From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v2 2/4] mfd: cros_ec: add EC_PWM function definitions Date: Fri, 17 Jun 2016 09:06:35 +0100 Message-ID: <20160617080635.GG21702@dell> References: <1464916904-37554-1-git-send-email-briannorris@chromium.org> <1464916904-37554-3-git-send-email-briannorris@chromium.org> <20160616153817.GD21702@dell> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Doug Anderson Cc: Brian Norris , Thierry Reding , Olof Johansson , "linux-kernel@vger.kernel.org" , Brian Norris , linux-pwm , "devicetree@vger.kernel.org" , Boris Brezillon , Stephen Barber , Javier Martinez Canillas , Benson Leung , Enric Balletbo , Randall Spangler , Shawn Nematbakhsh , Dmitry Torokhov , Todd Broch , Gwendal Grignou , Tomeu Vizoso List-Id: devicetree@vger.kernel.org On Thu, 16 Jun 2016, Doug Anderson wrote: > On Thu, Jun 16, 2016 at 8:38 AM, Lee Jones wro= te: > > On Thu, 02 Jun 2016, Brian Norris wrote: > > > >> The EC_CMD_PWM_{GET,SET}_DUTY commands allow us to control a PWM t= hat is > >> attached to the EC, rather than the main host SoC. The API provide= s > >> functionality-based (e.g., keyboard light, backlight) or index-bas= ed > >> addressing of the PWM(s). Duty cycles are represented by a 16-bit = value, > >> where 0 maps to 0% duty cycle and U16_MAX maps to 100%. The period > >> cannot be controlled. > >> > >> This command set is more generic than, e.g., > >> EC_CMD_PWM_{GET,SET}_KEYBOARD_BACKLIGHT and could possibly used to > >> replace it on future products. > >> > >> Let's update the command header to include the definitions. > >> > >> Signed-off-by: Brian Norris > >> --- > >> v2: no change > >> > >> include/linux/mfd/cros_ec_commands.h | 31 +++++++++++++++++++++++= ++++++++ > >> 1 file changed, 31 insertions(+) > >> > >> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/= mfd/cros_ec_commands.h > >> index 13b630c10d4c..d673575e0ada 100644 > >> --- a/include/linux/mfd/cros_ec_commands.h > >> +++ b/include/linux/mfd/cros_ec_commands.h > >> @@ -949,6 +949,37 @@ struct ec_params_pwm_set_fan_duty { > >> uint32_t percent; > >> } __packed; > >> > >> +#define EC_CMD_PWM_SET_DUTY 0x25 > >> +/* 16 bit duty cycle, 65535 =3D 100% */ > >> +#define EC_PWM_MAX_DUTY 65535 > > > > Any reason this isn't represented in hex, like we do normally? > > > >> +enum ec_pwm_type { > >> + /* All types, indexed by board-specific enum pwm_channel */ > >> + EC_PWM_TYPE_GENERIC =3D 0, > >> + /* Keyboard backlight */ > >> + EC_PWM_TYPE_KB_LIGHT, > >> + /* Display backlight */ > >> + EC_PWM_TYPE_DISPLAY_LIGHT, > >> + EC_PWM_TYPE_COUNT, > >> +}; > > > > Are these comments really necessary? I'd recommend that if your > > defines require comments, then they are not adequately named. In t= his > > case however, I'd suggest that they are and the comments are > > superfluous. > > > >> +struct ec_params_pwm_set_duty { > >> + uint16_t duty; /* Duty cycle, EC_PWM_MAX_DUTY =3D 100% *= / > >> + uint8_t pwm_type; /* ec_pwm_type */ > >> + uint8_t index; /* Type-specific index, or 0 if unique */ > >> +} __packed; > > > > Please use kerneldoc format. > > > >> +#define EC_CMD_PWM_GET_DUTY 0x26 > >> + > >> +struct ec_params_pwm_get_duty { > >> + uint8_t pwm_type; /* ec_pwm_type */ > >> + uint8_t index; /* Type-specific index, or 0 if unique */ > >> +} __packed; >=20 > Probably the reason for all of these non-kernel-isms is that this > isn't a kernel file. From the top of the file: >=20 > * NOTE: This file is copied verbatim from the ChromeOS EC Open Sourc= e > * project in an attempt to make future updates easy to make. >=20 > So the source of truth for this file is > . >=20 > Someone could probably submit a CL to that project to make it a littl= e > more kernel-ish and then we'd have to see if the EC team would accept > such changes... Hmmm... that kinda puts me in a difficult position. Do I except non-kernel code, which does not conform to our stands? Naturally I'd be happier if you could try to make the code more 'kernely'. The practices I mention above are still good ones, even if you're not writing kernel specific code. --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog