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References: <20220703170039.2058202-1-LinoSanfilippo@gmx.de> <20220703170039.2058202-2-LinoSanfilippo@gmx.de>
In-Reply-To: <20220703170039.2058202-2-LinoSanfilippo@gmx.de>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Sun, 3 Jul 2022 20:27:39 +0200
Message-ID: <CAHp75VcU-gLQBvuesoYp-G91SjzeYB7PNCN17PGL7u139VZY2g@mail.gmail.com>
Subject: Re: [PATCH v2 1/9] serial: core: only get RS485 termination GPIO if supported
To:     Lino Sanfilippo <LinoSanfilippo@gmx.de>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Vladimir Zapolskiy <vz@mleia.com>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        devicetree <devicetree@vger.kernel.org>,
        "open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Lukas Wunner <lukas@wunner.de>, p.rosenberger@kunbus.com,
        Lino Sanfilippo <l.sanfilippo@kunbus.com>
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Precedence: bulk

On Sun, Jul 3, 2022 at 7:02 PM Lino Sanfilippo <LinoSanfilippo@gmx.de> wrote:
>
> From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
>
> In uart_get_rs485_mode() only try to get a termination GPIO if RS485 bus
> termination is supported by the driver. This prevents from allocating
> and holding a GPIO descriptor for the drivers lifetimg that will never be

lifetiming

> used.

...

>         port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
>                                                         GPIOD_OUT_LOW);
> +
> +       if (port->rs485_term_gpio &&

This check is incorrect. Either you need to move that after error
checking (that's what I personally prefer), or use !IS_ERR_OR_NULL().

> +           !(port->rs485_supported->flags & SER_RS485_TERMINATE_BUS)) {
> +               dev_warn(port->dev,
> +                       "%s (%d): RS485 termination gpio not supported by driver\n",
> +                       port->name, port->line);
> +               devm_gpiod_put(dev, port->rs485_term_gpio);
> +               port->rs485_term_gpio = NULL;
> +       }
> +
>         if (IS_ERR(port->rs485_term_gpio)) {
>                 ret = PTR_ERR(port->rs485_term_gpio);
>                 port->rs485_term_gpio = NULL;


-- 
With Best Regards,
Andy Shevchenko