[PATCHv1,2/2] Input: EXC3000: Add support to query model and fw_version
diff mbox series

Message ID 20191107181010.17211-2-sebastian.reichel@collabora.com
State New
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Series
  • [PATCHv1,1/2] Input: EXC3000: add EXC80Hxx support
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Commit Message

Sebastian Reichel Nov. 7, 2019, 6:10 p.m. UTC
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.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/input/touchscreen/exc3000.c | 136 ++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)

Comments

Dmitry Torokhov Nov. 13, 2019, 12:23 a.m. UTC | #1
Hi Sebastian,

On Thu, Nov 07, 2019 at 07:10:10PM +0100, 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.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
>  drivers/input/touchscreen/exc3000.c | 136 ++++++++++++++++++++++++++++
>  1 file changed, 136 insertions(+)
> 
> diff --git a/drivers/input/touchscreen/exc3000.c b/drivers/input/touchscreen/exc3000.c
> index 7d695022082c..4c9f132629b9 100644
> --- a/drivers/input/touchscreen/exc3000.c
> +++ b/drivers/input/touchscreen/exc3000.c
> @@ -41,6 +41,11 @@ struct exc3000_data {
>  	struct touchscreen_properties prop;
>  	struct timer_list timer;
>  	u8 buf[2 * EXC3000_LEN_FRAME];
> +	char model[11];
> +	char fw_version[6];
> +	struct completion wait_event;
> +	struct mutex query_lock;
> +	int query_result;
>  };
>  
>  static void exc3000_report_slots(struct input_dev *input,
> @@ -121,6 +126,35 @@ static int exc3000_read_data(struct i2c_client *client,
>  	return 0;
>  }
>  
> +static void exc3000_query_interrupt(struct exc3000_data *data)
> +{
> +	u8 *buf = data->buf;
> +	int err;
> +
> +	data->query_result = 0;
> +
> +	err = i2c_master_recv(data->client, buf, EXC3000_LEN_FRAME);
> +	if (err < 0) {
> +		data->query_result = err;
> +		goto out;
> +	}
> +
> +	if (buf[0] == 0x42 && buf[4] == 'E') {
> +		memcpy(data->model, buf+5, 10);
> +		data->model[10] = '\0';
> +		goto out;
> +	} else if (buf[0] == 0x42 && buf[4] == 'D') {
> +		memcpy(data->fw_version, buf+5, 5);
> +		data->fw_version[5] = '\0';
> +		goto out;
> +	}
> +
> +	data->query_result = -EPROTO;
> +
> +out:
> +	complete(&data->wait_event);
> +}
> +
>  static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
>  {
>  	struct exc3000_data *data = dev_id;
> @@ -129,6 +163,11 @@ static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
>  	int slots, total_slots;
>  	int error;
>  
> +	if (mutex_is_locked(&data->query_lock)) {
> +		exc3000_query_interrupt(data);
> +		goto out;
> +	}
> +
>  	error = exc3000_read_data(data->client, buf, &total_slots);
>  	if (error) {
>  		/* Schedule a timer to release "stuck" contacts */
> @@ -156,12 +195,92 @@ static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +static int exc3000_get_fw_version(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(fw_version, S_IRUGO, exc3000_get_fw_version, NULL);
> +
> +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 exc3000_get_model_sysfs(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct exc3000_data *data = dev_get_drvdata(dev);
> +	int err = exc3000_get_model(data);

Do we really need to re-fetch model (and firmware ID) on each access?
Can we query it as probe time and cache? This I think would simplify the
driver, as you probably would not need to hook it into the ISR. Can you
just post a read/write transaction to fetch it without waiting for
interrupt? Or, if single transaction does not work and you need to wait
for certain time for response - just add msleep() and maybe mark driver
for async probe...

Thanks.
Martin Fuzzey Nov. 20, 2019, 11:47 a.m. UTC | #2
Hi Dmitry,

On 13/11/2019 01:23, Dmitry Torokhov wrote:
> Do we really need to re-fetch model (and firmware ID) on each access?
> Can we query it as probe time and cache? This I think would simplify the
> driver, as you probably would not need to hook it into the ISR. Can you
> just post a read/write transaction to fetch it without waiting for
> interrupt? Or, if single transaction does not work and you need to wait
> for certain time for response - just add msleep() and maybe mark driver
> for async probe...


Having the sysfs access actually read the data from the device can be 
useful to check that the I2C link is still working (in a test scenario).


The documentation does say that one should wait for an interrupt after 
issuing the commands.

The msleep() could work but the value would have to be empirical and 
could be fragile.

Furthermore what happens if a touch event occurs just after sending the 
query request?

Having the interrupt handler be the single read() point and dispatching 
solves that problem, even if it does complicate the driver to some extent.


One further thing is that there are other commands that may be added in 
the future that cannot be cached (commands to do tests or fimware 
updates for example).


Regards,


Martin
Martin Fuzzey Nov. 22, 2019, 5:43 p.m. UTC | #3
Hi Sebastian,

On 07/11/2019 19:10, 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.
>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
>   drivers/input/touchscreen/exc3000.c | 136 ++++++++++++++++++++++++++++
>   1 file changed, 136 insertions(+)
>
> diff --git a/drivers/input/touchscreen/exc3000.c b/drivers/input/touchscreen/exc3000.c
> index 7d695022082c..4c9f132629b9 100644
> --- a/drivers/input/touchscreen/exc3000.c
> +++ b/drivers/input/touchscreen/exc3000.c
> @@ -41,6 +41,11 @@ struct exc3000_data {
>   	struct touchscreen_properties prop;
>   	struct timer_list timer;
>   	u8 buf[2 * EXC3000_LEN_FRAME];
> +	char model[11];
> +	char fw_version[6];

These buffers are too small.

