Re: [PATCH v1 6/6] platform/chrome: Check the USB PD feature before creating a charger

[Lee Jones <lee.jones@linaro.org>]

On Fri, 05 Feb 2016, Tomeu Vizoso wrote:

> From: Vincent Palatin <vpalatin@chromium.org>
> 
> Use the EC_CMD_GET_FEATURES message to check the supported features for
> each MCU before instantied a USB-PD charger.
> 
> Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
> [tomeu: adapted to changes in mainline]
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
> 
> ---
> 
>  drivers/platform/chrome/cros_ec_dev.c | 40 ++++++++++++++++-
>  include/linux/mfd/cros_ec.h           |  1 +
>  include/linux/mfd/cros_ec_commands.h  | 84 +++++++++++++++++++++++++++++++++++

Acked-by: Lee Jones <lee.jones@linaro.org>

>  3 files changed, 124 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c
> index 7a97cd313c68..1995cccfc59c 100644
> --- a/drivers/platform/chrome/cros_ec_dev.c
> +++ b/drivers/platform/chrome/cros_ec_dev.c
> @@ -87,6 +87,41 @@ exit:
>  	return ret;
>  }
>  
> +static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
> +{
> +	struct cros_ec_command *msg;
> +	int ret;
> +
> +	if (ec->features[0] == -1U && ec->features[1] == -1U) {
> +		/* features bitmap not read yet */
> +
> +		msg = kmalloc(sizeof(*msg) + sizeof(ec->features), GFP_KERNEL);
> +		if (!msg)
> +			return -ENOMEM;
> +
> +		msg->version = 0;
> +		msg->command = EC_CMD_GET_FEATURES + ec->cmd_offset;
> +		msg->insize = sizeof(ec->features);
> +		msg->outsize = 0;
> +
> +		ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
> +		if ((ret < 0) || msg->result != EC_RES_SUCCESS) {
> +			dev_warn(ec->dev, "cannot get EC features: %d/%d\n",
> +				 ret, msg->result);
> +			memset(ec->features, 0, sizeof(ec->features));
> +		}
> +
> +		memcpy(ec->features, msg->data, sizeof(ec->features));
> +
> +		dev_dbg(ec->dev, "EC features %08x %08x\n",
> +			ec->features[0], ec->features[1]);
> +
> +		kfree(msg);
> +	}
> +
> +	return ec->features[feature / 32] & EC_FEATURE_MASK_0(feature);
> +}
> +
>  static int cros_ec_has_cmd_usb_pd_ports(struct cros_ec_dev *ec)
>  {
>  	struct cros_ec_command *msg;
> @@ -255,6 +290,8 @@ static int ec_device_probe(struct platform_device *pdev)
>  	ec->ec_dev = dev_get_drvdata(dev->parent);
>  	ec->dev = dev;
>  	ec->cmd_offset = ec_platform->cmd_offset;
> +	ec->features[0] = -1U; /* Not cached yet */
> +	ec->features[1] = -1U; /* Not cached yet */
>  	device_initialize(&ec->class_dev);
>  	cdev_init(&ec->cdev, &fops);
>  
> @@ -293,7 +330,8 @@ static int ec_device_probe(struct platform_device *pdev)
>  	}
>  
>  	/* check whether this EC instance has the PD charge manager */
> -	if (cros_ec_has_cmd_usb_pd_ports(ec)) {
> +	if (cros_ec_check_features(ec, EC_FEATURE_USB_PD) ||
> +	    cros_ec_has_cmd_usb_pd_ports(ec)) {
>  		retval = cros_ec_usb_pd_charger_register(dev);
>  		if (retval) {
>  			dev_err(dev, "failed to add usb-pd-charger device\n");
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index 543191f493a9..02ad92572d5a 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -193,6 +193,7 @@ struct cros_ec_dev {
>  	struct cros_ec_device *ec_dev;
>  	struct device *dev;
>  	u16 cmd_offset;
> +	u32 features[2];
>  };
>  
>  /**
> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
> index 4f056d2747ff..cc3a4b1b19e8 100644
> --- a/include/linux/mfd/cros_ec_commands.h
