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 
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 
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 
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 
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 	if (IS_ERR(ts))
175 		return PTR_ERR(ts);
176 
177 	return 0;
178 }
179 
180 static int cyttsp4_spi_remove(struct spi_device *spi)
181 {
182 	struct cyttsp4 *ts = spi_get_drvdata(spi);
183 	cyttsp4_remove(ts);
184 
185 	return 0;
186 }
187 
188 static struct spi_driver cyttsp4_spi_driver = {
189 	.driver = {
190 		.name	= CYTTSP4_SPI_NAME,
191 		.owner	= THIS_MODULE,
192 		.pm	= &cyttsp4_pm_ops,
193 	},
194 	.probe  = cyttsp4_spi_probe,
195 	.remove = cyttsp4_spi_remove,
196 };
197 
198 module_spi_driver(cyttsp4_spi_driver);
199 
200 MODULE_LICENSE("GPL");
201 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
202 MODULE_AUTHOR("Cypress");
203 MODULE_ALIAS("spi:cyttsp4");
204