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 * Copyright (C) 2013 Cypress Semiconductor 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License 15 * version 2, and only version 2, as published by the 16 * Free Software Foundation. 17 * 18 * This program is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 * GNU General Public License for more details. 22 * 23 * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com> 24 * 25 */ 26 27 #include "cyttsp_core.h" 28 29 #include <linux/delay.h> 30 #include <linux/input.h> 31 #include <linux/spi/spi.h> 32 33 #define CY_SPI_WR_OP 0x00 /* r/~w */ 34 #define CY_SPI_RD_OP 0x01 35 #define CY_SPI_CMD_BYTES 4 36 #define CY_SPI_SYNC_BYTE 2 37 #define CY_SPI_SYNC_ACK1 0x62 /* from protocol v.2 */ 38 #define CY_SPI_SYNC_ACK2 0x9D /* from protocol v.2 */ 39 #define CY_SPI_DATA_SIZE 128 40 #define CY_SPI_DATA_BUF_SIZE (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE) 41 #define CY_SPI_BITS_PER_WORD 8 42 43 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf, 44 u8 op, u16 reg, u8 *buf, int length) 45 { 46 struct spi_device *spi = to_spi_device(dev); 47 struct spi_message msg; 48 struct spi_transfer xfer[2]; 49 u8 *wr_buf = &xfer_buf[0]; 50 u8 *rd_buf = &xfer_buf[CY_SPI_DATA_BUF_SIZE]; 51 int retval; 52 int i; 53 54 if (length > CY_SPI_DATA_SIZE) { 55 dev_err(dev, "%s: length %d is too big.\n", 56 __func__, length); 57 return -EINVAL; 58 } 59 60 memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE); 61 memset(rd_buf, 0, CY_SPI_DATA_BUF_SIZE); 62 63 wr_buf[0] = 0x00; /* header byte 0 */ 64 wr_buf[1] = 0xFF; /* header byte 1 */ 65 wr_buf[2] = reg; /* reg index */ 66 wr_buf[3] = op; /* r/~w */ 67 if (op == CY_SPI_WR_OP) 68 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length); 69 70 memset(xfer, 0, sizeof(xfer)); 71 spi_message_init(&msg); 72 73 /* 74 We set both TX and RX buffers because Cypress TTSP 75 requires full duplex operation. 76 */ 77 xfer[0].tx_buf = wr_buf; 78 xfer[0].rx_buf = rd_buf; 79 switch (op) { 80 case CY_SPI_WR_OP: 81 xfer[0].len = length + CY_SPI_CMD_BYTES; 82 spi_message_add_tail(&xfer[0], &msg); 83 break; 84 85 case CY_SPI_RD_OP: 86 xfer[0].len = CY_SPI_CMD_BYTES; 87 spi_message_add_tail(&xfer[0], &msg); 88 89 xfer[1].rx_buf = buf; 90 xfer[1].len = length; 91 spi_message_add_tail(&xfer[1], &msg); 92 break; 93 94 default: 95 dev_err(dev, "%s: bad operation code=%d\n", __func__, op); 96 return -EINVAL; 97 } 98 99 retval = spi_sync(spi, &msg); 100 if (retval < 0) { 101 dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n", 102 __func__, retval, xfer[1].len, op); 103 104 /* 105 * do not return here since was a bad ACK sequence 106 * let the following ACK check handle any errors and 107 * allow silent retries 108 */ 109 } 110 111 if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK1 || 112 rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) { 113 dev_dbg(dev, "%s: operation %d failed\n", __func__, op); 114 115 for (i = 0; i < CY_SPI_CMD_BYTES; i++) 116 dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n", 117 __func__, i, rd_buf[i]); 118 for (i = 0; i < length; i++) 119 dev_dbg(dev, "%s: test buf[%d]:0x%02x\n", 120 __func__, i, buf[i]); 121 122 return -EIO; 123 } 124 125 return 0; 126 } 127 128 static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf, 129 u16 addr, u8 length, void *data) 130 { 131 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data, 132 length); 133 } 134 135 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf, 136 u16 addr, u8 length, const void *data) 137 { 138 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data, 139 length); 140 } 141 142 static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = { 143 .bustype = BUS_SPI, 144 .write = cyttsp_spi_write_block_data, 145 .read = cyttsp_spi_read_block_data, 146 }; 147 148 static int cyttsp_spi_probe(struct spi_device *spi) 149 { 150 struct cyttsp *ts; 151 int error; 152 153 /* Set up SPI*/ 154 spi->bits_per_word = CY_SPI_BITS_PER_WORD; 155 spi->mode = SPI_MODE_0; 156 error = spi_setup(spi); 157 if (error < 0) { 158 dev_err(&spi->dev, "%s: SPI setup error %d\n", 159 __func__, error); 160 return error; 161 } 162 163 ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq, 164 CY_SPI_DATA_BUF_SIZE * 2); 165 if (IS_ERR(ts)) 166 return PTR_ERR(ts); 167 168 spi_set_drvdata(spi, ts); 169 170 return 0; 171 } 172 173 static struct spi_driver cyttsp_spi_driver = { 174 .driver = { 175 .name = CY_SPI_NAME, 176 .pm = &cyttsp_pm_ops, 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