From: "Murphy, Dan" <dmurphy@xxxxxx>
> Hemanth
> I have a few comments on this patch.
>
> +static ssize_t cma3000_store_attr_mdfftmr(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct cma3000_accl_data *data = platform_get_drvdata(pdev);
> + unsigned long val;
> + int error;
> +
> + error = strict_strtoul(buf, 0, &val);
> + if (error)
> + return error;
> +
> + mutex_lock(&data->mutex);
> + data->pdata.mdfftmr = val;
> +
> + disable_irq(data->client->irq);
> You should use disable_irq_nosync here. This may not work properly on SMP.
Can u explain why disable_irq will not work on SMP.
>
>> + if (val == CMARANGE_2G) {
>> + ctrl |= CMA3000_RANGE2G;
>> + data->pdata.g_range = CMARANGE_2G;
>> + } else if (val == CMARANGE_8G) {
>> + ctrl |= CMA3000_RANGE8G;
>> + data->pdata.g_range = CMARANGE_8G;
>
> Why are you modifying the platform data? Why not just keep it in a global or a glocal structure and modify it that way?
If you look carefully, the variable data is indeed a local structure.
>> + } else {
>> + error = -EINVAL;
>> + goto err_op_failed;
>> + }
>> +
>> + g_range = data->pdata.g_range;
>> + fuzz_x = data->pdata.fuzz_x;
>> + fuzz_y = data->pdata.fuzz_y;
>> + fuzz_z = data->pdata.fuzz_z;
> Why are you storing these locally and then using them once can't we eliminate these completely and just pass the platform data values into the set
> params?
I belive this is already discussed and agreed upon in the previous thread of discussion.
Pl refer the same.
>> +
>> + disable_irq(data->client->irq);
> You should use disable_irq_nosync here. This may not work properly on SMP.
>
Same comment as above
>> + cma3000_set(data, CMA3000_CTRL, ctrl, "ctrl");
>> +
>> + input_set_abs_params(data->input_dev, ABS_X, -g_range,
>> + g_range, fuzz_x, 0);
>> + input_set_abs_params(data->input_dev, ABS_Y, -g_range,
>> + g_range, fuzz_y, 0);
>> + input_set_abs_params(data->input_dev, ABS_Z, -g_range,
>> + g_range, fuzz_z, 0);
> Don't necessarily agree with modifying the parameters for the input device on the fly. Some implementations may be a read once on init and do not
> go back and check this.
Its the user space code that can modify the grange if required, so I suppose it will need to check
these values after modifying the range.
>
>
> + ret = request_threaded_irq(data->client->irq, NULL,
> + cma3000_thread_irq,
> + irqflags | IRQF_ONESHOT,
> + data->client->name, data);
>
> This is implemented wrong. You are doing a lot of processing in the IRQ context here. Especially calls out to a peripheral. The NULL should be
> your handler thread where you do all the device processing.
Are u sure u are referring to threaded irq, all the processing is being done in thread
context. Pl refer documentation for more details on threaded irqs.
>
> Also this implementation only suggests that the HW has the IRQ connected what about devices that the IRQ line was not connected?
>
This is currently not implemented, since I am not aware of any boards with this configuration. A polling method could be added
in future if the need arises.
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