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
46static 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
130static 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
143static 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
150static 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
156static 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	return PTR_ERR_OR_ZERO(ts);
175}
176
177static int cyttsp4_spi_remove(struct spi_device *spi)
178{
179	struct cyttsp4 *ts = spi_get_drvdata(spi);
180	cyttsp4_remove(ts);
181
182	return 0;
183}
184
185static struct spi_driver cyttsp4_spi_driver = {
186	.driver = {
187		.name	= CYTTSP4_SPI_NAME,
188		.pm	= &cyttsp4_pm_ops,
189	},
190	.probe  = cyttsp4_spi_probe,
191	.remove = cyttsp4_spi_remove,
192};
193
194module_spi_driver(cyttsp4_spi_driver);
195
196MODULE_LICENSE("GPL");
197MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
198MODULE_AUTHOR("Cypress");
199MODULE_ALIAS("spi:cyttsp4");
200