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
cyttsp_spi_xfer(struct device * dev,u8 * xfer_buf,u8 op,u16 reg,u8 * buf,int length)35 static 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
cyttsp_spi_read_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,void * data)120 static 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
cyttsp_spi_write_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,const void * data)127 static 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
134 static 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
cyttsp_spi_probe(struct spi_device * spi)140 static 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
165 static const struct of_device_id cyttsp_of_spi_match[] = {
166 { .compatible = "cypress,cy8ctma340", },
167 { .compatible = "cypress,cy8ctst341", },
168 { /* sentinel */ }
169 };
170 MODULE_DEVICE_TABLE(of, cyttsp_of_spi_match);
171
172 static 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
181 module_spi_driver(cyttsp_spi_driver);
182
183 MODULE_LICENSE("GPL");
184 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
185 MODULE_AUTHOR("Cypress");
186 MODULE_ALIAS("spi:cyttsp");
187