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