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
cyttsp_spi_xfer(struct device * dev,u8 * xfer_buf,u8 op,u16 reg,u8 * buf,int length)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
cyttsp_spi_read_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,void * data)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
cyttsp_spi_write_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,const void * data)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
cyttsp_spi_probe(struct spi_device * spi)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