From: Drew Fustini <drew@beagleboard.org> To: Trent Piepho <tpiepho@gmail.com> Cc: linux-arm-kernel@lists.infradead.org, Tony Lindgren <tony@atomide.com>, Rob Herring <robh+dt@kernel.org>, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, Linus Walleij <linus.walleij@linaro.org>, Haojian Zhuang <haojian.zhuang@linaro.org>, devicetree@vger.kernel.org, bcousson@baylibre.com, Jason Kridner <jkridner@beagleboard.org>, Robert Nelson <robertcnelson@gmail.com> Subject: Re: [PATCH v4 1/2] pinctrl: single: parse #pinctrl-cells = 2 Date: Sun, 13 Sep 2020 21:42:33 +0200 [thread overview] Message-ID: <20200913194233.GA1955808@x1> (raw) In-Reply-To: <3139716.CMS8C0sQ7x@zen.local> On Tue, Sep 08, 2020 at 04:52:58PM -0700, Trent Piepho wrote: > On Tuesday, June 30, 2020 6:33:19 PM PDT Drew Fustini wrote: > > If "pinctrl-single,pins" has 3 arguments (offset, conf, mux), then > > pcs_parse_one_pinctrl_entry() does an OR operation on conf and mux to > > get the value to store in the register. > > > > - vals[found].val = pinctrl_spec.args[1]; > > + > > + switch (pinctrl_spec.args_count) { > > + case 2: > > + vals[found].val = pinctrl_spec.args[1]; > > + break; > > + case 3: > > + vals[found].val = (pinctrl_spec.args[1] | > pinctrl_spec.args[2]); > > + break; > > + } > > > > dev_dbg(pcs->dev, "%pOFn index: 0x%x value: 0x%x\n", > > pinctrl_spec.np, offset, > pinctrl_spec.args[1]); > > If #pinctrl-cells value is greater than 2, nothing will set vals[found].val to > anything other than zero (from when it's calloc'ed) and the pinctrl will > silently be programmed to zero. If #pinctrl-cells is 3, then it will be: vals[found].val = (pinctrl_spec.args[1] | pinctrl_spec.args[2]); Do you mean if #pinctrl-cells is great than 3 then it will just have a default value of zero? That does appear to be the case and is probably not the behavior we want. Thank you for pointing this out. Earlier, there is a check to make sure there are at least 2 arguments: if (pinctrl_spec.args_count < 2) { dev_err(pcs->dev, "invalid args_count for spec: %i\n", pinctrl_spec.args_count); break; } I'll submit a patch where the upper bound is also checked: if (pinctrl_spec.args_count < 2 || pinctrl_spec.args_count > 3) { dev_err(pcs->dev, "invalid args_count for spec: %i\n", pinctrl_spec.args_count); break; } > The debug printout was not change to print vals[found].val, so it will > continue to print the value of the 2nd cell. Thank you for pointing this out. Yes, this is an oversight and I will submit a patch. > The result is that a #pinctrl-cells of 3 will produce no warning or error, > program the pinctrl to zero, whilst at the same time emit debug log messages > that it is programming the expected values. > > The device tree documentation still states that #pinctrl-cells must be 1 when > using pinctrl-single,pins. This new special case of ORing two values is not > documented. This is a good point, too. I will make a patch to update the documentation. -Drew
WARNING: multiple messages have this Message-ID (diff)
From: Drew Fustini <drew@beagleboard.org> To: Trent Piepho <tpiepho@gmail.com> Cc: devicetree@vger.kernel.org, Jason Kridner <jkridner@beagleboard.org>, Tony Lindgren <tony@atomide.com>, Linus Walleij <linus.walleij@linaro.org>, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, Rob Herring <robh+dt@kernel.org>, Haojian Zhuang <haojian.zhuang@linaro.org>, bcousson@baylibre.com, linux-omap@vger.kernel.org, Robert Nelson <robertcnelson@gmail.com>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v4 1/2] pinctrl: single: parse #pinctrl-cells = 2 Date: Sun, 13 Sep 2020 21:42:33 +0200 [thread overview] Message-ID: <20200913194233.GA1955808@x1> (raw) In-Reply-To: <3139716.CMS8C0sQ7x@zen.local> On Tue, Sep 08, 2020 at 04:52:58PM -0700, Trent Piepho wrote: > On Tuesday, June 30, 2020 6:33:19 PM PDT Drew Fustini wrote: > > If "pinctrl-single,pins" has 3 arguments (offset, conf, mux), then > > pcs_parse_one_pinctrl_entry() does an OR operation on conf and mux to > > get the value to store in the register. > > > > - vals[found].val = pinctrl_spec.args[1]; > > + > > + switch (pinctrl_spec.args_count) { > > + case 2: > > + vals[found].val = pinctrl_spec.args[1]; > > + break; > > + case 3: > > + vals[found].val = (pinctrl_spec.args[1] | > pinctrl_spec.args[2]); > > + break; > > + } > > > > dev_dbg(pcs->dev, "%pOFn index: 0x%x value: 0x%x\n", > > pinctrl_spec.np, offset, > pinctrl_spec.args[1]); > > If #pinctrl-cells value is greater than 2, nothing will set vals[found].val to > anything other than zero (from when it's calloc'ed) and the pinctrl will > silently be programmed to zero. If #pinctrl-cells is 3, then it will be: vals[found].val = (pinctrl_spec.args[1] | pinctrl_spec.args[2]); Do you mean if #pinctrl-cells is great than 3 then it will just have a default value of zero? That does appear to be the case and is probably not the behavior we want. Thank you for pointing this out. Earlier, there is a check to make sure there are at least 2 arguments: if (pinctrl_spec.args_count < 2) { dev_err(pcs->dev, "invalid args_count for spec: %i\n", pinctrl_spec.args_count); break; } I'll submit a patch where the upper bound is also checked: if (pinctrl_spec.args_count < 2 || pinctrl_spec.args_count > 3) { dev_err(pcs->dev, "invalid args_count for spec: %i\n", pinctrl_spec.args_count); break; } > The debug printout was not change to print vals[found].val, so it will > continue to print the value of the 2nd cell. Thank you for pointing this out. Yes, this is an oversight and I will submit a patch. > The result is that a #pinctrl-cells of 3 will produce no warning or error, > program the pinctrl to zero, whilst at the same time emit debug log messages > that it is programming the expected values. > > The device tree documentation still states that #pinctrl-cells must be 1 when > using pinctrl-single,pins. This new special case of ORing two values is not > documented. This is a good point, too. I will make a patch to update the documentation. -Drew _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-09-13 19:42 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-01 1:33 [PATCH v4 0/2] pinctrl: single: support #pinctrl-cells = 2 Drew Fustini 2020-07-01 1:33 ` Drew Fustini 2020-07-01 1:33 ` [PATCH v4 1/2] pinctrl: single: parse " Drew Fustini 2020-07-01 1:33 ` Drew Fustini 2020-09-08 23:52 ` Trent Piepho 2020-09-08 23:52 ` Trent Piepho 2020-09-13 19:42 ` Drew Fustini [this message] 2020-09-13 19:42 ` Drew Fustini 2020-09-13 23:27 ` Drew Fustini 2020-09-13 23:27 ` Drew Fustini 2020-07-01 1:33 ` [PATCH v4 2/2] ARM: dts: am33xx-l4: change #pinctrl-cells from 1 to 2 Drew Fustini 2020-07-01 1:33 ` Drew Fustini 2020-09-09 0:34 ` Trent Piepho 2020-09-09 0:34 ` Trent Piepho 2021-01-15 18:02 ` Emmanuel Vadot 2021-01-15 18:02 ` Emmanuel Vadot 2021-01-15 21:40 ` Drew Fustini 2021-01-15 21:40 ` Drew Fustini 2021-01-18 7:41 ` Tony Lindgren 2021-01-18 7:41 ` Tony Lindgren 2020-07-02 17:36 ` [PATCH v4 0/2] pinctrl: single: support #pinctrl-cells = 2 Tony Lindgren 2020-07-02 17:36 ` Tony Lindgren 2020-07-05 9:01 ` Haojian Zhuang 2020-07-05 9:01 ` Haojian Zhuang 2020-07-07 10:59 ` Linus Walleij 2020-07-07 10:59 ` Linus Walleij 2020-07-07 11:02 ` Drew Fustini 2020-07-07 11:02 ` Drew Fustini 2020-07-11 21:12 ` Linus Walleij 2020-07-11 21:12 ` Linus Walleij
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