drivers/input/touchscreen/cyttsp_spi.c

   1 /*
   2  * Source for:
   3  * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
   4  * For use with Cypress Txx3xx parts.
   5  * Supported parts include:
   6  * CY8CTST341
   7  * CY8CTMA340
   8  *
   9  * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
  10  * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * version 2, and only version 2, as published by the
  15  * Free Software Foundation.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License along
  23  * with this program; if not, write to the Free Software Foundation, Inc.,
  24  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  25  *
  26  * Contact Cypress Semiconductor at www.cypress.com <kev@cypress.com>
  27  *
  28  */
  29
  30 #include "cyttsp_core.h"
  31
  32 #include <linux/delay.h>
  33 #include <linux/input.h>
  34 #include <linux/spi/spi.h>
  35
  36 #define CY_SPI_WR_OP            0x00 /* r/~w */
  37 #define CY_SPI_RD_OP            0x01
  38 #define CY_SPI_CMD_BYTES        4
  39 #define CY_SPI_SYNC_BYTE        2
  40 #define CY_SPI_SYNC_ACK1        0x62 /* from protocol v.2 */
  41 #define CY_SPI_SYNC_ACK2        0x9D /* from protocol v.2 */
  42 #define CY_SPI_DATA_SIZE        128
  43 #define CY_SPI_DATA_BUF_SIZE    (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
  44 #define CY_SPI_BITS_PER_WORD    8
  45
  46 static int cyttsp_spi_xfer(struct cyttsp *ts,
  47                            u8 op, u8 reg, u8 *buf, int length)
  48 {
  49         struct spi_device *spi = to_spi_device(ts->dev);
  50         struct spi_message msg;
  51         struct spi_transfer xfer[2];
  52         u8 *wr_buf = &ts->xfer_buf[0];
  53         u8 *rd_buf = &ts->xfer_buf[CY_SPI_DATA_BUF_SIZE];
  54         int retval;
  55         int i;
  56
  57         if (length > CY_SPI_DATA_SIZE) {
  58                 dev_err(ts->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_DATA_BUF_SIZE);
  65
  66         wr_buf[0] = 0x00; /* header byte 0 */
  67         wr_buf[1] = 0xFF; /* header byte 1 */
  68         wr_buf[2] = reg;  /* reg index */
  69         wr_buf[3] = op;   /* r/~w */
  70         if (op == CY_SPI_WR_OP)
  71                 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
  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_CMD_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(ts->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(ts->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_ACK1 ||
 115             rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) {
 116
 117                 dev_dbg(ts->dev, "%s: operation %d failed\n", __func__, op);
 118
 119                 for (i = 0; i < CY_SPI_CMD_BYTES; i++)
 120                         dev_dbg(ts->dev, "%s: test rd_buf[%d]:0x%02x\n",
 121                                 __func__, i, rd_buf[i]);
 122                 for (i = 0; i < length; i++)
 123                         dev_dbg(ts->dev, "%s: test buf[%d]:0x%02x\n",
 124                                 __func__, i, buf[i]);
 125
 126                 return -EIO;
 127         }
 128
 129         return 0;
 130 }
 131
 132 static int cyttsp_spi_read_block_data(struct cyttsp *ts,
 133                                       u8 addr, u8 length, void *data)
 134 {
 135         return cyttsp_spi_xfer(ts, CY_SPI_RD_OP, addr, data, length);
 136 }
 137
 138 static int cyttsp_spi_write_block_data(struct cyttsp *ts,
 139                                        u8 addr, u8 length, const void *data)
 140 {
 141         return cyttsp_spi_xfer(ts, CY_SPI_WR_OP, addr, (void *)data, length);
 142 }
 143
 144 static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = {
 145         .bustype        = BUS_SPI,
 146         .write          = cyttsp_spi_write_block_data,
 147         .read           = cyttsp_spi_read_block_data,
 148 };
 149
 150 static int __devinit cyttsp_spi_probe(struct spi_device *spi)
 151 {
 152         struct cyttsp *ts;
 153         int error;
 154
 155         /* Set up SPI*/
 156         spi->bits_per_word = CY_SPI_BITS_PER_WORD;
 157         spi->mode = SPI_MODE_0;
 158         error = spi_setup(spi);
 159         if (error < 0) {
 160                 dev_err(&spi->dev, "%s: SPI setup error %d\n",
 161                         __func__, error);
 162                 return error;
 163         }
 164
 165         ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
 166                           CY_SPI_DATA_BUF_SIZE * 2);
 167         if (IS_ERR(ts))
 168                 return PTR_ERR(ts);
 169
 170         spi_set_drvdata(spi, ts);
 171
 172         return 0;
 173 }
 174
 175 static int __devexit cyttsp_spi_remove(struct spi_device *spi)
 176 {
 177         struct cyttsp *ts = spi_get_drvdata(spi);
 178
 179         cyttsp_remove(ts);
 180
 181         return 0;
 182 }
 183
 184 static struct spi_driver cyttsp_spi_driver = {
 185         .driver = {
 186                 .name   = CY_SPI_NAME,
 187                 .owner  = THIS_MODULE,
 188                 .pm     = &cyttsp_pm_ops,
 189         },
 190         .probe  = cyttsp_spi_probe,
 191         .remove = __devexit_p(cyttsp_spi_remove),
 192 };
 193
 194 module_spi_driver(cyttsp_spi_driver);
 195
 196 MODULE_ALIAS("spi:cyttsp");
 197 MODULE_LICENSE("GPL");
 198 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
 199 MODULE_AUTHOR("Cypress");
 200 MODULE_ALIAS("spi:cyttsp");