Re: [PATCH 10/12] drm/i915: Add lspcon core functions

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Apr 04, 2016 at 05:31:46PM +0530, Shashank Sharma wrote:
> This patch adds lspcon's internal functions, which work
> on the probe layer, and indicate the working status of
> lspcon, which are mostly:
> 
> probe: A lspcon device is probed only once, during boot
> time, as its always present with the device, next to port.
> So the i2c_over_aux channel is alwyas read/writeable if DC is
> powered on. If VBT says that this port contains lspcon, we
> check and probe the HW to verify and initialize it.
> 
> get_mode: This function indicates the current mode of operation
> of lspcon (ls or pcon mode)
> 
> change_mode: This function can change the lspcon's mode of
> operation to desired mode.
> 
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> Signed-off-by: Akashdeep Sharma <Akashdeep.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_lspcon.c | 145 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 145 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> index c3c1cd2..617fe3f 100644
> --- a/drivers/gpu/drm/i915/intel_lspcon.c
> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
> @@ -61,6 +61,144 @@ static struct intel_lspcon
>  	return enc_to_lspcon(&intel_attached_encoder(connector)->base);
>  }
>  
> +enum lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
> +{
> +	u8 data;
> +	int err = 0;
> +	struct intel_digital_port *dig_port = lspcon_to_dig_port(lspcon);
> +	struct i2c_adapter *adapter = &dig_port->dp.aux.ddc;
> +
> +	/* Read Status: i2c over aux */
> +	err = drm_dp_dual_mode_ioa_read(adapter, &data,
> +		LSPCON_MODE_CHECK_OFFSET, sizeof(data));
> +	if (err < 0) {
> +		DRM_ERROR("LSPCON read mode ioa (0x80, 0x41) failed\n");
> +		return lspcon_mode_invalid;
> +	}
> +
> +	DRM_DEBUG_DRIVER("LSPCON mode (0x80, 0x41) = %x\n", (unsigned int)data);
> +	return data & LSPCON_MODE_MASK ? lspcon_mode_pcon : lspcon_mode_ls;
> +}
> +
> +int lspcon_change_mode(struct intel_lspcon *lspcon,
> +	enum lspcon_mode mode, bool force)
> +{
> +	u8 data;
> +	int err;
> +	int time_out = 200;
> +	enum lspcon_mode current_mode;
> +	struct intel_digital_port *dig_port = lspcon_to_dig_port(lspcon);
> +
> +	current_mode = lspcon_get_current_mode(lspcon);
> +	if (current_mode == lspcon_mode_invalid) {
> +		DRM_ERROR("Failed to get current LSPCON mode\n");
> +		return -EFAULT;
> +	}
> +
> +	if (current_mode == mode && !force) {
> +		DRM_DEBUG_DRIVER("Current mode = desired LSPCON mode\n");
> +		return 0;
> +	}
> +
> +	if (mode == lspcon_mode_ls)
> +		data = ~LSPCON_MODE_MASK;
> +	else
> +		data = LSPCON_MODE_MASK;
> +
> +	/* Change mode */
> +	err = drm_dp_dual_mode_ioa_write(&dig_port->dp.aux.ddc, &data,
> +			LSPCON_MODE_CHANGE_OFFSET, sizeof(data));
> +	if (err < 0) {
> +		DRM_ERROR("LSPCON mode change failed\n");
> +		return err;
> +	}
> +
> +	/*
> +	* Confirm mode change by reading the status bit.
> +	* Sometimes, it takes a while to change the mode,
> +	* so wait and retry until time out or done.
> +	*/
> +	while (time_out) {
> +		current_mode = lspcon_get_current_mode(lspcon);
> +		if (current_mode != mode) {
> +			mdelay(10);
> +			time_out -= 10;
> +		} else {
> +			lspcon->mode_of_op = mode;
> +			DRM_DEBUG_DRIVER("LSPCON mode changed to %s\n",
> +				mode == lspcon_mode_ls ? "LS" : "PCON");
> +			return 0;
> +		}
> +	}
> +
> +	DRM_ERROR("LSPCON mode change timed out\n");
> +	return -EFAULT;
> +}

I think we probably want to put most of this stuff into the helper. We
already have the LSPCON identification there, so having a few helpers
to set/get the ls vs. pconn mode would seem appropriate.

