On Tuesday 28 February 2017 07:46 AM, Kevin Hilman wrote:
> + Sekhar for the board-da850-evm questions.
>
> Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> writes:
>
>> Hi Dmitry,
>>
>> On Sat, Feb 25, 2017 at 8:08 PM, Dmitry Torokhov
>> <dmitry.torokhov@xxxxxxxxx> wrote:
>>> Hi Yegor,
>>>
>>> On Fri, Feb 24, 2017 at 04:42:25PM +0100, yegorslists@xxxxxxxxxxxxxx wrote:
>>>> From: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
>>>>
>>>> This patch adds support for DT to tps6507x-ts driver.
>>>>
>>>> Signed-off-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
>>>> ---
>>>> drivers/input/touchscreen/tps6507x-ts.c | 70 ++++++++++++++++++++-------------
>>>> 1 file changed, 42 insertions(+), 28 deletions(-)
>>>>
>>>> diff --git a/drivers/input/touchscreen/tps6507x-ts.c b/drivers/input/touchscreen/tps6507x-ts.c
>>>> index 5bf1ec6..2d61220 100644
>>>> --- a/drivers/input/touchscreen/tps6507x-ts.c
>>>> +++ b/drivers/input/touchscreen/tps6507x-ts.c
>>>> @@ -22,6 +22,8 @@
>>>> #include <linux/mfd/tps6507x.h>
>>>> #include <linux/input/tps6507x-ts.h>
>>>> #include <linux/delay.h>
>>>> +#include <linux/of.h>
>>>> +#include <linux/of_device.h>
>>>>
>>>> #define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
>>>> #define TPS_DEFAULT_MIN_PRESSURE 0x30
>>>> @@ -199,33 +201,52 @@ static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
>>>> tps6507x_adc_standby(tsc);
>>>> }
>>>>
>>>> +static void tsc_init_data(struct tps6507x_ts *tsc,
>>>> + struct input_dev *input_dev)
>>>> +{
>>>> + struct device_node *node = tsc->dev->of_node;
>>>> + const struct tps6507x_board *tps_board =
>>>> + dev_get_platdata(tsc->dev);
>>>> + const struct touchscreen_init_data *init_data = NULL;
>>>> +
>>>> + if (tps_board)
>>>> + /*
>>>> + * init_data points to array of touchscreen_init structure
>>>> + * coming from the board-evm file.
>>>> + */
>>>> + init_data = tps_board->tps6507x_ts_init_data;
>>>> +
>>>> + if (node == NULL && init_data == NULL) {
>>>> + tsc->poll_dev->poll_interval = TSC_DEFAULT_POLL_PERIOD;
>>>> + tsc->min_pressure = TPS_DEFAULT_MIN_PRESSURE;
>>>
>>> I think you want to always init with defaults, then override with
>>> property data.
>>
>> ACK
>>
>>>> + } else if (init_data) {
>>>> + tsc->poll_dev->poll_interval = init_data->poll_period;
>>>> + tsc->min_pressure = init_data->min_pressure;
>>>> + input_dev->id.vendor = init_data->vendor;
>>>> + input_dev->id.product = init_data->product;
>>>> + input_dev->id.version = init_data->version;
>>>> + } else if (node) {
>>>> + of_property_read_u32(node, "ti,poll-period",
>>>> + &tsc->poll_dev->poll_interval);
>>>> + of_property_read_u16(node, "ti,min-pressure",
>>>> + &tsc->min_pressure);
>>>
>>> Anything but u32 is better avoided in DT as it requires special
>>> annotation which is easily forgotten.
>>
>> Will convert to 32-bit values.
>>
>>> I also would prefer if we switched to generic device properties and
>>> retired the static init data.
>>
>> do you mean converting the driver to DT-only variant?
>>
>>>> + of_property_read_u16(node, "ti,vendor",
>>>> + &input_dev->id.vendor);
>>>> + of_property_read_u16(node, "ti,product",
>>>> + &input_dev->id.product);
>>>
>>> Would we not know vendor and product from the compatible string?
>>>
>>>> + of_property_read_u16(node, "ti,version",
>>>> + &input_dev->id.version);
>>>
>>> I wonder if anyone cares about this.
>>
>> I've looked at other touchscreen drivers and this structure seems to
>> be filled mostly for the RS232 connected drivers. So I'd suggest just
>> to leave vendor, product and version at 0 and not provide these values
>> via DT. At least tslib and hence Qt is working without these values
>> set.
>>
>> @Kevin: so far the only user of this touch driver is da850-evm board.
>> Can we drop the values for the id structure? Btw. what else is needed
It seems like it was mostly added so it can be read through sysfs. But
since it has been exposed to userspace, I am not sure if it can simply
be dropped. May be used hardcoded values for these in the driver based
on compatible string ?
>> to remove arch/arm/mach-davinci/board-da850-evm.c completely?
A lot of work has recently happened that should make this possible in
the near future. There are things like NOR flash, RMII ethernet, cpuidle
support etc which needs work. Ultimately we want a feature compatible
device-tree support to exist for at least one kernel version before the
board file is removed.
Thanks,
Sekhar
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