linux-kernel - Re: [PATCH v3 2/4] mfd: cros_ec: add EC

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Message-ID: <20160628153140.GD29166@dell>
Date:	Tue, 28 Jun 2016 16:31:40 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Brian Norris <briannorris@...omium.org>
Cc:	Thierry Reding <thierry.reding@...il.com>,
	Olof Johansson <olof@...om.net>, linux-kernel@...r.kernel.org,
	Doug Anderson <dianders@...omium.org>,
	Brian Norris <computersforpeace@...il.com>,
	linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
	Boris Brezillon <boris.brezillon@...e-electrons.com>,
	Stephen Barber <smbarber@...omium.org>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Benson Leung <bleung@...omium.org>,
	Enric Balletbo <enric.balletbo@...labora.co.uk>,
	Randall Spangler <rspangler@...omium.org>,
	Shawn Nematbakhsh <shawnn@...omium.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Todd Broch <tbroch@...omium.org>,
	Gwendal Grignou <gwendal@...omium.org>,
	Tomeu Vizoso <tomeu.vizoso@...labora.com>
Subject: Re: [PATCH v3 2/4] mfd: cros_ec: add EC_PWM function definitions

On Fri, 17 Jun 2016, Brian Norris wrote:

> The EC_CMD_PWM_{GET,SET}_DUTY commands allow us to control a PWM that is
> attached to the EC, rather than the main host SoC. The API provides
> functionality-based (e.g., keyboard light, backlight) or index-based
> 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 <briannorris@...omium.org>
> ---
> v3:
>  * convert from 65535 to 0xffff
> 
> v2:
>  * no changes
> ---
>  include/linux/mfd/cros_ec_commands.h | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)

For my own reference:
  Acked-by: Lee Jones <lee.jones@...aro.org>
  
> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
> index 13b630c10d4c..7e7a8d4b4551 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, 0xffff = 100% */
> +#define EC_PWM_MAX_DUTY 0xffff
> +
> +enum ec_pwm_type {
> +	/* All types, indexed by board-specific enum pwm_channel */
> +	EC_PWM_TYPE_GENERIC = 0,
> +	/* Keyboard backlight */
> +	EC_PWM_TYPE_KB_LIGHT,
> +	/* Display backlight */
> +	EC_PWM_TYPE_DISPLAY_LIGHT,
> +	EC_PWM_TYPE_COUNT,
> +};
> +
> +struct ec_params_pwm_set_duty {
> +	uint16_t duty;     /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
> +	uint8_t pwm_type;  /* ec_pwm_type */
> +	uint8_t index;     /* Type-specific index, or 0 if unique */
> +} __packed;
> +
> +#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;
> +
> +struct ec_response_pwm_get_duty {
> +	uint16_t duty;     /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
> +} __packed;
> +
>  /*****************************************************************************/
>  /*
>   * Lightbar commands. This looks worse than it is. Since we only use one HOST

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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