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Date: Fri, 22 Feb 2013 17:57:54 +0000
From: Nick Dyer <nick.dyer@...ev.co.uk>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Daniel Kurtz <djkurtz@...omium.org>,
Henrik Rydberg <rydberg@...omail.se>,
Joonyoung Shim <jy0922.shim@...sung.com>,
Alan.Bowens@...el.com, linux-input@...r.kernel.org,
linux-kernel@...r.kernel.org, pmeerw@...erw.net,
bleung@...omium.org, olofj@...omium.org
Cc: Nick Dyer <nick.dyer@...ev.co.uk>
Subject: [PATCH 07/40] Input: atmel_mxt_ts - Implement CRC check for configuration data.
The configuration is stored in NVRAM on the maXTouch chip. When the device is
reset it reports a CRC of the stored configuration values. Therefore it isn't
necessary to send the configuration on each probe - we can check the CRC
matches and avoid a timeconsuming backup/reset cycle.
Signed-off-by: Nick Dyer <nick.dyer@...ev.co.uk>
---
drivers/input/touchscreen/atmel_mxt_ts.c | 61 ++++++++++++++++++++++++------
include/linux/i2c/atmel_mxt_ts.h | 1 +
2 files changed, 51 insertions(+), 11 deletions(-)
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index fa294d1..6f30713 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -261,6 +261,7 @@ struct mxt_data {
unsigned int max_y;
struct bin_attribute mem_access_attr;
bool debug_enabled;
+ u32 config_crc;
/* Cached parameters from object table */
u8 T6_reportid;
@@ -528,6 +529,10 @@ static void mxt_input_touchevent(struct mxt_data *data,
int area;
int pressure;
+ /* do not report events if input device not yet registered */
+ if (!input_dev)
+ return;
+
x = (message->message[1] << 4) | ((message->message[3] >> 4) & 0xf);
y = (message->message[2] << 4) | ((message->message[3] & 0xf));
if (data->max_x < 1024)
@@ -563,7 +568,7 @@ static void mxt_input_touchevent(struct mxt_data *data,
}
}
-static unsigned mxt_extract_T6_csum(const u8 *csum)
+static u16 mxt_extract_T6_csum(const u8 *csum)
{
return csum[0] | (csum[1] << 8) | (csum[2] << 16);
}
@@ -574,9 +579,8 @@ static bool mxt_is_T9_message(struct mxt_data *data, struct mxt_message *msg)
return (id >= data->T9_reportid_min && id <= data->T9_reportid_max);
}
-static irqreturn_t mxt_interrupt(int irq, void *dev_id)
+static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data)
{
- struct mxt_data *data = dev_id;
struct mxt_message message;
const u8 *payload = &message.message[0];
struct device *dev = &data->client->dev;
@@ -587,7 +591,7 @@ static irqreturn_t mxt_interrupt(int irq, void *dev_id)
do {
if (mxt_read_message(data, &message)) {
dev_err(dev, "Failed to read message\n");
- goto end;
+ return IRQ_NONE;
}
reportid = message.reportid;
@@ -595,9 +599,9 @@ static irqreturn_t mxt_interrupt(int irq, void *dev_id)
if (reportid == data->T6_reportid) {
u8 status = payload[0];
- unsigned csum = mxt_extract_T6_csum(&payload[1]);
+ data->config_crc = mxt_extract_T6_csum(&payload[1]);
dev_dbg(dev, "Status: %02x Config Checksum: %06x\n",
- status, csum);
+ status, data->config_crc);
handled = true;
} else if (mxt_is_T9_message(data, &message)) {
int id = reportid - data->T9_reportid_min;
@@ -615,10 +619,16 @@ static irqreturn_t mxt_interrupt(int irq, void *dev_id)
input_sync(data->input_dev);
}
-end:
return IRQ_HANDLED;
}
+static irqreturn_t mxt_interrupt(int irq, void *dev_id)
+{
+ struct mxt_data *data = dev_id;
+
+ return mxt_process_messages_until_invalid(data);
+}
+
static int mxt_t6_command(struct mxt_data *data, u16 cmd_offset, u8 value, bool wait)
{
u16 reg;
@@ -679,6 +689,19 @@ static int mxt_soft_reset(struct mxt_data *data, u8 value)
return 0;
}
+static void mxt_read_current_crc(struct mxt_data *data)
+{
+ /* on failure, CRC is set to 0 and config will always be downloaded */
+ data->config_crc = 0;
+
+ mxt_t6_command(data, MXT_COMMAND_REPORTALL, 1, true);
+
+ /* Read all messages until invalid, this will update the config crc
+ * stored in mxt_data. On failure, CRC is set to 0 and config will
+ * always be downloaded */
+ mxt_process_messages_until_invalid(data);
+}
+
static int mxt_check_reg_init(struct mxt_data *data)
{
const struct mxt_platform_data *pdata = data->pdata;
@@ -693,6 +716,16 @@ static int mxt_check_reg_init(struct mxt_data *data)
return 0;
}
+ mxt_read_current_crc(data);
+
+ if (data->config_crc == pdata->config_crc) {
+ dev_info(dev, "Config CRC 0x%06X: OK\n", data->config_crc);
+ return 0;
+ } else {
+ dev_info(dev, "Config CRC 0x%06X: does not match 0x%06X\n",
+ data->config_crc, pdata->config_crc);
+ }
+
for (i = 0; i < data->info.object_num; i++) {
object = data->object_table + i;
@@ -712,6 +745,16 @@ static int mxt_check_reg_init(struct mxt_data *data)
index += size;
}
+ ret = mxt_t6_command(data, MXT_COMMAND_BACKUPNV, MXT_BACKUP_VALUE, false);
+ if (ret)
+ return ret;
+
+ ret = mxt_soft_reset(data, MXT_RESET_VALUE);
+ if (ret)
+ return ret;
+
+ dev_info(dev, "Config written\n");
+
return 0;
}
@@ -855,10 +898,6 @@ static int mxt_initialize(struct mxt_data *data)
return error;
}
- error = mxt_t6_command(data, MXT_COMMAND_BACKUPNV, MXT_BACKUP_VALUE, false);
- if (!error)
- mxt_soft_reset(data, MXT_RESET_VALUE);
-
/* Update matrix size at info struct */
error = mxt_read_reg(client, MXT_MATRIX_X_SIZE, &val);
if (error)
diff --git a/include/linux/i2c/atmel_mxt_ts.h b/include/linux/i2c/atmel_mxt_ts.h
index 6a879a6..1d5a664 100644
--- a/include/linux/i2c/atmel_mxt_ts.h
+++ b/include/linux/i2c/atmel_mxt_ts.h
@@ -29,6 +29,7 @@
struct mxt_platform_data {
const u8 *config;
size_t config_length;
+ u32 config_crc;
unsigned int x_size;
unsigned int y_size;
--
1.7.10.4
--
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