> +
> +bool lspcon_detect_identifier(struct intel_lspcon *lspcon)
> +{
> +	enum drm_dp_dual_mode_type adaptor_type;
> +	struct intel_digital_port *dig_port = lspcon_to_dig_port(lspcon);
> +	struct i2c_adapter *adapter = &dig_port->dp.aux.ddc;
> +
> +	/* Lets probe the adaptor and check its type */
> +	adaptor_type = drm_dp_dual_mode_detect(adapter);
> +	if (adaptor_type != DRM_DP_DUAL_MODE_TYPE2_LSPCON) {
> +		DRM_DEBUG_DRIVER("No LSPCON detected, found %s\n",
> +			drm_dp_get_dual_mode_type_name(adaptor_type));
> +		return false;
> +	}
> +
> +	/* Yay ... got a LSPCON device */
> +	DRM_DEBUG_DRIVER("LSPCON detected\n");
> +	return true;
> +}
> +
> +enum lspcon_mode lspcon_probe(struct intel_lspcon *lspcon)
> +{
> +	enum lspcon_mode current_mode;
> +
> +	/* Detect a valid lspcon */
> +	if (!lspcon_detect_identifier(lspcon)) {
> +		DRM_DEBUG_DRIVER("Failed to find LSPCON identifier\n");
> +		return false;
> +	}
> +
> +	/* LSPCON's mode of operation */
> +	current_mode = lspcon_get_current_mode(lspcon);
> +	if (current_mode == lspcon_mode_invalid) {
> +		DRM_ERROR("Failed to read LSPCON mode\n");
> +		return false;
> +	}
> +
> +	/* All is well */
> +	lspcon->mode_of_op = current_mode;
> +	lspcon->active = true;
> +	return current_mode;
> +}
> +
> +bool lspcon_device_init(struct intel_lspcon *lspcon)
> +{
> +
> +	/* Lets check LSPCON now, probe the HW status */
> +	lspcon->active = false;
> +	lspcon->mode_of_op = lspcon_mode_invalid;
> +	if (!lspcon_probe(lspcon)) {
> +		DRM_ERROR("Failed to probe lspcon");
> +		return false;
> +	}
> +
> +	/* We wish to keep LSPCON in LS mode */
> +	if (lspcon->active && lspcon->mode_of_op != lspcon_mode_ls) {
> +		if (lspcon_change_mode(lspcon, lspcon_mode_ls, true) < 0) {
> +			DRM_ERROR("LSPCON mode change to LS failed\n");
> +			return false;
> +		}
> +	}
> +	DRM_DEBUG_DRIVER("LSPCON init success\n");
> +	return true;
> +}
> +
>  struct edid *lspcon_get_edid(struct intel_lspcon *lspcon, struct drm_connector
>  						*connector)
>  {
> @@ -233,6 +371,7 @@ int intel_lspcon_init_connector(struct intel_digital_port *intel_dig_port)
>  	struct intel_encoder *intel_encoder = &intel_dig_port->base;
>  	struct drm_device *dev = intel_encoder->base.dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_lspcon *lspcon = &intel_dig_port->lspcon;
>  	struct intel_connector *intel_connector;
>  	struct drm_connector *connector;
>  	enum port port = intel_dig_port->port;
> @@ -314,6 +453,12 @@ int intel_lspcon_init_connector(struct intel_digital_port *intel_dig_port)
>  		I915_WRITE(PEG_BAND_GAP_DATA, (temp & ~0xf) | 0xd);
>  	}
>  
> +	/* Now initialize the LSPCON device */
> +	if (!lspcon_device_init(lspcon)) {
> +		DRM_ERROR("LSPCON device init failed\n");
> +		goto fail;
> +	}
> +
>  	DRM_DEBUG_DRIVER("Success: LSPCON connector init\n");
>  	return 0;
>  
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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