GNU Linux-libre 4.9.328-gnu1
[releases.git] / drivers / input / touchscreen / cyttsp_spi.c
1 /*
2  * Source for:
3  * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
4  * For use with Cypress Txx3xx parts.
5  * Supported parts include:
6  * CY8CTST341
7  * CY8CTMA340
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 "cyttsp_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_CMD_BYTES        4
36 #define CY_SPI_SYNC_BYTE        2
37 #define CY_SPI_SYNC_ACK1        0x62 /* from protocol v.2 */
38 #define CY_SPI_SYNC_ACK2        0x9D /* from protocol v.2 */
39 #define CY_SPI_DATA_SIZE        128
40 #define CY_SPI_DATA_BUF_SIZE    (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
41 #define CY_SPI_BITS_PER_WORD    8
42
43 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
44                            u8 op, u16 reg, u8 *buf, int length)
45 {
46         struct spi_device *spi = to_spi_device(dev);
47         struct spi_message msg;
48         struct spi_transfer xfer[2];
49         u8 *wr_buf = &xfer_buf[0];
50         u8 *rd_buf = &xfer_buf[CY_SPI_DATA_BUF_SIZE];
51         int retval;
52         int i;
53
54         if (length > CY_SPI_DATA_SIZE) {
55                 dev_err(dev, "%s: length %d is too big.\n",
56                         __func__, length);
57                 return -EINVAL;
58         }
59
60         memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE);
61         memset(rd_buf, 0, CY_SPI_DATA_BUF_SIZE);
62
63         wr_buf[0] = 0x00; /* header byte 0 */
64         wr_buf[1] = 0xFF; /* header byte 1 */
65         wr_buf[2] = reg;  /* reg index */
66         wr_buf[3] = op;   /* r/~w */
67         if (op == CY_SPI_WR_OP)
68                 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
69
70         memset(xfer, 0, sizeof(xfer));
71         spi_message_init(&msg);
72
73         /*
74           We set both TX and RX buffers because Cypress TTSP
75           requires full duplex operation.
76         */
77         xfer[0].tx_buf = wr_buf;
78         xfer[0].rx_buf = rd_buf;
79         switch (op) {
80         case CY_SPI_WR_OP:
81                 xfer[0].len = length + CY_SPI_CMD_BYTES;
82                 spi_message_add_tail(&xfer[0], &msg);
83                 break;
84
85         case CY_SPI_RD_OP:
86                 xfer[0].len = CY_SPI_CMD_BYTES;
87                 spi_message_add_tail(&xfer[0], &msg);
88
89                 xfer[1].rx_buf = buf;
90                 xfer[1].len = length;
91                 spi_message_add_tail(&xfer[1], &msg);
92                 break;
93
94         default:
95                 dev_err(dev, "%s: bad operation code=%d\n", __func__, op);
96                 return -EINVAL;
97         }
98
99         retval = spi_sync(spi, &msg);
100         if (retval < 0) {
101                 dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n",
102                         __func__, retval, xfer[1].len, op);
103
104                 /*
105                  * do not return here since was a bad ACK sequence
106                  * let the following ACK check handle any errors and
107                  * allow silent retries
108                  */
109         }
110
111         if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK1 ||
112             rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) {
113                 dev_dbg(dev, "%s: operation %d failed\n", __func__, op);
114
115                 for (i = 0; i < CY_SPI_CMD_BYTES; i++)
116                         dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n",
117                                 __func__, i, rd_buf[i]);
118                 for (i = 0; i < length; i++)
119                         dev_dbg(dev, "%s: test buf[%d]:0x%02x\n",
120                                 __func__, i, buf[i]);
121
122                 return -EIO;
123         }
124
125         return 0;
126 }
127
128 static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
129                                       u16 addr, u8 length, void *data)
130 {
131         return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
132                         length);
133 }
134
135 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
136                                        u16 addr, u8 length, const void *data)
137 {
138         return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
139                         length);
140 }
141
142 static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = {
143         .bustype        = BUS_SPI,
144         .write          = cyttsp_spi_write_block_data,
145         .read           = cyttsp_spi_read_block_data,
146 };
147
148 static int cyttsp_spi_probe(struct spi_device *spi)
149 {
150         struct cyttsp *ts;
151         int error;
152
153         /* Set up SPI*/
154         spi->bits_per_word = CY_SPI_BITS_PER_WORD;
155         spi->mode = SPI_MODE_0;
156         error = spi_setup(spi);
157         if (error < 0) {
158                 dev_err(&spi->dev, "%s: SPI setup error %d\n",
159                         __func__, error);
160                 return error;
161         }
162
163         ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
164                           CY_SPI_DATA_BUF_SIZE * 2);
165         if (IS_ERR(ts))
166                 return PTR_ERR(ts);
167
168         spi_set_drvdata(spi, ts);
169
170         return 0;
171 }
172
173 static struct spi_driver cyttsp_spi_driver = {
174         .driver = {
175                 .name   = CY_SPI_NAME,
176                 .pm     = &cyttsp_pm_ops,
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");