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

Bastien Nocera
2016-10-27T13:54:25Z

On Sat, 2016-09-10 at 20:57 +0300, Irina Tirdea wrote:
> 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.

Reviewed-by: Bastien Nocera <hadess@hadess.net>

Only thing I don't like is the overly complicated bash script. I'd
really rather the code was in C, making it easier to debug, and not
rely on a fair number of external utilities.

>
> 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;
>  }