From: Peter Griffin <peter.griffin@linaro.org>
To: Lee Jones <lee.jones@linaro.org>
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
Date: Mon, 30 Jan 2017 14:23:56 +0000 [thread overview]
Message-ID: <20170130142356.GA18710@griffinp-ThinkPad-X1-Carbon-2nd> (raw)
In-Reply-To: <20170127115458.k4edg42nnna3bv4v@dell>
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 <lee.jones@linaro.org>
> > > ---
> > > 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.
regards,
Peter.
next prev parent reply other threads:[~2017-01-30 14:32 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-24 13:43 [PATCH 0/8] serial: st-asc: Allow handling of RTS line Lee Jones
2017-01-24 13:43 ` [PATCH 1/8] serial: st-asc: Ignore the parity error bit if 8-bit mode is enabled Lee Jones
2017-01-25 11:02 ` [STLinux Kernel] " Peter Griffin
2017-01-24 13:43 ` [PATCH 2/8] serial: st-asc: Provide RTS functionality Lee Jones
2017-01-25 11:03 ` [STLinux Kernel] " Peter Griffin
2017-01-24 13:43 ` [PATCH 3/8] serial: st-asc: Read in all Pinctrl states Lee Jones
2017-01-24 21:28 ` kbuild test robot
2017-01-25 11:21 ` [STLinux Kernel] " Peter Griffin
2017-01-27 11:54 ` Lee Jones
2017-01-30 14:23 ` Peter Griffin [this message]
2017-01-30 15:32 ` Lee Jones
2017-01-30 16:10 ` Peter Griffin
2017-01-30 19:11 ` Lee Jones
2017-01-30 22:35 ` Peter Griffin
2017-01-31 10:13 ` Lee Jones
2017-01-31 11:31 ` Peter Griffin
2017-01-31 12:27 ` Lee Jones
2017-02-01 11:50 ` Peter Griffin
2017-02-01 12:47 ` Lee Jones
2017-01-24 13:43 ` [PATCH 4/8] serial: st-asc: (De)Register GPIOD and swap Pinctrl profiles Lee Jones
2017-01-24 22:00 ` kbuild test robot
2017-01-25 11:24 ` [STLinux Kernel] " Peter Griffin
2017-01-24 13:43 ` [PATCH 5/8] ARM: dts: STiH410-b2260: Identify the UART RTS line Lee Jones
2017-01-24 13:43 ` [PATCH 6/8] ARM: dts: STiH407-pinctrl: Add Pinctrl group for HW flow-control Lee Jones
2017-01-25 11:01 ` [STLinux Kernel] " Peter Griffin
2017-01-24 13:43 ` [PATCH 7/8] ARM: dts: STiH407-family: Use new Pinctrl groups Lee Jones
2017-01-25 11:54 ` [STLinux Kernel] " Peter Griffin
2017-01-27 11:03 ` Lee Jones
2017-01-27 11:29 ` Lee Jones
2017-01-24 13:43 ` [PATCH 8/8] ARM: dts: STiH407-family: Enable HW flow-control Lee Jones
2017-01-25 10:59 ` [STLinux Kernel] " Peter Griffin
2017-01-25 11:40 ` Peter Griffin
2017-01-27 11:33 ` Lee Jones
2017-01-27 11:32 ` Lee Jones
2017-01-25 10:07 ` [PATCH 0/8] serial: st-asc: Allow handling of RTS line Greg KH
2017-01-25 15:35 ` Lee Jones
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