[PATCH V3 3/3] Input: cyttsp - add support for Cypress TTSP touchscreen SPI bus interface

[Javier Martinez Canillas <martinez.javier@gmail.com>]

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.

The original author of the driver is Kevin McNeely <kev@cypress.com>

Signed-off-by: Javier Martinez Canillas <martinez.javier@gmail.com>
---
V2: Fix issues called out by Dmitry Torokhov
	- Extract the IRQ from the spi client data and pass to cyttsp_core_init
	- Remove the extra retries and limit the retries to the cyttsp_core.c
	  read/write block functions.
	- Cleanup cyttsp_spi_xfer(), check ACK in write operation and fix special
	  EIO case to show its meaning.

V3: Fix issues called out by Henrik Rydberg and Mohan Pallaka
    - Remove bus type info since it is not used

 drivers/input/touchscreen/cyttsp/cyttsp_spi.c |  292 +++++++++++++++++++++++++
 1 files changed, 292 insertions(+), 0 deletions(-)
 create mode 100644 drivers/input/touchscreen/cyttsp/cyttsp_spi.c

diff --git a/drivers/input/touchscreen/cyttsp/cyttsp_spi.c b/drivers/input/touchscreen/cyttsp/cyttsp_spi.c
new file mode 100644
index 0000000..5567859
--- /dev/null
+++ b/drivers/input/touchscreen/cyttsp/cyttsp_spi.c
@@ -0,0 +1,292 @@
+/*
+ * 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.
+ *
+ * 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/spi/spi.h>
+#include <linux/delay.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
+
+struct cyttsp_spi {
+	struct cyttsp_bus_ops bus_ops;
+	struct spi_device *spi_client;
+	void *ttsp_client;
+	u8 wr_buf[CY_SPI_DATA_BUF_SIZE];
+	u8 rd_buf[CY_SPI_DATA_BUF_SIZE];
+};
+
+static int cyttsp_spi_xfer(u8 op, struct cyttsp_spi *ts,
+			   u8 reg, u8 *buf, int length)
+{
+	struct spi_message msg;
+	struct spi_transfer xfer[2];
+	u8 *wr_buf = ts->wr_buf;
+	u8 *rd_buf = ts->rd_buf;
+	int retval;
+
+	if (length > CY_SPI_DATA_SIZE) {
+		dev_dbg(ts->bus_ops.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((void *)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;
+	if (op == CY_SPI_WR_OP) {
+		xfer[0].len = length + CY_SPI_CMD_BYTES;
+		spi_message_add_tail(&xfer[0], &msg);
+	} else if (op == 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);
+	}
+
+	retval = spi_sync(ts->spi_client, &msg);
+	if (retval < 0) {
+		dev_dbg(ts->bus_ops.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))
+		retval = 0;
+	else {
+		int i;
+		for (i = 0; i < (CY_SPI_CMD_BYTES); i++)
+			dev_dbg(ts->bus_ops.dev,
+				"%s: test rd_buf[%d]:0x%02x\n",
+				__func__, i, rd_buf[i]);
+		for (i = 0; i < (length); i++)
+			dev_dbg(ts->bus_ops.dev,
+				"%s: test buf[%d]:0x%02x\n",
+				__func__, i, buf[i]);
+
+		/* signal ACK error so silent retry */
+		retval = 1;
+	}
+
+	return retval;
+}
+
+static s32 ttsp_spi_read_block_data(void *handle, u8 addr,
+				    u8 length, void *data)
+{
+	struct cyttsp_spi *ts =
+		container_of(handle, struct cyttsp_spi, bus_ops);
+	int retval;
+
+	retval = cyttsp_spi_xfer(CY_SPI_RD_OP, ts, addr, data, length);
