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Subject[PATCH V3 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.

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


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