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 Txx4xx parts. 6 * Supported parts include: 7 * TMA4XX 8 * TMA1036 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 "cyttsp4_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_BITS_PER_WORD 8 26 #define CY_SPI_A8_BIT 0x02 27 #define CY_SPI_WR_HEADER_BYTES 2 28 #define CY_SPI_RD_HEADER_BYTES 1 29 #define CY_SPI_CMD_BYTES 2 30 #define CY_SPI_SYNC_BYTE 0 31 #define CY_SPI_SYNC_ACK 0x62 /* from TRM *A protocol */ 32 #define CY_SPI_DATA_SIZE (2 * 256) 33 34 #define CY_SPI_DATA_BUF_SIZE (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE) 35 36 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf, 37 u8 op, u16 reg, u8 *buf, int length) 38 { 39 struct spi_device *spi = to_spi_device(dev); 40 struct spi_message msg; 41 struct spi_transfer xfer[2]; 42 u8 *wr_buf = &xfer_buf[0]; 43 u8 rd_buf[CY_SPI_CMD_BYTES]; 44 int retval; 45 int i; 46 47 if (length > CY_SPI_DATA_SIZE) { 48 dev_err(dev, "%s: length %d is too big.\n", 49 __func__, length); 50 return -EINVAL; 51 } 52 53 memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE); 54 memset(rd_buf, 0, CY_SPI_CMD_BYTES); 55 56 wr_buf[0] = op + (((reg >> 8) & 0x1) ? CY_SPI_A8_BIT : 0); 57 if (op == CY_SPI_WR_OP) { 58 wr_buf[1] = reg & 0xFF; 59 if (length > 0) 60 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length); 61 } 62 63 memset(xfer, 0, sizeof(xfer)); 64 spi_message_init(&msg); 65 66 /* 67 We set both TX and RX buffers because Cypress TTSP 68 requires full duplex operation. 69 */ 70 xfer[0].tx_buf = wr_buf; 71 xfer[0].rx_buf = rd_buf; 72 switch (op) { 73 case CY_SPI_WR_OP: 74 xfer[0].len = length + CY_SPI_CMD_BYTES; 75 spi_message_add_tail(&xfer[0], &msg); 76 break; 77 78 case CY_SPI_RD_OP: 79 xfer[0].len = CY_SPI_RD_HEADER_BYTES; 80 spi_message_add_tail(&xfer[0], &msg); 81 82 xfer[1].rx_buf = buf; 83 xfer[1].len = length; 84 spi_message_add_tail(&xfer[1], &msg); 85 break; 86 87 default: 88 dev_err(dev, "%s: bad operation code=%d\n", __func__, op); 89 return -EINVAL; 90 } 91 92 retval = spi_sync(spi, &msg); 93 if (retval < 0) { 94 dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n", 95 __func__, retval, xfer[1].len, op); 96 97 /* 98 * do not return here since was a bad ACK sequence 99 * let the following ACK check handle any errors and 100 * allow silent retries 101 */ 102 } 103 104 if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK) { 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 int rc; 124 125 rc = cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, NULL, 0); 126 if (rc) 127 return rc; 128 else 129 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data, 130 length); 131 } 132 133 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf, 134 u16 addr, u8 length, const void *data) 135 { 136 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data, 137 length); 138 } 139 140 static const struct cyttsp4_bus_ops cyttsp_spi_bus_ops = { 141 .bustype = BUS_SPI, 142 .write = cyttsp_spi_write_block_data, 143 .read = cyttsp_spi_read_block_data, 144 }; 145 146 static int cyttsp4_spi_probe(struct spi_device *spi) 147 { 148 struct cyttsp4 *ts; 149 int error; 150 151 /* Set up SPI*/ 152 spi->bits_per_word = CY_SPI_BITS_PER_WORD; 153 spi->mode = SPI_MODE_0; 154 error = spi_setup(spi); 155 if (error < 0) { 156 dev_err(&spi->dev, "%s: SPI setup error %d\n", 157 __func__, error); 158 return error; 159 } 160 161 ts = cyttsp4_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq, 162 CY_SPI_DATA_BUF_SIZE); 163 164 return PTR_ERR_OR_ZERO(ts); 165 } 166 167 static int cyttsp4_spi_remove(struct spi_device *spi) 168 { 169 struct cyttsp4 *ts = spi_get_drvdata(spi); 170 cyttsp4_remove(ts); 171 172 return 0; 173 } 174 175 static struct spi_driver cyttsp4_spi_driver = { 176 .driver = { 177 .name = CYTTSP4_SPI_NAME, 178 .pm = &cyttsp4_pm_ops, 179 }, 180 .probe = cyttsp4_spi_probe, 181 .remove = cyttsp4_spi_remove, 182 }; 183 184 module_spi_driver(cyttsp4_spi_driver); 185 186 MODULE_LICENSE("GPL"); 187 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver"); 188 MODULE_AUTHOR("Cypress"); 189 MODULE_ALIAS("spi:cyttsp4"); 190