+	if (retval < 0)
+		pr_err("%s: ttsp_spi_read_block_data failed\n",
+		       __func__);
+
+	/*
+	 * 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 s32 ttsp_spi_write_block_data(void *handle, u8 addr,
+				     u8 length, const void *data)
+{
+	struct cyttsp_spi *ts =
+		container_of(handle, struct cyttsp_spi, bus_ops);
+	int retval;
+
+	retval = cyttsp_spi_xfer(CY_SPI_WR_OP, ts, addr, (void *)data, length);
+	if (retval < 0)
+		pr_err("%s: ttsp_spi_write_block_data failed\n",
+		       __func__);
+
+	/*
+	 * 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 s32 ttsp_spi_tch_ext(void *handle, void *values)
+{
+	struct cyttsp_spi *ts =
+		container_of(handle, struct cyttsp_spi, bus_ops);
+	int retval = 0;
+
+	/*
+	 * TODO: Add custom touch extension handling code here
+	 * set: retval < 0 for any returned system errors,
+	 *	retval = 0 if normal touch handling is required,
+	 *	retval > 0 if normal touch handling is *not* required
+	 */
+
+	if (!ts || !values)
+		retval = -EINVAL;
+
+	return retval;
+}
+
+static int __devinit cyttsp_spi_probe(struct spi_device *spi)
+{
+	struct cyttsp_spi *ts;
+	int retval;
+
+	/* Set up SPI*/
+	spi->bits_per_word = CY_SPI_BITS_PER_WORD;
+	spi->mode = SPI_MODE_0;
+	retval = spi_setup(spi);
+	if (retval < 0) {
+		dev_dbg(&spi->dev, "%s: SPI setup error %d\n",
+			__func__, retval);
+		return retval;
+	}
+
+	ts = kzalloc(sizeof(*ts), GFP_KERNEL);
+	if (!ts) {
+		dev_dbg(&spi->dev, "%s: Error, kzalloc\n", __func__);
+		return -ENOMEM;
+	}
+
+	ts->spi_client = spi;
+	dev_set_drvdata(&spi->dev, ts);
+	ts->bus_ops.write = ttsp_spi_write_block_data;
+	ts->bus_ops.read = ttsp_spi_read_block_data;
+	ts->bus_ops.ext = ttsp_spi_tch_ext;
+	ts->bus_ops.dev = &spi->dev;
+
+	ts->ttsp_client = cyttsp_core_init(&ts->bus_ops, &spi->dev, spi->irq);
+	if (IS_ERR(ts->ttsp_client)) {
+		int retval = PTR_ERR(ts->ttsp_client);
+		kfree(ts);
+		return retval;
+	}
+
+	dev_dbg(ts->bus_ops.dev, "%s: Registration complete\n", __func__);
+
+	return 0;
+}
+
+static int __devexit cyttsp_spi_remove(struct spi_device *spi)
+{
+	struct cyttsp_spi *ts = dev_get_drvdata(&spi->dev);
+
+	cyttsp_core_release(ts->ttsp_client);
+	kfree(ts);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int cyttsp_spi_suspend(struct spi_device *spi, pm_message_t message)
+{
+	struct cyttsp_spi *ts = dev_get_drvdata(&spi->dev);
+
+	return cyttsp_suspend(ts->ttsp_client);
+}
+
+static int cyttsp_spi_resume(struct spi_device *spi)
+{
+	struct cyttsp_spi *ts = dev_get_drvdata(&spi->dev);
+
+	return cyttsp_resume(ts->ttsp_client);
+}
+#endif
+
+static struct spi_driver cyttsp_spi_driver = {
+	.driver = {
+		.name = CY_SPI_NAME,
+		.owner = THIS_MODULE,
+	},
+	.probe = cyttsp_spi_probe,
+	.remove = __devexit_p(cyttsp_spi_remove),
+#ifdef CONFIG_PM
+	.suspend = cyttsp_spi_suspend,
+	.resume = cyttsp_spi_resume,
+#endif
+};
+
+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");
+
-- 
1.7.4.1