drivers/input/touchscreen/cyttsp_spi.c

   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");