Re: [PATCH v6 3/3] Input: cyttsp - add support for Cypress TTSP touchscreen SPI bus interface

On Tue, Oct 18, 2011 at 10:27 AM, Shubhrajyoti Datta
[off-list ref] wrote:

On Sun, Oct 16, 2011 at 12:07 AM, [off-list ref] wrote:

quoted

From: Javier Martinez Canillas <redacted>

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 <redacted>
---

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 |  295
+++++++++++++++++++++++++
 1 files changed, 295 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..66d6dc3

--- /dev/null
+++ b/drivers/input/touchscreen/cyttsp/cyttsp_spi.c

@@ -0,0 +1,295 @@
+/*
+ * 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) 2011 Javier Martinez Canillas

[off-list ref]
+ *
+ * Multi-touch protocol type B support and cleanups by Javier Martinez
Canillas
+ *
+ * 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 [off-list ref]
+ *
+ */
+
+#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
+        */
+

This is an empty function and could be removed?

Hi Shubhrajyoti,

Yes, I'll remove it and also fix the other issues called out by you
and resend the patch-set as v7.

Thanks a lot for the review and best regards,

-- 
Javier Martínez Canillas
(+34) 682 39 81 69
Barcelona, Spain
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