1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Source for:
4 * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
5 * For use with Cypress Txx4xx parts.
6 * Supported parts include:
7 * TMA4XX
8 * TMA1036
9 *
10 * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
11 * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
12 * Copyright (C) 2013 Cypress Semiconductor
13 *
14 * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com>
15 */
16
17#include "cyttsp4_core.h"
18
19#include <linux/delay.h>
20#include <linux/input.h>
21#include <linux/spi/spi.h>
22
23#define CY_SPI_WR_OP		0x00 /* r/~w */
24#define CY_SPI_RD_OP		0x01
25#define CY_SPI_BITS_PER_WORD	8
26#define CY_SPI_A8_BIT		0x02
27#define CY_SPI_WR_HEADER_BYTES	2
28#define CY_SPI_RD_HEADER_BYTES	1
29#define CY_SPI_CMD_BYTES	2
30#define CY_SPI_SYNC_BYTE	0
31#define CY_SPI_SYNC_ACK		0x62 /* from TRM *A protocol */
32#define CY_SPI_DATA_SIZE	(2 * 256)
33
34#define CY_SPI_DATA_BUF_SIZE	(CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
35
36static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
37			   u8 op, u16 reg, u8 *buf, int length)
38{
39	struct spi_device *spi = to_spi_device(dev);
40	struct spi_message msg;
41	struct spi_transfer xfer[2];
42	u8 *wr_buf = &xfer_buf[0];
43	u8 rd_buf[CY_SPI_CMD_BYTES];
44	int retval;
45	int i;
46
47	if (length > CY_SPI_DATA_SIZE) {
48		dev_err(dev, "%s: length %d is too big.\n",
49			__func__, length);
50		return -EINVAL;
51	}
52
53	memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE);
54	memset(rd_buf, 0, CY_SPI_CMD_BYTES);
55
56	wr_buf[0] = op + (((reg >> 8) & 0x1) ? CY_SPI_A8_BIT : 0);
57	if (op == CY_SPI_WR_OP) {
58		wr_buf[1] = reg & 0xFF;
59		if (length > 0)
60			memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
61	}
62
63	memset(xfer, 0, sizeof(xfer));
64	spi_message_init(&msg);
65
66	/*
67	  We set both TX and RX buffers because Cypress TTSP
68	  requires full duplex operation.
69	*/
70	xfer[0].tx_buf = wr_buf;
71	xfer[0].rx_buf = rd_buf;
72	switch (op) {
73	case CY_SPI_WR_OP:
74		xfer[0].len = length + CY_SPI_CMD_BYTES;
75		spi_message_add_tail(&xfer[0], &msg);
76		break;
77
78	case CY_SPI_RD_OP:
79		xfer[0].len = CY_SPI_RD_HEADER_BYTES;
80		spi_message_add_tail(&xfer[0], &msg);
81
82		xfer[1].rx_buf = buf;
83		xfer[1].len = length;
84		spi_message_add_tail(&xfer[1], &msg);
85		break;
86
87	default:
88		dev_err(dev, "%s: bad operation code=%d\n", __func__, op);
89		return -EINVAL;
90	}
91
92	retval = spi_sync(spi, &msg);
93	if (retval < 0) {
94		dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n",
95			__func__, retval, xfer[1].len, op);
96
97		/*
98		 * do not return here since was a bad ACK sequence
99		 * let the following ACK check handle any errors and
100		 * allow silent retries
101		 */
102	}
103
104	if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK) {
105		dev_dbg(dev, "%s: operation %d failed\n", __func__, op);
106
107		for (i = 0; i < CY_SPI_CMD_BYTES; i++)
108			dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n",
109				__func__, i, rd_buf[i]);
110		for (i = 0; i < length; i++)
111			dev_dbg(dev, "%s: test buf[%d]:0x%02x\n",
112				__func__, i, buf[i]);
113
114		return -EIO;
115	}
116
117	return 0;
118}
119
120static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
121				      u16 addr, u8 length, void *data)
122{
123	int rc;
124
125	rc = cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, NULL, 0);
126	if (rc)
127		return rc;
128	else
129		return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
130				length);
131}
132
133static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
134				       u16 addr, u8 length, const void *data)
135{
136	return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
137			length);
138}
139
140static const struct cyttsp4_bus_ops cyttsp_spi_bus_ops = {
141	.bustype	= BUS_SPI,
142	.write		= cyttsp_spi_write_block_data,
143	.read		= cyttsp_spi_read_block_data,
144};
145
146static int cyttsp4_spi_probe(struct spi_device *spi)
147{
148	struct cyttsp4 *ts;
149	int error;
150
151	/* Set up SPI*/
152	spi->bits_per_word = CY_SPI_BITS_PER_WORD;
153	spi->mode = SPI_MODE_0;
154	error = spi_setup(spi);
155	if (error < 0) {
156		dev_err(&spi->dev, "%s: SPI setup error %d\n",
157			__func__, error);
158		return error;
159	}
160
161	ts = cyttsp4_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
162			  CY_SPI_DATA_BUF_SIZE);
163
164	return PTR_ERR_OR_ZERO(ts);
165}
166
167static void cyttsp4_spi_remove(struct spi_device *spi)
168{
169	struct cyttsp4 *ts = spi_get_drvdata(spi);
170	cyttsp4_remove(ts);
171}
172
173static struct spi_driver cyttsp4_spi_driver = {
174	.driver = {
175		.name	= CYTTSP4_SPI_NAME,
176		.pm	= pm_ptr(&cyttsp4_pm_ops),
177	},
178	.probe  = cyttsp4_spi_probe,
179	.remove = cyttsp4_spi_remove,
180};
181
182module_spi_driver(cyttsp4_spi_driver);
183
184MODULE_LICENSE("GPL");
185MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
186MODULE_AUTHOR("Cypress");
187MODULE_ALIAS("spi:cyttsp4");
188