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 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 
182 static 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 
191 module_spi_driver(cyttsp_spi_driver);
192 
193 MODULE_LICENSE("GPL");
194 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
195 MODULE_AUTHOR("Cypress");
196 MODULE_ALIAS("spi:cyttsp");
197