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_WR_OP 0x00 /* r/~w */ 24 #define CY_SPI_RD_OP 0x01 25 #define CY_SPI_CMD_BYTES 4 26 #define CY_SPI_SYNC_BYTE 2 27 #define CY_SPI_SYNC_ACK1 0x62 /* from protocol v.2 */ 28 #define CY_SPI_SYNC_ACK2 0x9D /* from protocol v.2 */ 29 #define CY_SPI_DATA_SIZE 128 30 #define CY_SPI_DATA_BUF_SIZE (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE) 31 #define CY_SPI_BITS_PER_WORD 8 32 33 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf, 34 u8 op, u16 reg, u8 *buf, int length) 35 { 36 struct spi_device *spi = to_spi_device(dev); 37 struct spi_message msg; 38 struct spi_transfer xfer[2]; 39 u8 *wr_buf = &xfer_buf[0]; 40 u8 *rd_buf = &xfer_buf[CY_SPI_DATA_BUF_SIZE]; 41 int retval; 42 int i; 43 44 if (length > CY_SPI_DATA_SIZE) { 45 dev_err(dev, "%s: length %d is too big.\n", 46 __func__, length); 47 return -EINVAL; 48 } 49 50 memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE); 51 memset(rd_buf, 0, CY_SPI_DATA_BUF_SIZE); 52 53 wr_buf[0] = 0x00; /* header byte 0 */ 54 wr_buf[1] = 0xFF; /* header byte 1 */ 55 wr_buf[2] = reg; /* reg index */ 56 wr_buf[3] = op; /* r/~w */ 57 if (op == CY_SPI_WR_OP) 58 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length); 59 60 memset(xfer, 0, sizeof(xfer)); 61 spi_message_init(&msg); 62 63 /* 64 We set both TX and RX buffers because Cypress TTSP 65 requires full duplex operation. 66 */ 67 xfer[0].tx_buf = wr_buf; 68 xfer[0].rx_buf = rd_buf; 69 switch (op) { 70 case CY_SPI_WR_OP: 71 xfer[0].len = length + CY_SPI_CMD_BYTES; 72 spi_message_add_tail(&xfer[0], &msg); 73 break; 74 75 case CY_SPI_RD_OP: 76 xfer[0].len = CY_SPI_CMD_BYTES; 77 spi_message_add_tail(&xfer[0], &msg); 78 79 xfer[1].rx_buf = buf; 80 xfer[1].len = length; 81 spi_message_add_tail(&xfer[1], &msg); 82 break; 83 84 default: 85 dev_err(dev, "%s: bad operation code=%d\n", __func__, op); 86 return -EINVAL; 87 } 88 89 retval = spi_sync(spi, &msg); 90 if (retval < 0) { 91 dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n", 92 __func__, retval, xfer[1].len, op); 93 94 /* 95 * do not return here since was a bad ACK sequence 96 * let the following ACK check handle any errors and 97 * allow silent retries 98 */ 99 } 100 101 if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK1 || 102 rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) { 103 dev_dbg(dev, "%s: operation %d failed\n", __func__, op); 104 105 for (i = 0; i < CY_SPI_CMD_BYTES; i++) 106 dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n", 107 __func__, i, rd_buf[i]); 108 for (i = 0; i < length; i++) 109 dev_dbg(dev, "%s: test buf[%d]:0x%02x\n", 110 __func__, i, buf[i]); 111 112 return -EIO; 113 } 114 115 return 0; 116 } 117 118 static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf, 119 u16 addr, u8 length, void *data) 120 { 121 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data, 122 length); 123 } 124 125 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf, 126 u16 addr, u8 length, const void *data) 127 { 128 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data, 129 length); 130 } 131 132 static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = { 133 .bustype = BUS_SPI, 134 .write = cyttsp_spi_write_block_data, 135 .read = cyttsp_spi_read_block_data, 136 }; 137 138 static int cyttsp_spi_probe(struct spi_device *spi) 139 { 140 struct cyttsp *ts; 141 int error; 142 143 /* Set up SPI*/ 144 spi->bits_per_word = CY_SPI_BITS_PER_WORD; 145 spi->mode = SPI_MODE_0; 146 error = spi_setup(spi); 147 if (error < 0) { 148 dev_err(&spi->dev, "%s: SPI setup error %d\n", 149 __func__, error); 150 return error; 151 } 152 153 ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq, 154 CY_SPI_DATA_BUF_SIZE * 2); 155 if (IS_ERR(ts)) 156 return PTR_ERR(ts); 157 158 spi_set_drvdata(spi, ts); 159 160 return 0; 161 } 162 163 static struct spi_driver cyttsp_spi_driver = { 164 .driver = { 165 .name = CY_SPI_NAME, 166 .pm = &cyttsp_pm_ops, 167 }, 168 .probe = cyttsp_spi_probe, 169 }; 170 171 module_spi_driver(cyttsp_spi_driver); 172 173 MODULE_LICENSE("GPL"); 174 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver"); 175 MODULE_AUTHOR("Cypress"); 176 MODULE_ALIAS("spi:cyttsp"); 177