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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hxr9Z-0006SH-Gj; Wed, 14 Aug 2019 11:09:17 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hxr8Z-0006KE-Pr for linux-arm-kernel@lists.infradead.org; Wed, 14 Aug 2019 11:08:17 +0000 Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1hxr8R-0006S4-9I; Wed, 14 Aug 2019 13:08:07 +0200 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1hxr8O-0000eI-EU; Wed, 14 Aug 2019 13:08:04 +0200 Date: Wed, 14 Aug 2019 13:08:04 +0200 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Geert Uytterhoeven Subject: Re: [PATCH 1/3] serial: atmel: Don't check for mctrl_gpio_to_gpiod() returning error Message-ID: <20190814110804.2ceo2upc3su7muup@pengutronix.de> References: <20190814092757.13726-1-geert+renesas@glider.be> <20190814092924.13857-1-geert+renesas@glider.be> <20190814092924.13857-2-geert+renesas@glider.be> <20190814093558.xlx5ck54dw2dgb6k@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190814_040816_069804_7D199702 X-CRM114-Status: GOOD ( 22.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alexandre Belloni , Pengutronix Kernel Team , Geert Uytterhoeven , "open list:SERIAL DRIVERS" , Richard Genoud , Greg Kroah-Hartman , Sascha Hauer , Frieder Schrempf , Linux-Renesas , Ludovic Desroches , NXP Linux Team , Fabio Estevam , Jiri Slaby , Shawn Guo , Linux ARM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Aug 14, 2019 at 12:20:33PM +0200, Geert Uytterhoeven wrote: > Hi Uwe, > = > On Wed, Aug 14, 2019 at 11:36 AM Uwe Kleine-K=F6nig > wrote: > > On Wed, Aug 14, 2019 at 11:29:22AM +0200, Geert Uytterhoeven wrote: > > > Since commit 1d267ea6539f2663 ("serial: mctrl-gpio: simplify init > > > routine"), mctrl_gpio_init() returns failure if the assignment to any > > > member of the gpio array results in an error pointer. > > > Since commit c359522194593815 ("serial: mctrl_gpio: Avoid probe failu= res > > > in case of missing gpiolib"), mctrl_gpio_to_gpiod() returns NULL in t= he > > > !CONFIG_GPIOLIB case. > > > Hence there is no longer a need to check for mctrl_gpio_to_gpiod() > > > returning an error value. A simple NULL check is sufficient. > > > > > > This follows the spirit of commit 445df7ff3fd1a0a9 ("serial: mctrl-gp= io: > > > drop usages of IS_ERR_OR_NULL") in the mctrl-gpio core. > > > > > > Signed-off-by: Geert Uytterhoeven > > > --- > > > drivers/tty/serial/atmel_serial.c | 12 ++++-------- > > > 1 file changed, 4 insertions(+), 8 deletions(-) > > > > > > diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/a= tmel_serial.c > > > index 19a85d6fe3d20541..e9620a81166b7dc1 100644 > > > --- a/drivers/tty/serial/atmel_serial.c > > > +++ b/drivers/tty/serial/atmel_serial.c > > > @@ -303,32 +303,28 @@ static unsigned int atmel_get_lines_status(stru= ct uart_port *port) > > > > > > mctrl_gpio_get(atmel_port->gpios, &ret); > > > > > > - if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios, > > > - UART_GPIO_CTS))) { > > > + if (mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) { > > > if (ret & TIOCM_CTS) > > > status &=3D ~ATMEL_US_CTS; > > > else > > > status |=3D ATMEL_US_CTS; > > > } > > > > The change is fine, but it seems the atmel driver doesn't use mctrl_gpio > > as expected (at least as expected by me). IMHO driving the hardware > > function of the CTS pin shouldn't be conditional on the presence of a > > cts-gpio. Is there a reason not to just drop the if completely? > = > The above code returns the hardware status if CTS is not a GPIO, and > returns (overrides with) the GPIO status if CTS is a GPIO. > Isn't that correct, or am I missing something? I took a deeper look into this driver now. The task for atmel_get_lines_status() isn't to implement the get_mctrl() callback. Instead this is called in the irqhandler to set ATMEL_US_RI in a "pending" value that then later in atmel_handle_status() is translated to a "ring" event that is handled there. So the right cleanup would be to let atmel_get_lines_status() just be return atmel_uart_readl(port, ATMEL_US_CSR); . If something happend on the lines implemented as gpio the driver's irq function isn't called anyhow. Best regards Uwe -- = Pengutronix e.K. | Uwe Kleine-K=F6nig | Industrial Linux Solutions | http://www.pengutronix.de/ | _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel