From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laxman Dewangan Subject: Re: [PATCH V2 2/2] pinctrl: tegra: Add driver to configure voltage and power of io pads Date: Mon, 21 Nov 2016 15:06:05 +0530 Message-ID: <5832C005.3070104@nvidia.com> References: <1478696782-11657-1-git-send-email-ldewangan@nvidia.com> <1478696782-11657-3-git-send-email-ldewangan@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jon Hunter , linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org, thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Cc: gnurou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, yamada.masahiro-uWyLwvC0a2jby3iVrkZq2A@public.gmane.org, linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org Hi Jon, I will update the patch per your comment. Here is answer for some of the query. Thanks, Laxman On Tuesday 15 November 2016 08:37 PM, Jon Hunter wrote: > On 09/11/16 13:06, Laxman Dewangan wrote: >> +/** >> + * Macro for 1.8V, keep 200mV as tolerance for deciding that >> + * IO pads should be set for 3.3V (high voltage) or 1.8V. >> + */ >> +#define TEGRA_IO_PAD_1800000UV_UPPER_LIMIT 2000000 > Is there a reference we could add for the source of this information? I had a discussion with the ASIC on this and as per them 1.8 V nominal is (1.62V, 1.98V) 3.3 V nominal is (2.97V,3.63V) I am working with them to update the TRM document but we can assume that this information will be there in TRM. >> + const struct pinctrl_pin_desc *pins_desc; >> + int num_pins_desc; >> +}; >> + >> +struct tegra_io_pads_regulator_info { >> + struct device *dev; >> + const struct tegra_io_pads_cfg_info *pads_cfg; >> + struct regulator *regulator; >> + struct notifier_block regulator_nb; >> +}; > Is this struct necessary? Seems to be a lot of duplicated information > from the other structs. Why not add the regulator and regulator_nb to > the main struct? OK, not all io_pads have a regulator but you are only > saving one pointer. Yes, some of IO pads support multi-voltage. > > + if ((vdata->old_uV > TEGRA_IO_PAD_1800000UV_UPPER_LIMIT) && > + (vdata->min_uV <= TEGRA_IO_PAD_1800000UV_UPPER_LIMIT)) > + break; > The data-sheet for Tegra210 only lists 1.8V or 3.3V as supported > options. Do we need to support a range? Or does the h/w support a range > of voltages? I am just wondering why we cannot check explicitly for 1.8V > or 3.3V and treat anything else as an error. Two voltage level, not range.