From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932384AbdA3PdN (ORCPT ); Mon, 30 Jan 2017 10:33:13 -0500 Received: from mail-wm0-f45.google.com ([74.125.82.45]:38449 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932365AbdA3PdF (ORCPT ); Mon, 30 Jan 2017 10:33:05 -0500 Date: Mon, 30 Jan 2017 15:32:11 +0000 From: Lee Jones To: Peter Griffin Cc: gregkh@linuxfoundation.org, jslaby@suse.com, linux-serial@vger.kernel.org, robh+dt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel@stlinux.com Subject: Re: [STLinux Kernel] [PATCH 3/8] serial: st-asc: Read in all Pinctrl states Message-ID: <20170130153211.j75qemvwsq3cwqve@dell> References: <20170124134310.27512-1-lee.jones@linaro.org> <20170124134310.27512-4-lee.jones@linaro.org> <20170125112142.GE5680@griffinp-ThinkPad-X1-Carbon-2nd> <20170127115458.k4edg42nnna3bv4v@dell> <20170130142356.GA18710@griffinp-ThinkPad-X1-Carbon-2nd> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170130142356.GA18710@griffinp-ThinkPad-X1-Carbon-2nd> User-Agent: Mutt/1.6.2-neo (2016-08-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 30 Jan 2017, Peter Griffin wrote: > Hi Lee, > > On Fri, 27 Jan 2017, Lee Jones wrote: > > > On Wed, 25 Jan 2017, Peter Griffin wrote: > > > > > Hi Lee, > > > > > > On Tue, 24 Jan 2017, Lee Jones wrote: > > > > > > > There are now 2 possible separate/different Pinctrl states which can > > > > be provided from platform data. One which encompasses the lines > > > > required for HW flow-control (CTS/RTS) and another which does not > > > > specify these lines, such that they can be used via GPIO mechanisms > > > > for manually toggling (i.e. from a request by `stty`). > > > > > > > > Signed-off-by: Lee Jones > > > > --- > > > > drivers/tty/serial/st-asc.c | 28 ++++++++++++++++++++++++++++ > > > > 1 file changed, 28 insertions(+) > > > > > > > > diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c > > > > index 397df50..03801ed 100644 > > > > --- a/drivers/tty/serial/st-asc.c > > > > +++ b/drivers/tty/serial/st-asc.c > > > > @@ -37,10 +37,16 @@ > > > > #define ASC_FIFO_SIZE 16 > > > > #define ASC_MAX_PORTS 8 > > > > > > > > +/* Pinctrl states */ > > > > +#define DEFAULT 0 > > > > +#define MANUAL_RTS 1 > > > > > > Nit: Would be better to have them aligned. > > > > These are aligned in code. The patch format throws things out. > > > > Look, same lines with the "> > +" removed: > > Ah OK. > > > > > /* Pinctrl states */ > > #define DEFAULT 0 > > #define MANUAL_RTS 1 > > > > Try it. > > > > > > + > > > > struct asc_port { > > > > struct uart_port port; > > > > struct gpio_desc *rts; > > > > struct clk *clk; > > > > + struct pinctrl *pinctrl; > > > > + struct pinctrl_state *states[2]; > > > > unsigned int hw_flow_control:1; > > > > unsigned int force_m1:1; > > > > }; > > > > @@ -694,6 +700,7 @@ static int asc_init_port(struct asc_port *ascport, > > > > { > > > > struct uart_port *port = &ascport->port; > > > > struct resource *res; > > > > + int ret; > > > > > > > > port->iotype = UPIO_MEM; > > > > port->flags = UPF_BOOT_AUTOCONF; > > > > @@ -720,6 +727,27 @@ static int asc_init_port(struct asc_port *ascport, > > > > WARN_ON(ascport->port.uartclk == 0); > > > > clk_disable_unprepare(ascport->clk); > > > > > > > > + ascport->pinctrl = devm_pinctrl_get(&pdev->dev); > > > > + if (IS_ERR(ascport->pinctrl)) { > > > > + ret = PTR_ERR(ascport->pinctrl); > > > > + dev_err(&pdev->dev, "Failed to get Pinctrl: %d\n", ret); > > > > + } > > > > + > > > > + ascport->states[DEFAULT] = > > > > + pinctrl_lookup_state(ascport->pinctrl, "default"); > > > > + if (IS_ERR(ascport->states[DEFAULT])) { > > > > + ret = PTR_ERR(ascport->states[DEFAULT]); > > > > + dev_err(&pdev->dev, > > > > + "Failed to look up Pinctrl state 'default': %d\n", ret); > > > > + return ret; > > > > + } > > > > + > > > > + /* "manual-rts" state is optional */ > > > > + ascport->states[MANUAL_RTS] = > > > > + pinctrl_lookup_state(ascport->pinctrl, "manual-rts"); > > > > + if (IS_ERR(ascport->states[MANUAL_RTS])) > > > > + ascport->states[MANUAL_RTS] = NULL; > > > > + > > > > > > The different pinctrl states looks like a neat solution to the problem. > > > > > > My only concern here is that 'default' state is implying a hw-flow-control > > > pinmux config, and manual-rts is implying what is the current upstream > > > 'default' pinmux config. > > > > > > Which maybe ok if you update all uarts, but currently only serial0 > > > is updated. So the other uarts current 'default' is actually the same as serial0 > > > 'manual-rts' grouping, which conceptually is odd. > > > > > > Would it not be better to make 'manual-rts' the default state? As that aligns > > > to what is currently already the default for the other UARTS? And then make > > > hw-flow-control the optional state for serial0? > > > > > > That also has the advantage that 'default' has the same meaning with older DT's. > > > > The reason it was done is this was because none of the other UARTs > > require 2 separate Pinctrl configurations, only this one. Moreover, > > if they support RTS/CTS then I believe that the lines should be > > defined in Pinctrl. > > Yes I agree with that. > > > Thus, it was my plan to update all UART's default > > Pinctrl configs to include the RTS/CTS lines. > > > > I still don't see the point in changing the meaning of 'default' group and breaking > ABI if you don't need to? > > As far as I can tell if you swap the meaning of 'default' and 'maunal-rts' > groups you get all the benefits of this series whilst also maintaining backwards > compatbility with older DT's. What makes you think this will break ABI? -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog