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    Subject[PATCH v8 3/3] Input: cyttsp - add support for Cypress TTSP touchscreen SPI bus interface
    Date
    The driver is composed of a core driver that process the data sent by
    the contacts and a set of bus specific interface modules.

    This patch add supports for the Cypress TTSP SPI bus interface.

    Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
    ---

    Changes for v8:
    Javier Martinez Canillas (2):
    - struct cyttsp is inside struct device not struct spi_device
    - Add error msg when capability is not supported

    Kevin McNeely (1):
    - SPI xfer function cleanups

    drivers/input/touchscreen/cyttsp_spi.c | 245 ++++++++++++++++++++++++++++++++
    1 files changed, 245 insertions(+), 0 deletions(-)
    create mode 100644 drivers/input/touchscreen/cyttsp_spi.c

    diff --git a/drivers/input/touchscreen/cyttsp_spi.c b/drivers/input/touchscreen/cyttsp_spi.c
    new file mode 100644
    index 0000000..3238c7d
    --- /dev/null
    +++ b/drivers/input/touchscreen/cyttsp_spi.c
    @@ -0,0 +1,245 @@
    +/*
    + * 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>
    + *
    + * 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.
    + *
    + * You should have received a copy of the GNU General Public License along
    + * with this program; if not, write to the Free Software Foundation, Inc.,
    + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
    + *
    + * Contact Cypress Semiconductor at www.cypress.com <kev@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(u8 op, struct spi_device *spi,
    + u8 reg, u8 *buf, int length)
    +{
    + struct cyttsp *ts = spi_get_drvdata(spi);
    + struct spi_message msg;
    + struct spi_transfer xfer[2];
    + u8 *wr_buf = &ts->xfer_buf[0];
    + u8 *rd_buf = &ts->xfer_buf[CY_SPI_DATA_BUF_SIZE];
    + int retval;
    +
    + if (length > CY_SPI_DATA_SIZE) {
    + dev_dbg(&spi->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_dbg(&spi->dev,
    + "%s: bad operation code=%d\n", __func__, op);
    + return -EINVAL;
    + }
    +
    + retval = spi_sync(spi, &msg);
    + if (retval < 0) {
    + dev_dbg(&spi->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) {
    + int i;
    + for (i = 0; i < CY_SPI_CMD_BYTES; i++)
    + dev_dbg(&spi->dev,
    + "%s: test rd_buf[%d]:0x%02x\n",
    + __func__, i, rd_buf[i]);
    + for (i = 0; i < length; i++)
    + dev_dbg(&spi->dev,
    + "%s: test buf[%d]:0x%02x\n",
    + __func__, i, buf[i]);
    +
    + /* signal ACK error so silent retry */
    + return 1;
    + }
    +
    + return 0;
    +}
    +
    +static int cyttsp_spi_read_block_data(struct device *dev,
    + u8 addr, u8 length, void *data)
    +{
    + struct spi_device *spi = to_spi_device(dev);
    + int retval;
    +
    + retval = cyttsp_spi_xfer(CY_SPI_RD_OP, spi, addr, data, length);
    + if (retval < 0)
    + dev_err(dev, "cyttsp_spi_read_block_data failed, err: %d\n",
    + retval);
    +
    + /*
    + * Do not print the above error if the data sync bytes were not found.
    + * This is a normal condition for the bootloader loader startup and need
    + * to retry until data sync bytes are found.
    + */
    + if (retval > 0)
    + retval = -EIO; /* now signal fail; so retry can be done */
    +
    + return retval;
    +}
    +
    +static int cyttsp_spi_write_block_data(struct device *dev,
    + u8 addr, u8 length, const void *data)
    +{
    + struct spi_device *spi = to_spi_device(dev);
    + int retval;
    +
    + retval = cyttsp_spi_xfer(CY_SPI_WR_OP, spi, addr, (void *)data, length);
    + if (retval < 0)
    + dev_err(dev, "cyttsp_spi_write_block_data failed, err: %d\n",
    + retval);
    +
    + /*
    + * Do not print the above error if the data sync bytes were not found.
    + * This is a normal condition for the bootloader loader startup and need
    + * to retry until data sync bytes are found.
    + */
    + if (retval > 0)
    + retval = -EIO; /* now signal fail; so retry can be done */
    +
    + return retval;
    +}
    +
    +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 __devinit 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 __devexit cyttsp_spi_remove(struct spi_device *spi)
    +{
    + struct cyttsp *ts = dev_get_drvdata(&spi->dev);
    +
    + 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 = __devexit_p(cyttsp_spi_remove),
    +};
    +
    +static int __init cyttsp_spi_init(void)
    +{
    + return spi_register_driver(&cyttsp_spi_driver);
    +}
    +module_init(cyttsp_spi_init);
    +
    +static void __exit cyttsp_spi_exit(void)
    +{
    + spi_unregister_driver(&cyttsp_spi_driver);
    +}
    +module_exit(cyttsp_spi_exit);
    +
    +MODULE_ALIAS("spi:cyttsp");
    +MODULE_LICENSE("GPL");
    +MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
    +MODULE_AUTHOR("Cypress");
    +MODULE_ALIAS("spi:cyttsp");
    +
    --
    1.7.4.1


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