1 /* 2 * Source for: 3 * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver. 4 * For use with Cypress Txx4xx parts. 5 * Supported parts include: 6 * TMA4XX 7 * TMA1036 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 "cyttsp4_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_BITS_PER_WORD 8 36 #define CY_SPI_A8_BIT 0x02 37 #define CY_SPI_WR_HEADER_BYTES 2 38 #define CY_SPI_RD_HEADER_BYTES 1 39 #define CY_SPI_CMD_BYTES 2 40 #define CY_SPI_SYNC_BYTE 0 41 #define CY_SPI_SYNC_ACK 0x62 /* from TRM *A protocol */ 42 #define CY_SPI_DATA_SIZE (2 * 256) 43 44 #define CY_SPI_DATA_BUF_SIZE (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE) 45 46 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf, 47 u8 op, u16 reg, u8 *buf, int length) 48 { 49 struct spi_device *spi = to_spi_device(dev); 50 struct spi_message msg; 51 struct spi_transfer xfer[2]; 52 u8 *wr_buf = &xfer_buf[0]; 53 u8 rd_buf[CY_SPI_CMD_BYTES]; 54 int retval; 55 int i; 56 57 if (length > CY_SPI_DATA_SIZE) { 58 dev_err(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_CMD_BYTES); 65 66 wr_buf[0] = op + (((reg >> 8) & 0x1) ? CY_SPI_A8_BIT : 0); 67 if (op == CY_SPI_WR_OP) { 68 wr_buf[1] = reg & 0xFF; 69 if (length > 0) 70 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length); 71 } 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_RD_HEADER_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(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(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_ACK) { 115 dev_dbg(dev, "%s: operation %d failed\n", __func__, op); 116 117 for (i = 0; i < CY_SPI_CMD_BYTES; i++) 118 dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n", 119 __func__, i, rd_buf[i]); 120 for (i = 0; i < length; i++) 121 dev_dbg(dev, "%s: test buf[%d]:0x%02x\n", 122 __func__, i, buf[i]); 123 124 return -EIO; 125 } 126 127 return 0; 128 } 129 130 static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf, 131 u16 addr, u8 length, void *data) 132 { 133 int rc; 134 135 rc = cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, NULL, 0); 136 if (rc) 137 return rc; 138 else 139 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data, 140 length); 141 } 142 143 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf, 144 u16 addr, u8 length, const void *data) 145 { 146 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data, 147 length); 148 } 149 150 static const struct cyttsp4_bus_ops cyttsp_spi_bus_ops = { 151 .bustype = BUS_SPI, 152 .write = cyttsp_spi_write_block_data, 153 .read = cyttsp_spi_read_block_data, 154 }; 155 156 static int cyttsp4_spi_probe(struct spi_device *spi) 157 { 158 struct cyttsp4 *ts; 159 int error; 160 161 /* Set up SPI*/ 162 spi->bits_per_word = CY_SPI_BITS_PER_WORD; 163 spi->mode = SPI_MODE_0; 164 error = spi_setup(spi); 165 if (error < 0) { 166 dev_err(&spi->dev, "%s: SPI setup error %d\n", 167 __func__, error); 168 return error; 169 } 170 171 ts = cyttsp4_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq, 172 CY_SPI_DATA_BUF_SIZE); 173 174 return PTR_ERR_OR_ZERO(ts); 175 } 176 177 static int cyttsp4_spi_remove(struct spi_device *spi) 178 { 179 struct cyttsp4 *ts = spi_get_drvdata(spi); 180 cyttsp4_remove(ts); 181 182 return 0; 183 } 184 185 static struct spi_driver cyttsp4_spi_driver = { 186 .driver = { 187 .name = CYTTSP4_SPI_NAME, 188 .owner = THIS_MODULE, 189 .pm = &cyttsp4_pm_ops, 190 }, 191 .probe = cyttsp4_spi_probe, 192 .remove = cyttsp4_spi_remove, 193 }; 194 195 module_spi_driver(cyttsp4_spi_driver); 196 197 MODULE_LICENSE("GPL"); 198 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver"); 199 MODULE_AUTHOR("Cypress"); 200 MODULE_ALIAS("spi:cyttsp4"); 201