From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?B?UGF3ZcWC?= Chmiel Subject: Re: [PATCH v2 1/2] Input: atmel_mxt_ts: Add support for optional regulators. Date: Wed, 18 Jul 2018 18:21:30 +0200 Message-ID: <2353752.vfvcsHJLR6@acerlaptop> References: <1531851386-17840-1-git-send-email-pawel.mikolaj.chmiel@gmail.com> <1531851386-17840-2-git-send-email-pawel.mikolaj.chmiel@gmail.com> <20180717210005.GA21416@hairyalien> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20180717210005.GA21416@hairyalien> Sender: linux-kernel-owner@vger.kernel.org To: Nick Dyer Cc: dmitry.torokhov@gmail.com, robh+dt@kernel.org, mark.rutland@arm.com, nicolas.ferre@microchip.com, alexandre.belloni@bootlin.com, linux-input@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: linux-input@vger.kernel.org On Tuesday, July 17, 2018 10:00:05 PM CEST Nick Dyer wrote: > On Tue, Jul 17, 2018 at 08:16:25PM +0200, Pawe=C5=82 Chmiel wrote: > > This patch adds optional regulators, which can be used to power > > up touchscreen. After enabling regulators, we need to wait 150msec. > > This value is taken from official driver. > >=20 > > It was tested on Samsung Galaxy i9000 (based on Samsung S5PV210 SOC). > >=20 > > Signed-off-by: Pawe=C5=82 Chmiel > > --- > > Changes from v1: > > - Enable regulators only if reset_gpio is present. > > - Switch from devm_regulator_get_optional to devm_regulator_get > > --- > > drivers/input/touchscreen/atmel_mxt_ts.c | 46 ++++++++++++++++++++++++= ++++++-- > > 1 file changed, 44 insertions(+), 2 deletions(-) > >=20 > > diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/t= ouchscreen/atmel_mxt_ts.c > > index 54fe190fd4bc..005f0fee9fc8 100644 > > --- a/drivers/input/touchscreen/atmel_mxt_ts.c > > +++ b/drivers/input/touchscreen/atmel_mxt_ts.c > > @@ -27,6 +27,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -194,10 +195,10 @@ enum t100_type { > > =20 > > /* Delay times */ > > #define MXT_BACKUP_TIME 50 /* msec */ > > -#define MXT_RESET_GPIO_TIME 20 /* msec */ > > #define MXT_RESET_INVALID_CHG 100 /* msec */ > > #define MXT_RESET_TIME 200 /* msec */ > > #define MXT_RESET_TIMEOUT 3000 /* msec */ > > +#define MXT_REGULATOR_DELAY 150 /* msec */ > > #define MXT_CRC_TIMEOUT 1000 /* msec */ > > #define MXT_FW_RESET_TIME 3000 /* msec */ > > #define MXT_FW_CHG_TIMEOUT 300 /* msec */ > > @@ -310,6 +311,8 @@ struct mxt_data { > > struct t7_config t7_cfg; > > struct mxt_dbg dbg; > > struct gpio_desc *reset_gpio; > > + struct regulator *vdd_reg; > > + struct regulator *avdd_reg; > > =20 > > /* Cached parameters from object table */ > > u16 T5_address; > > @@ -3076,6 +3079,22 @@ static int mxt_probe(struct i2c_client *client, = const struct i2c_device_id *id) > > return error; > > } > > =20 > > + data->vdd_reg =3D devm_regulator_get(&client->dev, "vdd"); > > + if (IS_ERR(data->vdd_reg)) { > > + error =3D PTR_ERR(data->vdd_reg); > > + dev_err(&client->dev, "Failed to get vdd regulator: %d\n", > > + error); > > + return error; > > + } > > + > > + data->avdd_reg =3D devm_regulator_get(&client->dev, "avdd"); > > + if (IS_ERR(data->avdd_reg)) { > > + error =3D PTR_ERR(data->avdd_reg); > > + dev_err(&client->dev, "Failed to get avdd regulator: %d\n", > > + error); > > + return error; > > + } > > + > > error =3D devm_request_threaded_irq(&client->dev, client->irq, > > NULL, mxt_interrupt, IRQF_ONESHOT, > > client->name, data); > > @@ -3087,7 +3106,26 @@ static int mxt_probe(struct i2c_client *client, = const struct i2c_device_id *id) > > disable_irq(client->irq); > > =20 > > if (data->reset_gpio) { > > - msleep(MXT_RESET_GPIO_TIME); > > + error =3D regulator_enable(data->vdd_reg); > > + if (error) { > > + dev_err(&client->dev, "Failed to enable vdd regulator: %d\n", > > + error); > > + return error; > > + } > > + > > + error =3D regulator_enable(data->avdd_reg); > > + if (error) { > > + dev_err(&client->dev, "Failed to enable avdd regulator: %d\n", > > + error); > > + return error; > > + } > > + > > + /* > > + * According to maXTouch power sequencing specification, RESET line > > + * must be kept low until some time after regulators come up to > > + * voltage > > + */ > > + msleep(MXT_REGULATOR_DELAY); > > gpiod_set_value(data->reset_gpio, 1); > > msleep(MXT_RESET_INVALID_CHG); >=20 > Hi Pawel- >=20 > I see you've borrowed some of the logic from the patch I wrote a while > back (see https://github.com/ndyer/linux/commit/8e9687e41ed062 ) Actually, i was looking at https://github.com/atmel-maxtouch/linux/blob/max= touch-v3.14/drivers/input/touchscreen/atmel_mxt_ts.c (and didn't saw Your p= atch till now). Are You going to submit it? (it has more functionalities - for example susp= end mode read from device tree). >=20 > The correct behaviour according to Atmel should be: >=20 > * Make RESET zero > * Bring up regulators > * Wait for a period to settle (150 msec) > * Release RESET > * Wait for 100 msec whilst device gets through bootloader > * Wait for CHG line assert before reading info block >=20 > I can't see the first and last steps in your patch at present. About first step - reset_gpio is readed by using devm_gpiod_get_optional wi= th GPIOD_OUT_LOW flag, so i think (but might be wrong) that we don't need = to set this gpio value again to 0 before enabling regulators, since currently only place where reset_gpio is used is in driver probe (in = Your patch it is used in other cases/places - for example in mxt_start/stop= , when we enable regulators). About missing wait after releasing reset, shouldn't this be separate patch = (since currently driver is not doing it)? I can prepare it and send with ot= her in next version. Thanks for feedback >=20 > The only downside with this approach is that there are a lot of > delays during driver probe, but I believe the asynchronous probe stuff > that's landed since I wrote the original patch should address that. >=20 > cheers >=20 > Nick >=20 > > } > > @@ -3116,6 +3154,10 @@ static int mxt_remove(struct i2c_client *client) > > struct mxt_data *data =3D i2c_get_clientdata(client); > > =20 > > disable_irq(data->irq); > > + if (data->reset_gpio) { > > + regulator_disable(data->avdd_reg); > > + regulator_disable(data->vdd_reg); > > + } > > sysfs_remove_group(&client->dev.kobj, &mxt_attr_group); > > mxt_free_input_device(data); > > mxt_free_object_table(data); >=20