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    SubjectRe: [PATCHv2 4/5] Input: EXC3000: Add support to query model and fw_version
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    Hi Sebastian,

    On 19/5/20 20:24, 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.reichel@collabora.com>
    > ---
    > drivers/input/touchscreen/exc3000.c | 138 +++++++++++++++++++++++++++-
    > 1 file changed, 137 insertions(+), 1 deletion(-)
    >
    > diff --git a/drivers/input/touchscreen/exc3000.c b/drivers/input/touchscreen/exc3000.c
    > index 9622cba514b3..1ae758bbf627 100644
    > --- a/drivers/input/touchscreen/exc3000.c
    > +++ b/drivers/input/touchscreen/exc3000.c
    > @@ -24,6 +24,9 @@
    > #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
    >
    > @@ -64,6 +67,11 @@ 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,
    > @@ -149,6 +157,28 @@ 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;
    > @@ -157,6 +187,12 @@ 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 */
    > @@ -184,11 +220,94 @@ static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
    > return IRQ_HANDLED;
    > }
    >
    > +static int 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);
    > +

    You should probably document the new sysfs entries, although are self-explanatory.

    > +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)
    > @@ -202,15 +321,19 @@ 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);
    > @@ -233,6 +356,19 @@ static int exc3000_probe(struct i2c_client *client)
    > if (error)
    > return error;
    >
    > + for (retry = 0; retry < 3; ++retry) {

    Just curious, is it known to fail and need retries?

    > + 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;
    > }
    >
    >

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