[PATCH v12 1/5] Input: goodix - add sysfs interface to dump config

Irina Tirdea
2016-09-10T17:58:49Z

Goodix devices have a configuration information register area that
specifies various parameters for the device. The configuration information
has a specific format described in the Goodix datasheet. It includes X/Y
resolution, maximum supported touch points, interrupt flags, various
sesitivity factors and settings for advanced features (like gesture
recognition).

Export a sysfs interface that would allow reading the configuration
information. The default device configuration can be used as a starting
point for creating a valid configuration firmware used by the device at
init time to update its configuration.

This sysfs interface will be exported only if the gpio pins are properly
initialized from ACPI/DT.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
Documentation/input/goodix.txt | 84 ++++++++++++++++++++++++++++++++++++++
drivers/input/touchscreen/goodix.c | 64 ++++++++++++++++++++++++++---
2 files changed, 143 insertions(+), 5 deletions(-)
create mode 100644 Documentation/input/goodix.txt

diff --git a/Documentation/input/goodix.txt b/Documentation/input/goodix.txt
new file mode 100644
index 0000000..f9be1e2
--- /dev/null
+++ b/Documentation/input/goodix.txt
@@ -0,0 +1,84 @@
+Goodix touchscreen driver
+=====================================
+
+How to update configuration firmware
+=====================================
+
+Goodix touchscreen devices have a set of registers that specify configuration
+information for the device. The configuration information has a specific format
+described in the Goodix datasheet. It includes X/Y resolution, maximum
+supported touch points, interrupt flags, various sesitivity factors and
+settings for advanced features (like gesture recognition).
+
+The devices have an initial default configuration that can be read through
+the sysfs interface (/sys/class/input/inputX/device/dump_config). This default
+configuration can be used as a starting point for creating a new configuration
+firmware file. At init, the driver will read the configuration firmware file
+and update the device configuration.
+
+This configuration can be accesed only if both interrupt and reset gpio pins
+are connected and properly configured through ACPI _DSD/DT properties.
+
+Below are instructions on how to generate a valid configuration starting from
+the device default configuration.
+
+1. Dump the default configuration of the device to a file:
+ $ cat /sys/class/input/inputX/device/dump_config > goodix_<model>_cfg
+
+2. Make the needed changes to the configuration (e.g. change resolution of
+x/y axes, maximum reported touch points, switch X,Y axes, etc.). For more
+details check the Goodix datasheet for format of Configuration Registers.
+
+3. Generate a valid configuration starting from goodix_<model>_cfg.
+After making changes, you need to recompute the checksum of the entire
+configuration data, set Config_Fresh to 1 and generate the binary config
+firmware image. This can be done using a helper script similar to the
+one below:
+
+#!/bin/bash
+
+if [[ $# -lt 1 ]]; then
+ echo "$0 fw_filename"
+ exit 1
+fi
+
+file_in="$1"
+file_out_bin=${file_in}.bin
+
+print_val ()
+{
+ val="$1"
+ printf "0x%.2x" "$val" | xxd -r -p >> ${file_out_bin}
+}
+
+rm -f ${file_out_bin}
+
+size=`cat ${file_in} | wc -w`
+
+checksum=0
+i=1
+for val in `cat ${file_in}`; do
+ val="0x$val"
+ if [[ $i == $size ]]; then
+ # Config_Fresh
+ print_val 0x01
+ elif [[ $i == $((size-1)) ]]; then
+ # Config_Chksum
+ checksum=$(( (~ checksum + 1) & 0xFF))
+ print_val $checksum
+ else
+ checksum=$((checksum + val))
+ print_val $val
+ fi
+ i=$((i+1))
+done
+
+echo "Wrote ${file_out_bin}"
+
+4. Copy the binary config firmware in the appropriate location
+(e.g. /lib/firmware), using the name goodix_<model>_cfg.bin (e.g. for gt911,
+use goodix_911_cfg.bin).
+
+5. Check that the new firmware was successfully written to the device
+after reboot. Config_Fresh is reset to 0 after a successful update of the
+configuration.
diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
index 240b16f..2447b73 100644
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -430,6 +430,40 @@ static int goodix_reset(struct goodix_ts_data *ts)
return 0;
}

+static ssize_t goodix_dump_config_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct goodix_ts_data *ts = dev_get_drvdata(dev);
+ u8 config[GOODIX_CONFIG_MAX_LENGTH];
+ int error, count = 0, i;
+
+ wait_for_completion(&ts->firmware_loading_complete);
+
+ error = goodix_i2c_read(ts->client, GOODIX_REG_CONFIG_DATA,
+ config, ts->cfg_len);
+ if (error) {
+ dev_warn(&ts->client->dev,
+ "Error reading config (%d)\n", error);
+ return error;
+ }
+
+ for (i = 0; i < ts->cfg_len; i++)
+ count += scnprintf(buf + count, PAGE_SIZE - count, "%02x ",
+ config[i]);
+ return count;
+}
+
+static DEVICE_ATTR(dump_config, S_IRUGO, goodix_dump_config_show, NULL);
+
+static struct attribute *goodix_attrs[] = {
+ &dev_attr_dump_config.attr,
+ NULL
+};
+
+static const struct attribute_group goodix_attr_group = {
+ .attrs = goodix_attrs,
+};
+
/**
* goodix_get_gpio_config - Get GPIO config from ACPI/DT
*
@@ -735,11 +769,22 @@ static int goodix_ts_probe(struct i2c_client *client,
ts->cfg_len = goodix_get_cfg_len(ts->id);

if (ts->gpiod_int && ts->gpiod_rst) {
+ error = sysfs_create_group(&client->dev.kobj,
+ &goodix_attr_group);
+ if (error) {
+ dev_err(&client->dev,
+ "Failed to create sysfs group: %d\n",
+ error);
+ return error;
+ }
+
/* update device config */
ts->cfg_name = devm_kasprintf(&client->dev, GFP_KERNEL,
"goodix_%d_cfg.bin", ts->id);
- if (!ts->cfg_name)
- return -ENOMEM;
+ if (!ts->cfg_name) {
+ error = -ENOMEM;
+ goto err_sysfs_remove_group;
+ }

error = request_firmware_nowait(THIS_MODULE, true, ts->cfg_name,
&client->dev, GFP_KERNEL, ts,
@@ -748,7 +793,7 @@ static int goodix_ts_probe(struct i2c_client *client,
dev_err(&client->dev,
"Failed to invoke firmware loader: %d\n",
error);
- return error;
+ goto err_sysfs_remove_group;
}

return 0;
@@ -759,14 +804,23 @@ static int goodix_ts_probe(struct i2c_client *client,
}

return 0;
+
+err_sysfs_remove_group:
+ if (ts->gpiod_int && ts->gpiod_rst)
+ sysfs_remove_group(&client->dev.kobj, &goodix_attr_group);
+ return error;
}

static int goodix_ts_remove(struct i2c_client *client)
{
struct goodix_ts_data *ts = i2c_get_clientdata(client);

- if (ts->gpiod_int && ts->gpiod_rst)
- wait_for_completion(&ts->firmware_loading_complete);
+ if (!ts->gpiod_int || !ts->gpiod_rst)
+ return 0;
+
+ wait_for_completion(&ts->firmware_loading_complete);
+
+ sysfs_remove_group(&client->dev.kobj, &goodix_attr_group);

return 0;
}
--
1.9.1