Re: [PATCH] Input: edt-ft5x06 - Switch to newer gpio framework

Franklin S Cooper Jr.
2015-08-24T20:23:43Z

On 08/24/2015 03:16 PM, Franklin S Cooper Jr. wrote:
>
> On 08/24/2015 03:01 PM, Dmitry Torokhov wrote:
>> On Mon, Aug 24, 2015 at 02:48:36PM -0500, Franklin S Cooper Jr. wrote:
>>> On 08/24/2015 02:41 PM, Dmitry Torokhov wrote:
>>>> On Fri, Aug 21, 2015 at 02:08:32PM -0500, Franklin S Cooper Jr wrote:
>>>>> The current/old gpio framework used doesn't properly listen to
>>>>> ACTIVE_LOW and ACTIVE_HIGH flags. The newer gpio framework takes into
>>>>> account these flags when setting gpio values.
>>>>>
>>>>> Also use gpiod_set_value_cansleep since wake and reset pins can be
>>>>> provided by bus based io expanders.
>>>>>
>>>>> Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
>>>>> ---
>>>>> .../bindings/input/touchscreen/edt-ft5x06.txt | 4 +-
>>>>> drivers/input/touchscreen/edt-ft5x06.c | 115 +++++++--------------
>>>>> include/linux/input/edt-ft5x06.h | 4 +-
>>>>> 3 files changed, 43 insertions(+), 80 deletions(-)
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
>>>>> index 76db967..9330d4d 100644
>>>>> --- a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
>>>>> +++ b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
>>>>> @@ -50,6 +50,6 @@ Example:
>>>>> pinctrl-0 = <&edt_ft5x06_pins>;
>>>>> interrupt-parent = <&gpio2>;
>>>>> interrupts = <5 0>;
>>>>> - reset-gpios = <&gpio2 6 1>;
>>>>> - wake-gpios = <&gpio4 9 0>;
>>>>> + reset-gpios = <&gpio2 6 GPIO_ACTIVE_LOW>;
>>>>> + wake-gpios = <&gpio4 9 GPIO_ACTIVE_HIGH>;
>>>>> };
>>>>> diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
>>>>> index 394b1de..6b128b3 100644
>>>>> --- a/drivers/input/touchscreen/edt-ft5x06.c
>>>>> +++ b/drivers/input/touchscreen/edt-ft5x06.c
>>>>> @@ -91,9 +91,9 @@ struct edt_ft5x06_ts_data {
>>>>> u16 num_x;
>>>>> u16 num_y;
>>>>>
>>>>> - int reset_pin;
>>>>> - int irq_pin;
>>>>> - int wake_pin;
>>>>> + struct gpio_desc *reset_pin;
>>>>> + struct gpio_desc *wake_pin;
>>>>> + struct gpio_desc *irq_pin;
>>>>>
>>>>> #if defined(CONFIG_DEBUG_FS)
>>>>> struct dentry *debug_dir;
>>>>> @@ -755,36 +755,14 @@ edt_ft5x06_ts_teardown_debugfs(struct edt_ft5x06_ts_data *tsdata)
>>>>> static int edt_ft5x06_ts_reset(struct i2c_client *client,
>>>>> struct edt_ft5x06_ts_data *tsdata)
>>>>> {
>>>>> - int error;
>>>>> -
>>>>> - if (gpio_is_valid(tsdata->wake_pin)) {
>>>>> - error = devm_gpio_request_one(&client->dev,
>>>>> - tsdata->wake_pin, GPIOF_OUT_INIT_LOW,
>>>>> - "edt-ft5x06 wake");
>>>>> - if (error) {
>>>>> - dev_err(&client->dev,
>>>>> - "Failed to request GPIO %d as wake pin, error %d\n",
>>>>> - tsdata->wake_pin, error);
>>>>> - return error;
>>>>> - }
>>>>> -
>>>>> + if (tsdata->wake_pin) {
>>>>> msleep(5);
>>>>> - gpio_set_value(tsdata->wake_pin, 1);
>>>>> + gpiod_set_value_cansleep(tsdata->wake_pin, 1);
>>>>> }
>>>>> - if (gpio_is_valid(tsdata->reset_pin)) {
>>>>> - /* this pulls reset down, enabling the low active reset */
>>>>> - error = devm_gpio_request_one(&client->dev,
>>>>> - tsdata->reset_pin, GPIOF_OUT_INIT_LOW,
>>>>> - "edt-ft5x06 reset");
>>>>> - if (error) {
>>>>> - dev_err(&client->dev,
>>>>> - "Failed to request GPIO %d as reset pin, error %d\n",
>>>>> - tsdata->reset_pin, error);
>>>>> - return error;
>>>>> - }
>>>>>
>>>>> + if (tsdata->reset_pin) {
>>>>> msleep(5);
>>>>> - gpio_set_value(tsdata->reset_pin, 1);
>>>>> + gpiod_set_value_cansleep(tsdata->reset_pin, 1);
>>>> So this leaves the reset pin active. How exactly was this tested?
>>> Normally if the output gpio connected to the reset pin is ACTIVE_HIGH then this will take the tsc out of reset since
>>> the reset pin is active low. However, I have a board that has an inverter between the gpio and reset pin. So if I leave
>>> the gpio as ACTIVE_HIGH then the inverter would cause the reset pin to go low which will keep it in reset. So instead
>>> I set the gpio to ACTIVE_LOW which gives me the expected result.
>> I do not really care about particular board. Assuming that polarity of
>> the GPIO in DTS is specified correctly the effect of:
>>
>> gpiod_set_value_cansleep(tsdata->reset_pin, 1);
>>
>> is reset pin being _active_, i.e. the chip is staying in reset state.
> Setting the reset pin to 1/high will take the tsc out of reset. Setting the pin to 0/low will put the tsc into reset mode.
>> By the way, both reset and wake pins are active low according to the
>> data sheet I found.
> Your right. Reset and wake are both active low. However, that part of the code is trying to get the tsc out of reset which is
> why its setting the value to 1. Setting the pin to 1 was being done even before my patch.
>
> What has changed was removing the below line which puts the tsc in reset.
>
> error = devm_gpio_request_one(&client->dev, tsdata->reset_pin, GPIOF_OUT_INIT_LOW,"edt-ft5x06 reset");
>
> However, the above line isn't needed since when I request the gpio I already configured it as an output
> with a default value of 0.
>
Sorry accidentally hit reply in this thread instead of reply all. Adding back everyone removed from CC list.
>> Thanks.
>>