I know those are the values shown in the EETI "I2C Programming Guide" 
but, on my exc80H32 I have 16 bytes for the model and 14 for the fw_version.

It may even be possible to have larger, depends on the firmware / config 
blob that has been loaded.

The guide seems to be mostly an example. As nothing else is sent in the 
reply message, worst case the full frame would be filled.


>   
> +static void exc3000_query_interrupt(struct exc3000_data *data)
> +{
> +	u8 *buf = data->buf;
> +	int err;
> +
> +	data->query_result = 0;
> +
> +	err = i2c_master_recv(data->client, buf, EXC3000_LEN_FRAME);
> +	if (err < 0) {
> +		data->query_result = err;
> +		goto out;
> +	}
> +
> +	if (buf[0] == 0x42 && buf[4] == 'E') {
> +		memcpy(data->model, buf+5, 10);
> +		data->model[10] = '\0';

Maybe use sizeof() to avoid the hard coded 10?

> +		goto out;
> +	} else if (buf[0] == 0x42 && buf[4] == 'D') {
> +		memcpy(data->fw_version, buf+5, 5);
> +		data->fw_version[5] = '\0';
> +		goto out;
> +	}
> +


Ok so at least there won't be a buffer overflow but it will truncate.


> +static DEVICE_ATTR(fw_version, S_IRUGO, exc3000_get_fw_version, NULL);
> +


Maybe use DEVICE_ATTR_RO  to reduce the amount of boilerplate?


> +	input->dev.groups = exc3000_attribute_groups;


Hum, this adds the attributes to the input device (in /sys/class/input) 
but these attributes are really for the whole I2C device.

Wouldn't it be better to use devm_device_add_group() to add them to the 
I2C device?


> +	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);
> +	}
> +


Is there a particular reason why retries are needed?


Regards,


Martin

Patch
diff mbox series

diff --git a/drivers/input/touchscreen/exc3000.c b/drivers/input/touchscreen/exc3000.c
index 7d695022082c..4c9f132629b9 100644
--- a/drivers/input/touchscreen/exc3000.c
+++ b/drivers/input/touchscreen/exc3000.c
@@ -41,6 +41,11 @@  struct exc3000_data {
 	struct touchscreen_properties prop;
 	struct timer_list timer;
 	u8 buf[2 * EXC3000_LEN_FRAME];
+	char model[11];
+	char fw_version[6];
+	struct completion wait_event;
+	struct mutex query_lock;
+	int query_result;
 };
 
 static void exc3000_report_slots(struct input_dev *input,
@@ -121,6 +126,35 @@  static int exc3000_read_data(struct i2c_client *client,
 	return 0;
 }
 
+static void exc3000_query_interrupt(struct exc3000_data *data)
+{
+	u8 *buf = data->buf;
+	int err;
+
+	data->query_result = 0;
+
+	err = i2c_master_recv(data->client, buf, EXC3000_LEN_FRAME);
+	if (err < 0) {
+		data->query_result = err;
+		goto out;
+	}
+
+	if (buf[0] == 0x42 && buf[4] == 'E') {
+		memcpy(data->model, buf+5, 10);
+		data->model[10] = '\0';
+		goto out;
+	} else if (buf[0] == 0x42 && buf[4] == 'D') {
+		memcpy(data->fw_version, buf+5, 5);
+		data->fw_version[5] = '\0';
+		goto out;
+	}
+
+	data->query_result = -EPROTO;
+
+out:
+	complete(&data->wait_event);
+}
+
 static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
 {
 	struct exc3000_data *data = dev_id;
@@ -129,6 +163,11 @@  static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
 	int slots, total_slots;
 	int error;
 
+	if (mutex_is_locked(&data->query_lock)) {
+		exc3000_query_interrupt(data);
+		goto out;
+	}
+
 	error = exc3000_read_data(data->client, buf, &total_slots);
 	if (error) {
 		/* Schedule a timer to release "stuck" contacts */
@@ -156,12 +195,92 @@  static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int exc3000_get_fw_version(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(fw_version, S_IRUGO, exc3000_get_fw_version, NULL);
+
+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 exc3000_get_model_sysfs(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(model, S_IRUGO, exc3000_get_model_sysfs, NULL);
+
+static struct attribute *sysfs_attrs[] = {
+	&dev_attr_model.attr,
+	&dev_attr_fw_version.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,
 			 const struct i2c_device_id *id)
 {
 	struct exc3000_data *data;
 	struct input_dev *input;
 	int error;
+	int retry;
 
 	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
@@ -170,15 +289,19 @@  static int exc3000_probe(struct i2c_client *client,
 	data->client = client;
 	data->type = id->driver_data;
 	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 = "EETI EXC3000 Touch Screen";
 	input->id.bustype = BUS_I2C;
+	input->dev.groups = exc3000_attribute_groups;
 
 	if (data->type == EETI_EXC80Hxx) {
 		input_set_abs_params(input, ABS_MT_POSITION_X, 0, 16383, 0, 0);
@@ -204,6 +327,19 @@  static int exc3000_probe(struct i2c_client *client,
 	if (error)
 		return error;
 
+	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;
 }