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