[PATCH v8 3/3] Input: cyttsp - add support for Cypress TTSP touchscreen SPI bus interface

[Javier Martinez Canillas]

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@xxxxxxxxxxxx>
---

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@xxxxxxxxxxxx>
+ *
+ * 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@xxxxxxxxxxx>
+ *
+ */
+
+#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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