xref: /linux/drivers/input/touchscreen/cyttsp_spi.c (revision cdc780f044a803aff8845b949f800f0f3d095d5f)
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 Txx3xx parts.
6  * Supported parts include:
7  * CY8CTST341
8  * CY8CTMA340
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 "cyttsp_core.h"
18 
19 #include <linux/delay.h>
20 #include <linux/input.h>
21 #include <linux/spi/spi.h>
22 
23 #define CY_SPI_NAME		"cyttsp-spi"
24 
25 #define CY_SPI_WR_OP		0x00 /* r/~w */
26 #define CY_SPI_RD_OP		0x01
27 #define CY_SPI_CMD_BYTES	4
28 #define CY_SPI_SYNC_BYTE	2
29 #define CY_SPI_SYNC_ACK1	0x62 /* from protocol v.2 */
30 #define CY_SPI_SYNC_ACK2	0x9D /* from protocol v.2 */
31 #define CY_SPI_DATA_SIZE	128
32 #define CY_SPI_DATA_BUF_SIZE	(CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
33 #define CY_SPI_BITS_PER_WORD	8
34 
cyttsp_spi_xfer(struct device * dev,u8 * xfer_buf,u8 op,u16 reg,u8 * buf,int length)35 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
36 			   u8 op, u16 reg, u8 *buf, int length)
37 {
38 	struct spi_device *spi = to_spi_device(dev);
39 	struct spi_message msg;
40 	struct spi_transfer xfer[2];
41 	u8 *wr_buf = &xfer_buf[0];
42 	u8 *rd_buf = &xfer_buf[CY_SPI_DATA_BUF_SIZE];
43 	int retval;
44 	int i;
45 
46 	if (length > CY_SPI_DATA_SIZE) {
47 		dev_err(dev, "%s: length %d is too big.\n",
48 			__func__, length);
49 		return -EINVAL;
50 	}
51 
52 	memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE);
53 	memset(rd_buf, 0, CY_SPI_DATA_BUF_SIZE);
54 
55 	wr_buf[0] = 0x00; /* header byte 0 */
56 	wr_buf[1] = 0xFF; /* header byte 1 */
57 	wr_buf[2] = reg;  /* reg index */
58 	wr_buf[3] = op;   /* r/~w */
59 	if (op == CY_SPI_WR_OP)
60 		memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
61 
62 	memset(xfer, 0, sizeof(xfer));
63 	spi_message_init(&msg);
64 
65 	/*
66 	  We set both TX and RX buffers because Cypress TTSP
67 	  requires full duplex operation.
68 	*/
69 	xfer[0].tx_buf = wr_buf;
70 	xfer[0].rx_buf = rd_buf;
71 	switch (op) {
72 	case CY_SPI_WR_OP:
73 		xfer[0].len = length + CY_SPI_CMD_BYTES;
74 		spi_message_add_tail(&xfer[0], &msg);
75 		break;
76 
77 	case CY_SPI_RD_OP:
78 		xfer[0].len = CY_SPI_CMD_BYTES;
79 		spi_message_add_tail(&xfer[0], &msg);
80 
81 		xfer[1].rx_buf = buf;
82 		xfer[1].len = length;
83 		spi_message_add_tail(&xfer[1], &msg);
84 		break;
85 
86 	default:
87 		dev_err(dev, "%s: bad operation code=%d\n", __func__, op);
88 		return -EINVAL;
89 	}
90 
91 	retval = spi_sync(spi, &msg);
92 	if (retval < 0) {
93 		dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n",
94 			__func__, retval, xfer[1].len, op);
95 
96 		/*
97 		 * do not return here since was a bad ACK sequence
98 		 * let the following ACK check handle any errors and
99 		 * allow silent retries
100 		 */
101 	}
102 
103 	if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK1 ||
104 	    rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) {
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 
cyttsp_spi_read_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,void * data)120 static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
121 				      u16 addr, u8 length, void *data)
122 {
123 	return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
124 			length);
125 }
126 
cyttsp_spi_write_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,const void * data)127 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
128 				       u16 addr, u8 length, const void *data)
129 {
130 	return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
131 			length);
132 }
133 
134 static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = {
135 	.bustype	= BUS_SPI,
136 	.write		= cyttsp_spi_write_block_data,
137 	.read		= cyttsp_spi_read_block_data,
138 };
139 
cyttsp_spi_probe(struct spi_device * spi)140 static int cyttsp_spi_probe(struct spi_device *spi)
141 {
142 	struct cyttsp *ts;
143 	int error;
144 
145 	/* Set up SPI*/
146 	spi->bits_per_word = CY_SPI_BITS_PER_WORD;
147 	spi->mode = SPI_MODE_0;
148 	error = spi_setup(spi);
149 	if (error < 0) {
150 		dev_err(&spi->dev, "%s: SPI setup error %d\n",
151 			__func__, error);
152 		return error;
153 	}
154 
155 	ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
156 			  CY_SPI_DATA_BUF_SIZE * 2);
157 	if (IS_ERR(ts))
158 		return PTR_ERR(ts);
159 
160 	spi_set_drvdata(spi, ts);
161 
162 	return 0;
163 }
164 
165 static const struct of_device_id cyttsp_of_spi_match[] = {
166 	{ .compatible = "cypress,cy8ctma340", },
167 	{ .compatible = "cypress,cy8ctst341", },
168 	{ /* sentinel */ }
169 };
170 MODULE_DEVICE_TABLE(of, cyttsp_of_spi_match);
171 
172 static struct spi_driver cyttsp_spi_driver = {
173 	.driver = {
174 		.name	= CY_SPI_NAME,
175 		.pm	= pm_sleep_ptr(&cyttsp_pm_ops),
176 		.of_match_table = cyttsp_of_spi_match,
177 	},
178 	.probe  = cyttsp_spi_probe,
179 };
180 
181 module_spi_driver(cyttsp_spi_driver);
182 
183 MODULE_LICENSE("GPL");
184 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
185 MODULE_AUTHOR("Cypress");
186 MODULE_ALIAS("spi:cyttsp");
187