LXR linux/drivers/input/touchscreen/cyttsp4

   1/*
   2 * Source for:
   3 * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
   4 * For use with Cypress Txx4xx parts.
   5 * Supported parts include:
   6 * TMA4XX
   7 * TMA1036
   8 *
   9 * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
  10 * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
  11 * Copyright (C) 2013 Cypress Semiconductor
  12 *
  13 * This program is free software; you can redistribute it and/or
  14 * modify it under the terms of the GNU General Public License
  15 * version 2, and only version 2, as published by the
  16 * Free Software Foundation.
  17 *
  18 * This program is distributed in the hope that it will be useful,
  19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 * GNU General Public License for more details.
  22 *
  23 * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com>
  24 *
  25 */
  26
  27#include "cyttsp4_core.h"
  28
  29#include <linux/delay.h>
  30#include <linux/input.h>
  31#include <linux/spi/spi.h>
  32
  33#define CY_SPI_WR_OP            0x00 /* r/~w */
  34#define CY_SPI_RD_OP            0x01
  35#define CY_SPI_BITS_PER_WORD    8
  36#define CY_SPI_A8_BIT           0x02
  37#define CY_SPI_WR_HEADER_BYTES  2
  38#define CY_SPI_RD_HEADER_BYTES  1
  39#define CY_SPI_CMD_BYTES        2
  40#define CY_SPI_SYNC_BYTE        0
  41#define CY_SPI_SYNC_ACK         0x62 /* from TRM *A protocol */
  42#define CY_SPI_DATA_SIZE        (2 * 256)
  43
  44#define CY_SPI_DATA_BUF_SIZE    (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
  45
  46static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
  47                           u8 op, u16 reg, u8 *buf, int length)
  48{
  49        struct spi_device *spi = to_spi_device(dev);
  50        struct spi_message msg;
  51        struct spi_transfer xfer[2];
  52        u8 *wr_buf = &xfer_buf[0];
  53        u8 rd_buf[CY_SPI_CMD_BYTES];
  54        int retval;
  55        int i;
  56
  57        if (length > CY_SPI_DATA_SIZE) {
  58                dev_err(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_CMD_BYTES);
  65
  66        wr_buf[0] = op + (((reg >> 8) & 0x1) ? CY_SPI_A8_BIT : 0);
  67        if (op == CY_SPI_WR_OP) {
  68                wr_buf[1] = reg & 0xFF;
  69                if (length > 0)
  70                        memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
  71        }
  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_RD_HEADER_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(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(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_ACK) {
 115                dev_dbg(dev, "%s: operation %d failed\n", __func__, op);
 116
 117                for (i = 0; i < CY_SPI_CMD_BYTES; i++)
 118                        dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n",
 119                                __func__, i, rd_buf[i]);
 120                for (i = 0; i < length; i++)
 121                        dev_dbg(dev, "%s: test buf[%d]:0x%02x\n",
 122                                __func__, i, buf[i]);
 123
 124                return -EIO;
 125        }
 126
 127        return 0;
 128}
 129
 130static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
 131                                      u16 addr, u8 length, void *data)
 132{
 133        int rc;
 134
 135        rc = cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, NULL, 0);
 136        if (rc)
 137                return rc;
 138        else
 139                return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
 140                                length);
 141}
 142
 143static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
 144                                       u16 addr, u8 length, const void *data)
 145{
 146        return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
 147                        length);
 148}
 149
 150static const struct cyttsp4_bus_ops cyttsp_spi_bus_ops = {
 151        .bustype        = BUS_SPI,
 152        .write          = cyttsp_spi_write_block_data,
 153        .read           = cyttsp_spi_read_block_data,
 154};
 155
 156static int cyttsp4_spi_probe(struct spi_device *spi)
 157{
 158        struct cyttsp4 *ts;
 159        int error;
 160
 161        /* Set up SPI*/
 162        spi->bits_per_word = CY_SPI_BITS_PER_WORD;
 163        spi->mode = SPI_MODE_0;
 164        error = spi_setup(spi);
 165        if (error < 0) {
 166                dev_err(&spi->dev, "%s: SPI setup error %d\n",
 167                        __func__, error);
 168                return error;
 169        }
 170
 171        ts = cyttsp4_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
 172                          CY_SPI_DATA_BUF_SIZE);
 173
 174        return PTR_ERR_OR_ZERO(ts);
 175}
 176
 177static int cyttsp4_spi_remove(struct spi_device *spi)
 178{
 179        struct cyttsp4 *ts = spi_get_drvdata(spi);
 180        cyttsp4_remove(ts);
 181
 182        return 0;
 183}
 184
 185static struct spi_driver cyttsp4_spi_driver = {
 186        .driver = {
 187                .name   = CYTTSP4_SPI_NAME,
 188                .pm     = &cyttsp4_pm_ops,
 189        },
 190        .probe  = cyttsp4_spi_probe,
 191        .remove = cyttsp4_spi_remove,
 192};
 193
 194module_spi_driver(cyttsp4_spi_driver);
 195
 196MODULE_LICENSE("GPL");
 197MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
 198MODULE_AUTHOR("Cypress");
 199MODULE_ALIAS("spi:cyttsp4");
 200