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[109.252.170.211]) by smtp.googlemail.com with ESMTPSA id u2sm614441ljo.48.2020.09.18.06.32.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Sep 2020 06:32:51 -0700 (PDT) Subject: Re: [PATCH v2 2/2] Input: atmel_mxt_ts - wake mXT1386 from deep-sleep mode To: Jiada Wang , nick@shmanahar.org, dmitry.torokhov@gmail.com, robh+dt@kernel.org Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, andy.shevchenko@gmail.com, erosca@de.adit-jv.com, Andrew_Gabbasov@mentor.com References: <20200918125601.8210-1-jiada_wang@mentor.com> <20200918125601.8210-2-jiada_wang@mentor.com> From: Dmitry Osipenko Message-ID: <2c3e093a-dc75-d315-519d-9b8fbab9b41b@gmail.com> Date: Fri, 18 Sep 2020 16:32:50 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200918125601.8210-2-jiada_wang@mentor.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org 18.09.2020 15:56, Jiada Wang пишет: > According to datasheet, mXT1386 chip has a WAKE line, it is used > to wake the chip up from deep sleep mode before communicating with > it via the I2C-compatible interface. > > if the WAKE line is connected to a GPIO line, the line must be > asserted 25 ms before the host attempts to communicate with the mXT1386. > If the WAKE line is connected to the SCL pin, the mXT1386 will send a > NACK on the first attempt to address it, the host must then retry 25 ms > later. > > This patch introduces mxt_wake() which does a dummy i2c read, follows > with a 25 ms sleep for mXT1386 chip. mxt_wake() is added to > mxt_initialize(), mxt_load_fw() and mxt_start() to ensure before any > actual i2c transfer, mxt_wake() can be executed. > > Added new compatible string "atmel,mXT1386". > > Signed-off-by: Jiada Wang Hello, Jiada! This not critical, but yours suggested-by tag always should be the last line of the commit message. It's like you're signing all the words that were written by you. > Suggested-by: Dmitry Osipenko > --- > drivers/input/touchscreen/atmel_mxt_ts.c | 27 ++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c > index a2189739e30f..d580050a237f 100644 > --- a/drivers/input/touchscreen/atmel_mxt_ts.c > +++ b/drivers/input/touchscreen/atmel_mxt_ts.c > @@ -196,6 +196,7 @@ enum t100_type { > #define MXT_CRC_TIMEOUT 1000 /* msec */ > #define MXT_FW_RESET_TIME 3000 /* msec */ > #define MXT_FW_CHG_TIMEOUT 300 /* msec */ > +#define MXT_WAKEUP_TIME 25 /* msec */ > > /* Command to unlock bootloader */ > #define MXT_UNLOCK_CMD_MSB 0xaa > @@ -2099,12 +2100,33 @@ static void mxt_config_cb(const struct firmware *cfg, void *ctx) > release_firmware(cfg); > } > > +static void mxt_wake(struct mxt_data *data) > +{ > + struct i2c_client *client = data->client; > + struct device *dev = &data->client->dev; > + struct device_node *np = dev->of_node; > + union i2c_smbus_data dummy; > + > + if (!of_device_is_compatible(np, "atmel,mXT1386")) > + return; I'm not sure whether you misses the previous answers from Dmitry Torokhov and Rob Herring, but they suggested to add a new device-tree property which should specify the atmel,wakeup-method. There are 3 possible variants: - NONE - GPIO - I2C-SCL Hence we should bail out from mxt_wake() if method is set to NONE or GPIO. Perhaps we could even skip the GPIO method entirely by not mentioning it anywhere, since this method isn't needed for now. Nevertheless, I think it will be good to add DT compatible for the "atmel,mXT1386", hence this part is good to me. > + /* TODO: add WAKE-GPIO support */ > + > + i2c_smbus_xfer(client->adapter, client->addr, > + 0, I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, > + &dummy); > + There is no need to sleep if there was no I2C error, meaning that device wasn't in a deep-sleep mode. Please add a check for the value returned by i2c_smbus_xfer() and invoke the msleep() only in a case of the I2C error condition. > + msleep(MXT_WAKEUP_TIME); > +} > + > static int mxt_initialize(struct mxt_data *data) > { > struct i2c_client *client = data->client; > int recovery_attempts = 0; > int error; > > + mxt_wake(data); > + > while (1) { I assume the mxt_wake() should be placed here, since there is a 3 seconds timeout in the end of the while-loop, meaning that device may get back into deep-sleep on a retry. > error = mxt_read_info_block(data); > if (!error) > @@ -2787,6 +2809,8 @@ static int mxt_load_fw(struct device *dev, const char *fn) > if (ret) > goto release_firmware; > > + mxt_wake(data); > + > if (!data->in_bootloader) { > /* Change to the bootloader mode */ > data->in_bootloader = true; > @@ -2928,6 +2952,7 @@ static const struct attribute_group mxt_attr_group = { > > static void mxt_start(struct mxt_data *data) > { > + mxt_wake(data); Shouldn't the mxt_wake() be under the MXT_SUSPEND_DEEP_SLEEP switch? The wake-up should be needed only for waking from deep-sleep mode. > switch (data->suspend_mode) { > case MXT_SUSPEND_T9_CTRL: > mxt_soft_reset(data); > @@ -3185,6 +3210,7 @@ static SIMPLE_DEV_PM_OPS(mxt_pm_ops, mxt_suspend, mxt_resume); > > static const struct of_device_id mxt_of_match[] = { > { .compatible = "atmel,maxtouch", }, > + { .compatible = "atmel,mXT1386", }, > /* Compatibles listed below are deprecated */ > { .compatible = "atmel,qt602240_ts", }, > { .compatible = "atmel,atmel_mxt_ts", }, > @@ -3209,6 +3235,7 @@ static const struct i2c_device_id mxt_id[] = { > { "atmel_mxt_tp", 0 }, > { "maxtouch", 0 }, > { "mXT224", 0 }, > + { "mXT1386", 0 }, > { } > }; > MODULE_DEVICE_TABLE(i2c, mxt_id); >