1 /*
2 * Source for:
3 * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
4 * For use with Cypress Txx4xx parts.
5 * Supported parts include:
6 * TMA4XX
7 * TMA1036
8 *
9 * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
10 * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
11 * Copyright (C) 2013 Cypress Semiconductor
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * version 2, and only version 2, as published by the
16 * Free Software Foundation.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 *
23 * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com>
24 *
25 */
26
27 #include "cyttsp4_core.h"
28
29 #include <linux/delay.h>
30 #include <linux/input.h>
31 #include <linux/spi/spi.h>
32
33 #define CY_SPI_WR_OP 0x00 /* r/~w */
34 #define CY_SPI_RD_OP 0x01
35 #define CY_SPI_BITS_PER_WORD 8
36 #define CY_SPI_A8_BIT 0x02
37 #define CY_SPI_WR_HEADER_BYTES 2
38 #define CY_SPI_RD_HEADER_BYTES 1
39 #define CY_SPI_CMD_BYTES 2
40 #define CY_SPI_SYNC_BYTE 0
41 #define CY_SPI_SYNC_ACK 0x62 /* from TRM *A protocol */
42 #define CY_SPI_DATA_SIZE (2 * 256)
43
44 #define CY_SPI_DATA_BUF_SIZE (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
45
cyttsp_spi_xfer(struct device * dev,u8 * xfer_buf,u8 op,u16 reg,u8 * buf,int length)46 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
47 u8 op, u16 reg, u8 *buf, int length)
48 {
49 struct spi_device *spi = to_spi_device(dev);
50 struct spi_message msg;
51 struct spi_transfer xfer[2];
52 u8 *wr_buf = &xfer_buf[0];
53 u8 rd_buf[CY_SPI_CMD_BYTES];
54 int retval;
55 int i;
56
57 if (length > CY_SPI_DATA_SIZE) {
58 dev_err(dev, "%s: length %d is too big.\n",
59 __func__, length);
60 return -EINVAL;
61 }
62
63 memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE);
64 memset(rd_buf, 0, CY_SPI_CMD_BYTES);
65
66 wr_buf[0] = op + (((reg >> 8) & 0x1) ? CY_SPI_A8_BIT : 0);
67 if (op == CY_SPI_WR_OP) {
68 wr_buf[1] = reg & 0xFF;
69 if (length > 0)
70 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
71 }
72
73 memset(xfer, 0, sizeof(xfer));
74 spi_message_init(&msg);
75
76 /*
77 We set both TX and RX buffers because Cypress TTSP
78 requires full duplex operation.
79 */
80 xfer[0].tx_buf = wr_buf;
81 xfer[0].rx_buf = rd_buf;
82 switch (op) {
83 case CY_SPI_WR_OP:
84 xfer[0].len = length + CY_SPI_CMD_BYTES;
85 spi_message_add_tail(&xfer[0], &msg);
86 break;
87
88 case CY_SPI_RD_OP:
89 xfer[0].len = CY_SPI_RD_HEADER_BYTES;
90 spi_message_add_tail(&xfer[0], &msg);
91
92 xfer[1].rx_buf = buf;
93 xfer[1].len = length;
94 spi_message_add_tail(&xfer[1], &msg);
95 break;
96
97 default:
98 dev_err(dev, "%s: bad operation code=%d\n", __func__, op);
99 return -EINVAL;
100 }
101
102 retval = spi_sync(spi, &msg);
103 if (retval < 0) {
104 dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n",
105 __func__, retval, xfer[1].len, op);
106
107 /*
108 * do not return here since was a bad ACK sequence
109 * let the following ACK check handle any errors and
110 * allow silent retries
111 */
112 }
113
114 if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK) {
115 dev_dbg(dev, "%s: operation %d failed\n", __func__, op);
116
117 for (i = 0; i < CY_SPI_CMD_BYTES; i++)
118 dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n",
119 __func__, i, rd_buf[i]);
120 for (i = 0; i < length; i++)
121 dev_dbg(dev, "%s: test buf[%d]:0x%02x\n",
122 __func__, i, buf[i]);
123
124 return -EIO;
125 }
126
127 return 0;
128 }
129
cyttsp_spi_read_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,void * data)130 static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
131 u16 addr, u8 length, void *data)
132 {
133 int rc;
134
135 rc = cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, NULL, 0);
136 if (rc)
137 return rc;
138 else
139 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
140 length);
141 }
142
cyttsp_spi_write_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,const void * data)143 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
144 u16 addr, u8 length, const void *data)
145 {
146 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
147 length);
148 }
149
150 static const struct cyttsp4_bus_ops cyttsp_spi_bus_ops = {
151 .bustype = BUS_SPI,
152 .write = cyttsp_spi_write_block_data,
153 .read = cyttsp_spi_read_block_data,
154 };
155
cyttsp4_spi_probe(struct spi_device * spi)156 static int cyttsp4_spi_probe(struct spi_device *spi)
157 {
158 struct cyttsp4 *ts;
159 int error;
160
161 /* Set up SPI*/
162 spi->bits_per_word = CY_SPI_BITS_PER_WORD;
163 spi->mode = SPI_MODE_0;
164 error = spi_setup(spi);
165 if (error < 0) {
166 dev_err(&spi->dev, "%s: SPI setup error %d\n",
167 __func__, error);
168 return error;
169 }
170
171 ts = cyttsp4_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
172 CY_SPI_DATA_BUF_SIZE);
173
174 return PTR_ERR_OR_ZERO(ts);
175 }
176
cyttsp4_spi_remove(struct spi_device * spi)177 static int cyttsp4_spi_remove(struct spi_device *spi)
178 {
179 struct cyttsp4 *ts = spi_get_drvdata(spi);
180 cyttsp4_remove(ts);
181
182 return 0;
183 }
184
185 static struct spi_driver cyttsp4_spi_driver = {
186 .driver = {
187 .name = CYTTSP4_SPI_NAME,
188 .pm = &cyttsp4_pm_ops,
189 },
190 .probe = cyttsp4_spi_probe,
191 .remove = cyttsp4_spi_remove,
192 };
193
194 module_spi_driver(cyttsp4_spi_driver);
195
196 MODULE_LICENSE("GPL");
197 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
198 MODULE_AUTHOR("Cypress");
199 MODULE_ALIAS("spi:cyttsp4");
200