Hi Sebastian,
On 20/5/20 17:39, Sebastian Reichel wrote:
> Expose model and fw_version via sysfs. Also query the model
> in probe to make sure, that the I2C communication with the
> device works before successfully probing the driver.
>
> This is a bit complicated, since EETI devices do not have
> a sync interface. Sending the commands and directly reading
> does not work. Sending the command and waiting for some time
> is also not an option, since there might be touch events in
> the mean time.
>
> Last but not least we do not cache the results, since this
> interface can be used to check the I2C communication is still
> working as expected.
>
> Signed-off-by: Sebastian Reichel <sebastian.reic...@collabora.com>
I went through the code and understood the reasoning to implement that way, if
it helps:
Reviewed-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
> ---
> .../ABI/testing/sysfs-driver-input-exc3000 | 15 ++
> drivers/input/touchscreen/exc3000.c | 145 +++++++++++++++++-
> 2 files changed, 159 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/ABI/testing/sysfs-driver-input-exc3000
>
> diff --git a/Documentation/ABI/testing/sysfs-driver-input-exc3000
> b/Documentation/ABI/testing/sysfs-driver-input-exc3000
> new file mode 100644
> index 000000000000..d79da4f869af
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-input-exc3000
> @@ -0,0 +1,15 @@
> +What: /sys/class/input/inputX/fw_version
> +Date: May 2020
> +Contact: linux-in...@vger.kernel.org
> +Description: Reports the firmware version provided by the touchscreen, for
> example "00_T6" on a EXC80H60
> +
> + Access: Read
> + Valid values: Represented as string
> +
> +What: /sys/class/input/inputX/model
> +Date: May 2020
> +Contact: linux-in...@vger.kernel.org
> +Description: Reports the model identification provided by the touchscreen,
> for example "Orion_1320" on a EXC80H60
> +
> + Access: Read
> + Valid values: Represented as string
> diff --git a/drivers/input/touchscreen/exc3000.c
> b/drivers/input/touchscreen/exc3000.c
> index b497bd2ae41d..b5a3bbb63504 100644
> --- a/drivers/input/touchscreen/exc3000.c
> +++ b/drivers/input/touchscreen/exc3000.c
> @@ -25,6 +25,9 @@
> #define EXC3000_LEN_FRAME 66
> #define EXC3000_LEN_POINT 10
>
> +#define EXC3000_LEN_MODEL_NAME 16
> +#define EXC3000_LEN_FW_VERSION 16
> +
> #define EXC3000_MT1_EVENT 0x06
> #define EXC3000_MT2_EVENT 0x18
>
> @@ -65,6 +68,11 @@ struct exc3000_data {
> struct touchscreen_properties prop;
> struct timer_list timer;
> u8 buf[2 * EXC3000_LEN_FRAME];
> + struct completion wait_event;
> + struct mutex query_lock;
> + int query_result;
> + char model[EXC3000_LEN_MODEL_NAME];
> + char fw_version[EXC3000_LEN_FW_VERSION];
> };
>
> static void exc3000_report_slots(struct input_dev *input,
> @@ -150,6 +158,28 @@ static int exc3000_read_data(struct exc3000_data *data,
> return 0;
> }
>
> +static int exc3000_query_interrupt(struct exc3000_data *data)
> +{
> + u8 *buf = data->buf;
> + int err;
> +
> + err = i2c_master_recv(data->client, buf, EXC3000_LEN_FRAME);
> + if (err < 0)
> + return err;
> +
> + if (buf[0] != 0x42)
> + return -EPROTO;
> +
> + if (buf[4] == 'E')
> + strlcpy(data->model, buf+5, sizeof(data->model));
> + else if (buf[4] == 'D')
> + strlcpy(data->fw_version, buf+5, sizeof(data->fw_version));
> + else
> + return -EPROTO;
> +
> + return 0;
> +}
> +
> static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
> {
> struct exc3000_data *data = dev_id;
> @@ -158,6 +188,12 @@ static irqreturn_t exc3000_interrupt(int irq, void
> *dev_id)
> int slots, total_slots;
> int error;
>
> + if (mutex_is_locked(&data->query_lock)) {
> + data->query_result = exc3000_query_interrupt(data);
> + complete(&data->wait_event);
> + goto out;
> + }
> +
> error = exc3000_read_data(data, buf, &total_slots);
> if (error) {
> /* Schedule a timer to release "stuck" contacts */
