrieve frame from SPI */  in nci_spi_read()
290 	if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {  in nci_spi_read()
299 		nspi->req_result = nci_spi_get_ack(skb);  in nci_spi_read()
300 		if (nspi->req_result)  in nci_spi_read()
301 			complete(&nspi->req_completion);  in nci_spi_read()
307 	if (!skb->len) {  in nci_spi_read()
313 	if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)  in nci_spi_read()
322 MODULE_DESCRIPTION("NFC Controller Interface (NCI) SPI link layer");