1 /* 2 * Source for: 3 * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver. 4 * For use with Cypress Txx3xx parts. 5 * Supported parts include: 6 * CY8CTST341 7 * CY8CTMA340 8 * 9 * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc. 10 * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org> 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * version 2, and only version 2, as published by the 15 * Free Software Foundation. 16 * 17 * This program is distributed in the hope that it will be useful, 18 * but WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20 * GNU General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License along 23 * with this program; if not, write to the Free Software Foundation, Inc., 24 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 25 * 26 * Contact Cypress Semiconductor at www.cypress.com <kev@cypress.com> 27 * 28 */ 29 30 #include "cyttsp_core.h" 31 32 #include <linux/delay.h> 33 #include <linux/input.h> 34 #include <linux/spi/spi.h> 35 36 #define CY_SPI_WR_OP 0x00 /* r/~w */ 37 #define CY_SPI_RD_OP 0x01 38 #define CY_SPI_CMD_BYTES 4 39 #define CY_SPI_SYNC_BYTE 2 40 #define CY_SPI_SYNC_ACK1 0x62 /* from protocol v.2 */ 41 #define CY_SPI_SYNC_ACK2 0x9D /* from protocol v.2 */ 42 #define CY_SPI_DATA_SIZE 128 43 #define CY_SPI_DATA_BUF_SIZE (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE) 44 #define CY_SPI_BITS_PER_WORD 8 45 46 static int cyttsp_spi_xfer(struct cyttsp *ts, 47 u8 op, u8 reg, u8 *buf, int length) 48 { 49 struct spi_device *spi = to_spi_device(ts->dev); 50 struct spi_message msg; 51 struct spi_transfer xfer[2]; 52 u8 *wr_buf = &ts->xfer_buf[0]; 53 u8 *rd_buf = &ts->xfer_buf[CY_SPI_DATA_BUF_SIZE]; 54 int retval; 55 int i; 56 57 if (length > CY_SPI_DATA_SIZE) { 58 dev_err(ts->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_DATA_BUF_SIZE); 65 66 wr_buf[0] = 0x00; /* header byte 0 */ 67 wr_buf[1] = 0xFF; /* header byte 1 */ 68 wr_buf[2] = reg; /* reg index */ 69 wr_buf[3] = op; /* r/~w */ 70 if (op == CY_SPI_WR_OP) 71 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length); 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_CMD_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(ts->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(ts->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_ACK1 || 115 rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) { 116 117 dev_dbg(ts->dev, "%s: operation %d failed\n", __func__, op); 118 119 for (i = 0; i < CY_SPI_CMD_BYTES; i++) 120 dev_dbg(ts->dev, "%s: test rd_buf[%d]:0x%02x\n", 121 __func__, i, rd_buf[i]); 122 for (i = 0; i < length; i++) 123 dev_dbg(ts->dev, "%s: test buf[%d]:0x%02x\n", 124 __func__, i, buf[i]); 125 126 return -EIO; 127 } 128 129 return 0; 130 } 131 132 static int cyttsp_spi_read_block_data(struct cyttsp *ts, 133 u8 addr, u8 length, void *data) 134 { 135 return cyttsp_spi_xfer(ts, CY_SPI_RD_OP, addr, data, length); 136 } 137 138 static int cyttsp_spi_write_block_data(struct cyttsp *ts, 139 u8 addr, u8 length, const void *data) 140 { 141 return cyttsp_spi_xfer(ts, CY_SPI_WR_OP, addr, (void *)data, length); 142 } 143 144 static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = { 145 .bustype = BUS_SPI, 146 .write = cyttsp_spi_write_block_data, 147 .read = cyttsp_spi_read_block_data, 148 }; 149 150 static int cyttsp_spi_probe(struct spi_device *spi) 151 { 152 struct cyttsp *ts; 153 int error; 154 155 /* Set up SPI*/ 156 spi->bits_per_word = CY_SPI_BITS_PER_WORD; 157 spi->mode = SPI_MODE_0; 158 error = spi_setup(spi); 159 if (error < 0) { 160 dev_err(&spi->dev, "%s: SPI setup error %d\n", 161 __func__, error); 162 return error; 163 } 164 165 ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq, 166 CY_SPI_DATA_BUF_SIZE * 2); 167 if (IS_ERR(ts)) 168 return PTR_ERR(ts); 169 170 spi_set_drvdata(spi, ts); 171 172 return 0; 173 } 174 175 static int cyttsp_spi_remove(struct spi_device *spi) 176 { 177 struct cyttsp *ts = spi_get_drvdata(spi); 178 179 cyttsp_remove(ts); 180 181 return 0; 182 } 183 184 static struct spi_driver cyttsp_spi_driver = { 185 .driver = { 186 .name = CY_SPI_NAME, 187 .owner = THIS_MODULE, 188 .pm = &cyttsp_pm_ops, 189 }, 190 .probe = cyttsp_spi_probe, 191 .remove = cyttsp_spi_remove, 192 }; 193 194 module_spi_driver(cyttsp_spi_driver); 195 196 MODULE_ALIAS("spi:cyttsp"); 197 MODULE_LICENSE("GPL"); 198 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver"); 199 MODULE_AUTHOR("Cypress"); 200 MODULE_ALIAS("spi:cyttsp"); 201