1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Source for:
4 * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
5 * For use with Cypress Txx3xx parts.
6 * Supported parts include:
7 * CY8CTST341
8 * CY8CTMA340
9 *
10 * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
11 * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
12 * Copyright (C) 2013 Cypress Semiconductor
13 *
14 * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com>
15 */
16
17#include "cyttsp_core.h"
18
19#include <linux/delay.h>
20#include <linux/input.h>
21#include <linux/spi/spi.h>
22
23#define CY_SPI_NAME		"cyttsp-spi"
24
25#define CY_SPI_WR_OP		0x00 /* r/~w */
26#define CY_SPI_RD_OP		0x01
27#define CY_SPI_CMD_BYTES	4
28#define CY_SPI_SYNC_BYTE	2
29#define CY_SPI_SYNC_ACK1	0x62 /* from protocol v.2 */
30#define CY_SPI_SYNC_ACK2	0x9D /* from protocol v.2 */
31#define CY_SPI_DATA_SIZE	128
32#define CY_SPI_DATA_BUF_SIZE	(CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
33#define CY_SPI_BITS_PER_WORD	8
34
35static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
36			   u8 op, u16 reg, u8 *buf, int length)
37{
38	struct spi_device *spi = to_spi_device(dev);
39	struct spi_message msg;
40	struct spi_transfer xfer[2];
41	u8 *wr_buf = &xfer_buf[0];
42	u8 *rd_buf = &xfer_buf[CY_SPI_DATA_BUF_SIZE];
43	int retval;
44	int i;
45
46	if (length > CY_SPI_DATA_SIZE) {
47		dev_err(dev, "%s: length %d is too big.\n",
48			__func__, length);
49		return -EINVAL;
50	}
51
52	memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE);
53	memset(rd_buf, 0, CY_SPI_DATA_BUF_SIZE);
54
55	wr_buf[0] = 0x00; /* header byte 0 */
56	wr_buf[1] = 0xFF; /* header byte 1 */
57	wr_buf[2] = reg;  /* reg index */
58	wr_buf[3] = op;   /* r/~w */
59	if (op == CY_SPI_WR_OP)
60		memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
61
62	memset(xfer, 0, sizeof(xfer));
63	spi_message_init(&msg);
64
65	/*
66	  We set both TX and RX buffers because Cypress TTSP
67	  requires full duplex operation.
68	*/
69	xfer[0].tx_buf = wr_buf;
70	xfer[0].rx_buf = rd_buf;
71	switch (op) {
72	case CY_SPI_WR_OP:
73		xfer[0].len = length + CY_SPI_CMD_BYTES;
74		spi_message_add_tail(&xfer[0], &msg);
75		break;
76
77	case CY_SPI_RD_OP:
78		xfer[0].len = CY_SPI_CMD_BYTES;
79		spi_message_add_tail(&xfer[0], &msg);
80
81		xfer[1].rx_buf = buf;
82		xfer[1].len = length;
83		spi_message_add_tail(&xfer[1], &msg);
84		break;
85
86	default:
87		dev_err(dev, "%s: bad operation code=%d\n", __func__, op);
88		return -EINVAL;
89	}
90
91	retval = spi_sync(spi, &msg);
92	if (retval < 0) {
93		dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n",
94			__func__, retval, xfer[1].len, op);
95
96		/*
97		 * do not return here since was a bad ACK sequence
98		 * let the following ACK check handle any errors and
99		 * allow silent retries
100		 */
101	}
102
103	if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK1 ||
104	    rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) {
105		dev_dbg(dev, "%s: operation %d failed\n", __func__, op);
106
107		for (i = 0; i < CY_SPI_CMD_BYTES; i++)
108			dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n",
109				__func__, i, rd_buf[i]);
110		for (i = 0; i < length; i++)
111			dev_dbg(dev, "%s: test buf[%d]:0x%02x\n",
112				__func__, i, buf[i]);
113
114		return -EIO;
115	}
116
117	return 0;
118}
119
120static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
121				      u16 addr, u8 length, void *data)
122{
123	return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
124			length);
125}
126
127static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
128				       u16 addr, u8 length, const void *data)
129{
130	return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
131			length);
132}
133
134static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = {
135	.bustype	= BUS_SPI,
136	.write		= cyttsp_spi_write_block_data,
137	.read		= cyttsp_spi_read_block_data,
138};
139
140static int cyttsp_spi_probe(struct spi_device *spi)
141{
142	struct cyttsp *ts;
143	int error;
144
145	/* Set up SPI*/
146	spi->bits_per_word = CY_SPI_BITS_PER_WORD;
147	spi->mode = SPI_MODE_0;
148	error = spi_setup(spi);
149	if (error < 0) {
150		dev_err(&spi->dev, "%s: SPI setup error %d\n",
151			__func__, error);
152		return error;
153	}
154
155	ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
156			  CY_SPI_DATA_BUF_SIZE * 2);
157	if (IS_ERR(ts))
158		return PTR_ERR(ts);
159
160	spi_set_drvdata(spi, ts);
161
162	return 0;
163}
164
165static const struct of_device_id cyttsp_of_spi_match[] = {
166	{ .compatible = "cypress,cy8ctma340", },
167	{ .compatible = "cypress,cy8ctst341", },
168	{ /* sentinel */ }
169};
170MODULE_DEVICE_TABLE(of, cyttsp_of_spi_match);
171
172static struct spi_driver cyttsp_spi_driver = {
173	.driver = {
174		.name	= CY_SPI_NAME,
175		.pm	= pm_sleep_ptr(&cyttsp_pm_ops),
176		.of_match_table = cyttsp_of_spi_match,
177	},
178	.probe  = cyttsp_spi_probe,
179};
180
181module_spi_driver(cyttsp_spi_driver);
182
183MODULE_LICENSE("GPL");
184MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
185MODULE_AUTHOR("Cypress");
186MODULE_ALIAS("spi:cyttsp");
187