/*
 * Source for:
 * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
 * For use with Cypress Txx3xx parts.
 * Supported parts include:
 * CY8CTST341
 * CY8CTMA340
 *
 * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
 * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
 * Copyright (C) 2013 Cypress Semiconductor
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2, and only version 2, as published by the
 * Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com>
 *
 */

#include "cyttsp_core.h"

#include <linux/delay.h>
#include <linux/input.h>
#include <linux/spi/spi.h>

#define CY_SPI_WR_OP            0x00 /* r/~w */
#define CY_SPI_RD_OP            0x01
#define CY_SPI_CMD_BYTES        4
#define CY_SPI_SYNC_BYTE        2
#define CY_SPI_SYNC_ACK1        0x62 /* from protocol v.2 */
#define CY_SPI_SYNC_ACK2        0x9D /* from protocol v.2 */
#define CY_SPI_DATA_SIZE        128
#define CY_SPI_DATA_BUF_SIZE    (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
#define CY_SPI_BITS_PER_WORD    8

static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
                           u8 op, u16 reg, u8 *buf, int length)
{
        struct spi_device *spi = to_spi_device(dev);
        struct spi_message msg;
        struct spi_transfer xfer[2];
        u8 *wr_buf = &xfer_buf[0];
        u8 *rd_buf = &xfer_buf[CY_SPI_DATA_BUF_SIZE];
        int retval;
        int i;

        if (length > CY_SPI_DATA_SIZE) {
                dev_err(dev, "%s: length %d is too big.\n",
                        __func__, length);
                return -EINVAL;
        }

        memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE);
        memset(rd_buf, 0, CY_SPI_DATA_BUF_SIZE);

        wr_buf[0] = 0x00; /* header byte 0 */
        wr_buf[1] = 0xFF; /* header byte 1 */
        wr_buf[2] = reg;  /* reg index */
        wr_buf[3] = op;   /* r/~w */
        if (op == CY_SPI_WR_OP)
                memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);

        memset(xfer, 0, sizeof(xfer));
        spi_message_init(&msg);

        /*
          We set both TX and RX buffers because Cypress TTSP
          requires full duplex operation.
        */
        xfer[0].tx_buf = wr_buf;
        xfer[0].rx_buf = rd_buf;
        switch (op) {
        case CY_SPI_WR_OP:
                xfer[0].len = length + CY_SPI_CMD_BYTES;
                spi_message_add_tail(&xfer[0], &msg);
                break;

        case CY_SPI_RD_OP:
                xfer[0].len = CY_SPI_CMD_BYTES;
                spi_message_add_tail(&xfer[0], &msg);

                xfer[1].rx_buf = buf;
                xfer[1].len = length;
                spi_message_add_tail(&xfer[1], &msg);
                break;

        default:
                dev_err(dev, "%s: bad operation code=%d\n", __func__, op);
                return -EINVAL;
        }

        retval = spi_sync(spi, &msg);
        if (retval < 0) {
                dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n",
                        __func__, retval, xfer[1].len, op);

                /*
                 * do not return here since was a bad ACK sequence
                 * let the following ACK check handle any errors and
                 * allow silent retries
                 */
        }

        if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK1 ||
            rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) {
                dev_dbg(dev, "%s: operation %d failed\n", __func__, op);

                for (i = 0; i < CY_SPI_CMD_BYTES; i++)
                        dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n",
                                __func__, i, rd_buf[i]);
                for (i = 0; i < length; i++)
                        dev_dbg(dev, "%s: test buf[%d]:0x%02x\n",
                                __func__, i, buf[i]);

                return -EIO;
        }

        return 0;
}

static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
                                      u16 addr, u8 length, void *data)
{
        return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
                        length);
}

static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
                                       u16 addr, u8 length, const void *data)
{
        return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
                        length);
}

static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = {
        .bustype        = BUS_SPI,
        .write          = cyttsp_spi_write_block_data,
        .read           = cyttsp_spi_read_block_data,
};

static int cyttsp_spi_probe(struct spi_device *spi)
{
        struct cyttsp *ts;
        int error;

        /* Set up SPI*/
        spi->bits_per_word = CY_SPI_BITS_PER_WORD;
        spi->mode = SPI_MODE_0;
        error = spi_setup(spi);
        if (error < 0) {
                dev_err(&spi->dev, "%s: SPI setup error %d\n",
                        __func__, error);
                return error;
        }

        ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
                          CY_SPI_DATA_BUF_SIZE * 2);
        if (IS_ERR(ts))
                return PTR_ERR(ts);

        spi_set_drvdata(spi, ts);

        return 0;
}

static int cyttsp_spi_remove(struct spi_device *spi)
{
        struct cyttsp *ts = spi_get_drvdata(spi);

        cyttsp_remove(ts);

        return 0;
}

static struct spi_driver cyttsp_spi_driver = {
        .driver = {
                .name   = CY_SPI_NAME,
                .owner  = THIS_MODULE,
                .pm     = &cyttsp_pm_ops,
        },
        .probe  = cyttsp_spi_probe,
        .remove = cyttsp_spi_remove,
};

module_spi_driver(cyttsp_spi_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
MODULE_AUTHOR("Cypress");
MODULE_ALIAS("spi:cyttsp");