> +++ b/include/linux/mfd/cros_ec_commands.h
> @@ -716,6 +716,90 @@ struct ec_response_get_set_value {
>  /* More than one command can use these structs to get/set paramters. */
>  #define EC_CMD_GSV_PAUSE_IN_S5	0x0c
>  
> +/*****************************************************************************/
> +/* List the features supported by the firmware */
> +#define EC_CMD_GET_FEATURES  0x0d
> +
> +/* Supported features */
> +enum ec_feature_code {
> +	/*
> +	 * This image contains a limited set of features. Another image
> +	 * in RW partition may support more features.
> +	 */
> +	EC_FEATURE_LIMITED = 0,
> +	/*
> +	 * Commands for probing/reading/writing/erasing the flash in the
> +	 * EC are present.
> +	 */
> +	EC_FEATURE_FLASH = 1,
> +	/*
> +	 * Can control the fan speed directly.
> +	 */
> +	EC_FEATURE_PWM_FAN = 2,
> +	/*
> +	 * Can control the intensity of the keyboard backlight.
> +	 */
> +	EC_FEATURE_PWM_KEYB = 3,
> +	/*
> +	 * Support Google lightbar, introduced on Pixel.
> +	 */
> +	EC_FEATURE_LIGHTBAR = 4,
> +	/* Control of LEDs  */
> +	EC_FEATURE_LED = 5,
> +	/* Exposes an interface to control gyro and sensors.
> +	 * The host goes through the EC to access these sensors.
> +	 * In addition, the EC may provide composite sensors, like lid angle.
> +	 */
> +	EC_FEATURE_MOTION_SENSE = 6,
> +	/* The keyboard is controlled by the EC */
> +	EC_FEATURE_KEYB = 7,
> +	/* The AP can use part of the EC flash as persistent storage. */
> +	EC_FEATURE_PSTORE = 8,
> +	/* The EC monitors BIOS port 80h, and can return POST codes. */
> +	EC_FEATURE_PORT80 = 9,
> +	/*
> +	 * Thermal management: include TMP specific commands.
> +	 * Higher level than direct fan control.
> +	 */
> +	EC_FEATURE_THERMAL = 10,
> +	/* Can switch the screen backlight on/off */
> +	EC_FEATURE_BKLIGHT_SWITCH = 11,
> +	/* Can switch the wifi module on/off */
> +	EC_FEATURE_WIFI_SWITCH = 12,
> +	/* Monitor host events, through for example SMI or SCI */
> +	EC_FEATURE_HOST_EVENTS = 13,
> +	/* The EC exposes GPIO commands to control/monitor connected devices. */
> +	EC_FEATURE_GPIO = 14,
> +	/* The EC can send i2c messages to downstream devices. */
> +	EC_FEATURE_I2C = 15,
> +	/* Command to control charger are included */
> +	EC_FEATURE_CHARGER = 16,
> +	/* Simple battery support. */
> +	EC_FEATURE_BATTERY = 17,
> +	/*
> +	 * Support Smart battery protocol
> +	 * (Common Smart Battery System Interface Specification)
> +	 */
> +	EC_FEATURE_SMART_BATTERY = 18,
> +	/* EC can dectect when the host hangs. */
> +	EC_FEATURE_HANG_DETECT = 19,
> +	/* Report power information, for pit only */
> +	EC_FEATURE_PMU = 20,
> +	/* Another Cros EC device is present downstream of this one */
> +	EC_FEATURE_SUB_MCU = 21,
> +	/* Support USB Power delivery (PD) commands */
> +	EC_FEATURE_USB_PD = 22,
> +	/* Control USB multiplexer, for audio through USB port for instance. */
> +	EC_FEATURE_USB_MUX = 23,
> +	/* Motion Sensor code has an internal software FIFO */
> +	EC_FEATURE_MOTION_SENSE_FIFO = 24,
> +};
> +
> +#define EC_FEATURE_MASK_0(event_code) (1UL << (event_code % 32))
> +#define EC_FEATURE_MASK_1(event_code) (1UL << (event_code - 32))
> +struct ec_response_get_features {
> +	uint32_t flags[2];
> +} __packed;
>  
>  /*****************************************************************************/
>  /* Flash commands */

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