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 Txx3xx parts. 6 * Supported parts include: 7 * CY8CTST341 8 * CY8CTMA340 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 "cyttsp_core.h" 18 19 #include <linux/delay.h> 20 #include <linux/input.h> 21 #include <linux/spi/spi.h> 22 23 #define CY_SPI_NAME "cyttsp-spi" 24 25 #define CY_SPI_WR_OP 0x00 /* r/~w */ 26 #define CY_SPI_RD_OP 0x01 27 #define CY_SPI_CMD_BYTES 4 28 #define CY_SPI_SYNC_BYTE 2 29 #define CY_SPI_SYNC_ACK1 0x62 /* from protocol v.2 */ 30 #define CY_SPI_SYNC_ACK2 0x9D /* from protocol v.2 */ 31 #define CY_SPI_DATA_SIZE 128 32 #define CY_SPI_DATA_BUF_SIZE (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE) 33 #define CY_SPI_BITS_PER_WORD 8 34 35 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf, 36 u8 op, u16 reg, u8 *buf, int length) 37 { 38 struct spi_device *spi = to_spi_device(dev); 39 struct spi_message msg; 40 struct spi_transfer xfer[2]; 41 u8 *wr_buf = &xfer_buf[0]; 42 u8 *rd_buf = &xfer_buf[CY_SPI_DATA_BUF_SIZE]; 43 int retval; 44 int i; 45 46 if (length > CY_SPI_DATA_SIZE) { 47 dev_err(dev, "%s: length %d is too big.\n", 48 __func__, length); 49 return -EINVAL; 50 } 51 52 memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE); 53 memset(rd_buf, 0, CY_SPI_DATA_BUF_SIZE); 54 55 wr_buf[0] = 0x00; /* header byte 0 */ 56 wr_buf[1] = 0xFF; /* header byte 1 */ 57 wr_buf[2] = reg; /* reg index */ 58 wr_buf[3] = op; /* r/~w */ 59 if (op == CY_SPI_WR_OP) 60 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length); 61 62 memset(xfer, 0, sizeof(xfer)); 63 spi_message_init(&msg); 64 65 /* 66 We set both TX and RX buffers because Cypress TTSP 67 requires full duplex operation. 68 */ 69 xfer[0].tx_buf = wr_buf; 70 xfer[0].rx_buf = rd_buf; 71 switch (op) { 72 case CY_SPI_WR_OP: 73 xfer[0].len = length + CY_SPI_CMD_BYTES; 74 spi_message_add_tail(&xfer[0], &msg); 75 break; 76 77 case CY_SPI_RD_OP: 78 xfer[0].len = CY_SPI_CMD_BYTES; 79 spi_message_add_tail(&xfer[0], &msg); 80 81 xfer[1].rx_buf = buf; 82 xfer[1].len = length; 83 spi_message_add_tail(&xfer[1], &msg); 84 break; 85 86 default: 87 dev_err(dev, "%s: bad operation code=%d\n", __func__, op); 88 return -EINVAL; 89 } 90 91 retval = spi_sync(spi, &msg); 92 if (retval < 0) { 93 dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n", 94 __func__, retval, xfer[1].len, op); 95 96 /* 97 * do not return here since was a bad ACK sequence 98 * let the following ACK check handle any errors and 99 * allow silent retries 100 */ 101 } 102 103 if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK1 || 104 rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) { 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 } 119 120 static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf, 121 u16 addr, u8 length, void *data) 122 { 123 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data, 124 length); 125 } 126 127 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf, 128 u16 addr, u8 length, const void *data) 129 { 130 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data, 131 length); 132 } 133 134 static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = { 135 .bustype = BUS_SPI, 136 .write = cyttsp_spi_write_block_data, 137 .read = cyttsp_spi_read_block_data, 138 }; 139 140 static int cyttsp_spi_probe(struct spi_device *spi) 141 { 142 struct cyttsp *ts; 143 int error; 144 145 /* Set up SPI*/ 146 spi->bits_per_word = CY_SPI_BITS_PER_WORD; 147 spi->mode = SPI_MODE_0; 148 error = spi_setup(spi); 149 if (error < 0) { 150 dev_err(&spi->dev, "%s: SPI setup error %d\n", 151 __func__, error); 152 return error; 153 } 154 155 ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq, 156 CY_SPI_DATA_BUF_SIZE * 2); 157 if (IS_ERR(ts)) 158 return PTR_ERR(ts); 159 160 spi_set_drvdata(spi, ts); 161 162 return 0; 163 } 164 165 static const struct of_device_id cyttsp_of_spi_match[] = { 166 { .compatible = "cypress,cy8ctma340", }, 167 { .compatible = "cypress,cy8ctst341", }, 168 { /* sentinel */ } 169 }; 170 MODULE_DEVICE_TABLE(of, cyttsp_of_spi_match); 171 172 static struct spi_driver cyttsp_spi_driver = { 173 .driver = { 174 .name = CY_SPI_NAME, 175 .pm = &cyttsp_pm_ops, 176 .of_match_table = cyttsp_of_spi_match, 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