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 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * version 2, and only version 2, as published by the
15 * Free Software Foundation.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20 * GNU General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License along
23 * with this program; if not, write to the Free Software Foundation, Inc.,
24 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25 *
26 * Contact Cypress Semiconductor at www.cypress.com <kev@cypress.com>
27 *
28 */
29
30#include "cyttsp_core.h"
31
32#include <linux/delay.h>
33#include <linux/input.h>
34#include <linux/spi/spi.h>
35
36#define CY_SPI_WR_OP		0x00 /* r/~w */
37#define CY_SPI_RD_OP		0x01
38#define CY_SPI_CMD_BYTES	4
39#define CY_SPI_SYNC_BYTE	2
40#define CY_SPI_SYNC_ACK1	0x62 /* from protocol v.2 */
41#define CY_SPI_SYNC_ACK2	0x9D /* from protocol v.2 */
42#define CY_SPI_DATA_SIZE	128
43#define CY_SPI_DATA_BUF_SIZE	(CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
44#define CY_SPI_BITS_PER_WORD	8
45
46static int cyttsp_spi_xfer(struct cyttsp *ts,
47			   u8 op, u8 reg, u8 *buf, int length)
48{
49	struct spi_device *spi = to_spi_device(ts->dev);
50	struct spi_message msg;
51	struct spi_transfer xfer[2];
52	u8 *wr_buf = &ts->xfer_buf[0];
53	u8 *rd_buf = &ts->xfer_buf[CY_SPI_DATA_BUF_SIZE];
54	int retval;
55	int i;
56
57	if (length > CY_SPI_DATA_SIZE) {
58		dev_err(ts->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_DATA_BUF_SIZE);
65
66	wr_buf[0] = 0x00; /* header byte 0 */
67	wr_buf[1] = 0xFF; /* header byte 1 */
68	wr_buf[2] = reg;  /* reg index */
69	wr_buf[3] = op;   /* r/~w */
70	if (op == CY_SPI_WR_OP)
71		memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
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_CMD_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(ts->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(ts->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_ACK1 ||
115	    rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) {
116
117		dev_dbg(ts->dev, "%s: operation %d failed\n", __func__, op);
118
119		for (i = 0; i < CY_SPI_CMD_BYTES; i++)
120			dev_dbg(ts->dev, "%s: test rd_buf[%d]:0x%02x\n",
121				__func__, i, rd_buf[i]);
122		for (i = 0; i < length; i++)
123			dev_dbg(ts->dev, "%s: test buf[%d]:0x%02x\n",
124				__func__, i, buf[i]);
125
126		return -EIO;
127	}
128
129	return 0;
130}
131
132static int cyttsp_spi_read_block_data(struct cyttsp *ts,
133				      u8 addr, u8 length, void *data)
134{
135	return cyttsp_spi_xfer(ts, CY_SPI_RD_OP, addr, data, length);
136}
137
138static int cyttsp_spi_write_block_data(struct cyttsp *ts,
139				       u8 addr, u8 length, const void *data)
140{
141	return cyttsp_spi_xfer(ts, CY_SPI_WR_OP, addr, (void *)data, length);
142}
143
144static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = {
145	.bustype	= BUS_SPI,
146	.write		= cyttsp_spi_write_block_data,
147	.read		= cyttsp_spi_read_block_data,
148};
149
150static int __devinit cyttsp_spi_probe(struct spi_device *spi)
151{
152	struct cyttsp *ts;
153	int error;
154
155	/* Set up SPI*/
156	spi->bits_per_word = CY_SPI_BITS_PER_WORD;
157	spi->mode = SPI_MODE_0;
158	error = spi_setup(spi);
159	if (error < 0) {
160		dev_err(&spi->dev, "%s: SPI setup error %d\n",
161			__func__, error);
162		return error;
163	}
164
165	ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
166			  CY_SPI_DATA_BUF_SIZE * 2);
167	if (IS_ERR(ts))
168		return PTR_ERR(ts);
169
170	spi_set_drvdata(spi, ts);
171
172	return 0;
173}
174
175static int __devexit cyttsp_spi_remove(struct spi_device *spi)
176{
177	struct cyttsp *ts = spi_get_drvdata(spi);
178
179	cyttsp_remove(ts);
180
181	return 0;
182}
183
184static struct spi_driver cyttsp_spi_driver = {
185	.driver = {
186		.name	= CY_SPI_NAME,
187		.owner	= THIS_MODULE,
188		.pm	= &cyttsp_pm_ops,
189	},
190	.probe  = cyttsp_spi_probe,
191	.remove = __devexit_p(cyttsp_spi_remove),
192};
193
194module_spi_driver(cyttsp_spi_driver);
195
196MODULE_ALIAS("spi:cyttsp");
197MODULE_LICENSE("GPL");
198MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
199MODULE_AUTHOR("Cypress");
200MODULE_ALIAS("spi:cyttsp");
201