From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Heiny Subject: Re: [PATCH V2] input synaptics-rmi4: Bug fixes to ATTN GPIO handling. Date: Wed, 18 Dec 2013 17:23:33 -0800 Message-ID: <52B24A95.8070100@synaptics.com> References: <1387311361-29411-1-git-send-email-cheiny@synaptics.com> <20131218143944.GG28504@core.coreip.homeip.net> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from us-mx2.synaptics.com ([192.147.44.131]:6121 "EHLO us-mx2.synaptics.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751140Ab3LSBXh (ORCPT ); Wed, 18 Dec 2013 20:23:37 -0500 In-Reply-To: <20131218143944.GG28504@core.coreip.homeip.net> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: Linux Input , Andrew Duggan , Vincent Huang , Vivian Ly , Daniel Rosenberg , Jean Delvare , Joerie de Gram , Linus Walleij , Benjamin Tissoires On 12/18/2013 06:39 AM, Dmitry Torokhov wrote: > Hi Chris, > > On Tue, Dec 17, 2013 at 12:16:01PM -0800, Christopher Heiny wrote: >> This patch fixes two bugs in handling of the RMI4 attention line GPIO. >> >> 1) in enable_sensor(), make sure the attn_gpio is defined before attempting to >> get its value. >> >> 2) in rmi_driver_probe(), declare the name of the attn_gpio, then >> request the attn_gpio before attempting to export it. >> >> Also introduces a GPIO_LABEL constant for identifying the attention GPIO. >> > > I was looking at the patch some more and I have some concerns with it. > >> Signed-off-by: Christopher Heiny >> Cc: Dmitry Torokhov >> Cc: Benjamin Tissoires >> >> --- >> >> drivers/input/rmi4/rmi_driver.c | 28 +++++++++++++++++----------- >> 1 file changed, 17 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c >> index a30c7d3..33fb8f8 100644 >> --- a/drivers/input/rmi4/rmi_driver.c >> +++ b/drivers/input/rmi4/rmi_driver.c >> @@ -169,7 +169,7 @@ static int enable_sensor(struct rmi_device *rmi_dev) >> >> data->enabled = true; >> >> - if (!pdata->level_triggered && >> + if (pdata->attn_gpio && !pdata->level_triggered && > > O is perfectly fine GPIO number, you want to use gpio_is_valid() hete. I > also wonder why do you need such elaborate check. Can we simply "flush" > device before enabling interrupts? Hmmm. gpio_is_valid() is a good suggestion. However, I think we can do away with the whole check on the ATTN gpio, and just call process_interrupt_requests(). That will both flush the state and handle any important pending events. In the typical use case for enable_sensor(), the RMI4 device will either be just coming up or else coming out of a diagnostic mode, and there will at least be a status event to handle. In the off-case where there is nothing pending (that is, ATTN not asserted), the overhead is pretty low - just a quick read of the interrupt status register. > >> gpio_get_value(pdata->attn_gpio) == pdata->attn_polarity) >> retval = process_interrupt_requests(rmi_dev); >> >> @@ -807,6 +807,8 @@ static int rmi_driver_remove(struct device *dev) >> return 0; >> } >> >> +static const char GPIO_LABEL[] = "attn"; >> + >> static int rmi_driver_probe(struct device *dev) >> { >> struct rmi_driver *rmi_driver; >> @@ -959,20 +961,24 @@ static int rmi_driver_probe(struct device *dev) >> } >> >> if (IS_ENABLED(CONFIG_RMI4_DEV) && pdata->attn_gpio) { >> - retval = gpio_export(pdata->attn_gpio, false); >> + retval = gpio_request(pdata->attn_gpio, GPIO_LABEL); > > Here it is too late to request GPIO. You have been converting it to IRQ, > enabling that IRQ and calling gpio_get_value() so GPIO should have > already been requested by now. > > So you need to move this code up. I'll give that a try. > You may also consider using > gpio_request_one() and use GPIOF_EXPORT flag if you want to export it. > It would also be nice to set the direction (GPIOF_DIR_IN). Both of these are good ideas. > I also do not see matching call to gpio_free() in remove(). Neither do I :-(. We'll update. > >> if (retval) { >> - dev_warn(dev, "WARNING: Failed to export ATTN gpio!\n"); >> - retval = 0; >> + dev_warn(dev, "WARNING: Failed to request ATTN gpio %d, code: %d.\n", >> + pdata->attn_gpio, retval); >> } else { >> - retval = gpio_export_link(dev, >> - "attn", pdata->attn_gpio); >> + retval = gpio_export(pdata->attn_gpio, false); >> if (retval) { >> - dev_warn(dev, >> - "WARNING: Failed to symlink ATTN gpio!\n"); >> - retval = 0; >> + dev_warn(dev, "WARNING: Failed to export ATTN gpio %d, code: %d.\n", >> + pdata->attn_gpio, retval); >> } else { >> - dev_info(dev, "Exported ATTN GPIO %d.", >> - pdata->attn_gpio); >> + retval = gpio_export_link(dev, GPIO_LABEL, >> + pdata->attn_gpio); >> + if (retval) >> + dev_warn(dev, >> + "WARNING: Failed to symlink ATTN gpio!\n"); >> + else >> + dev_info(dev, "Exported ATTN GPIO %d.", >> + pdata->attn_gpio); >> } >> } >> } > > Thanks. >