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
43static 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
128static 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
135static 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
142static 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
148static 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
173static int cyttsp_spi_remove(struct spi_device *spi)
174{
175	struct cyttsp *ts = spi_get_drvdata(spi);
176
177	cyttsp_remove(ts);
178
179	return 0;
180}
181
182static struct spi_driver cyttsp_spi_driver = {
183	.driver = {
184		.name	= CY_SPI_NAME,
185		.pm	= &cyttsp_pm_ops,
186	},
187	.probe  = cyttsp_spi_probe,
188	.remove = cyttsp_spi_remove,
189};
190
191module_spi_driver(cyttsp_spi_driver);
192
193MODULE_LICENSE("GPL");
194MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
195MODULE_AUTHOR("Cypress");
196MODULE_ALIAS("spi:cyttsp");
197