> @@ -185,11 +221,94 @@ static irqreturn_t exc3000_interrupt(int irq, void
> *dev_id)
> return IRQ_HANDLED;
> }
>
> +static ssize_t fw_version_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct exc3000_data *data = dev_get_drvdata(dev);
> + static const u8 request[68] = {
> + 0x67, 0x00, 0x42, 0x00, 0x03, 0x01, 'D', 0x00
> + };
> + struct i2c_client *client = data->client;
> + int err;
> +
> + mutex_lock(&data->query_lock);
> +
> + data->query_result = -ETIMEDOUT;
> + reinit_completion(&data->wait_event);
> +
> + err = i2c_master_send(client, request, sizeof(request));
> + if (err < 0) {
> + mutex_unlock(&data->query_lock);
> + return err;
> + }
> +
> + wait_for_completion_interruptible_timeout(&data->wait_event, 1*HZ);
> + mutex_unlock(&data->query_lock);
> +
> + if (data->query_result < 0)
> + return data->query_result;
> +
> + return sprintf(buf, "%s\n", data->fw_version);
> +}
> +static DEVICE_ATTR_RO(fw_version);
> +
> +static ssize_t exc3000_get_model(struct exc3000_data *data)
> +{
> + static const u8 request[68] = {
> + 0x67, 0x00, 0x42, 0x00, 0x03, 0x01, 'E', 0x00
> + };
> + struct i2c_client *client = data->client;
> + int err;
> +
> + mutex_lock(&data->query_lock);
> + data->query_result = -ETIMEDOUT;
> + reinit_completion(&data->wait_event);
> +
> + err = i2c_master_send(client, request, sizeof(request));
> + if (err < 0) {
> + mutex_unlock(&data->query_lock);
> + return err;
> + }
> +
> + wait_for_completion_interruptible_timeout(&data->wait_event, 1 * HZ);
> + mutex_unlock(&data->query_lock);
> +
> + return data->query_result;
> +}
> +
> +static ssize_t model_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct exc3000_data *data = dev_get_drvdata(dev);
> + int err = exc3000_get_model(data);
> +
> + if (err < 0)
> + return err;
> +
> + return sprintf(buf, "%s\n", data->model);
> +}
> +static DEVICE_ATTR_RO(model);
> +
> +static struct attribute *sysfs_attrs[] = {
> + &dev_attr_fw_version.attr,
> + &dev_attr_model.attr,
> + NULL
> +};
> +
> +static struct attribute_group exc3000_attribute_group = {
> + .attrs = sysfs_attrs
> +};
> +
> +static const struct attribute_group *exc3000_attribute_groups[] = {
> + &exc3000_attribute_group,
> + NULL
> +};
> +
> static int exc3000_probe(struct i2c_client *client)
> {
> struct exc3000_data *data;
> struct input_dev *input;
> - int error, max_xy;
> + int error, max_xy, retry;
>
> data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
> if (!data)
> @@ -203,15 +322,19 @@ static int exc3000_probe(struct i2c_client *client)
> data->info = &exc3000_info[eeti_dev_id];
> }
> timer_setup(&data->timer, exc3000_timer, 0);
> + init_completion(&data->wait_event);
> + mutex_init(&data->query_lock);
>
> input = devm_input_allocate_device(&client->dev);
> if (!input)
> return -ENOMEM;
>
> data->input = input;
> + input_set_drvdata(input, data);
>
> input->name = data->info->name;
> input->id.bustype = BUS_I2C;
> + input->dev.groups = exc3000_attribute_groups;
>
> max_xy = data->info->max_xy;
> input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
> @@ -234,6 +357,26 @@ static int exc3000_probe(struct i2c_client *client)
> if (error)
> return error;
>
> + /*
> + * I²C does not have built-in recovery, so retry on failure. This
> ensures,
> + * that the device probe will not fail for temporary issues on the bus.
> + * This is not needed for the sysfs calls (userspace will receive the
> error
> + * code and can start another query) and cannot be done for touch events
> + * (but that only means loosing one or two touch events anyways).
> + */
> + for (retry = 0; retry < 3; ++retry) {
> + error = exc3000_get_model(data);
> + if (!error)
> + break;
> + dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
> + retry + 1, error);
> + }
> +
> + if (error)
> + return error;
> +
> + dev_dbg(&client->dev, "TS Model: %s", data->model);
> +
> return 0;
> }
>
>
