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 
cyttsp_spi_xfer(struct device * dev,u8 * xfer_buf,u8 op,u16 reg,u8 * buf,int length)36 static 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 
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 	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 
cyttsp_spi_write_block_data(struct device * dev,u8 * xfer_buf,u16 addr,u8 length,const void * data)133 static 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 
140 static 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 
cyttsp4_spi_probe(struct spi_device * spi)146 static 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 
cyttsp4_spi_remove(struct spi_device * spi)167 static void cyttsp4_spi_remove(struct spi_device *spi)
168 {
169 	struct cyttsp4 *ts = spi_get_drvdata(spi);
170 	cyttsp4_remove(ts);
171 }
172 
173 static 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 
182 module_spi_driver(cyttsp4_spi_driver);
183 
184 MODULE_LICENSE("GPL");
185 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
186 MODULE_AUTHOR("Cypress");
187 MODULE_ALIAS("spi:cyttsp4");
188