Re: [PATCH v3 2/4] drm/i915: Add lspcon support for I915 driver

["Sharma, Shashank" <shashank.sharma@intel.com>]

Regards

Shashank


On 8/11/2016 12:33 PM, Ville Syrjälä wrote:
> On Tue, Jul 05, 2016 at 06:35:48PM +0530, Shashank Sharma wrote:
>> This patch adds a new file, to accommodate lspcon support
>> for I915 driver. These functions probe, detect, initialize
>> and configure an on-board lspcon device during the driver
>> init time.
>>
>> Also, this patch adds a small structure for lspcon device,
>> which will provide the runtime status of the device.
>>
>> V2: addressed ville's review comments
>> - Clean the leftover macros from previous patch set
>>
>> V3: Rebase
>>
>> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
>> Signed-off-by: Akashdeep Sharma <akashdeep.sharma@intel.com>
>> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> ---
>>   drivers/gpu/drm/i915/Makefile       |   1 +
>>   drivers/gpu/drm/i915/intel_drv.h    |  13 +++-
>>   drivers/gpu/drm/i915/intel_lspcon.c | 145 ++++++++++++++++++++++++++++++++++++
>>   3 files changed, 158 insertions(+), 1 deletion(-)
>>   create mode 100644 drivers/gpu/drm/i915/intel_lspcon.c
>>
>> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
>> index 618293c..64cd373 100644
>> --- a/drivers/gpu/drm/i915/Makefile
>> +++ b/drivers/gpu/drm/i915/Makefile
>> @@ -95,6 +95,7 @@ i915-y += dvo_ch7017.o \
>>   	  intel_dvo.o \
>>   	  intel_hdmi.o \
>>   	  intel_i2c.o \
>> +	  intel_lspcon.o \
>>   	  intel_lvds.o \
>>   	  intel_panel.o \
>>   	  intel_sdvo.o \
>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>> index e6a24d2..e6982cf 100644
>> --- a/drivers/gpu/drm/i915/intel_drv.h
>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>> @@ -922,12 +922,19 @@ struct intel_dp {
>>   	bool compliance_test_active;
>>   };
>>   
>> +struct intel_lspcon {
>> +	bool active;
>> +	enum drm_lspcon_mode mode_of_op;
> I'd call this just 'mode'
I dont want reader to get confused this with a videomode, so made it 
more clear :)
Do you think we can keep it this way ?
>> +	struct drm_dp_aux *aux;
>> +};
>> +
>>   struct intel_digital_port {
>>   	struct intel_encoder base;
>>   	enum port port;
>>   	u32 saved_port_bits;
>>   	struct intel_dp dp;
>>   	struct intel_hdmi hdmi;
>> +	struct intel_lspcon lspcon;
>>   	enum irqreturn (*hpd_pulse)(struct intel_digital_port *, bool);
>>   	bool release_cl2_override;
>>   	uint8_t max_lanes;
>> @@ -1478,7 +1485,6 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>>   			       struct intel_crtc_state *pipe_config);
>>   void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi *hdmi, bool enable);
>>   
>> -
>>   /* intel_lvds.c */
>>   void intel_lvds_init(struct drm_device *dev);
>>   struct intel_encoder *intel_get_lvds_encoder(struct drm_device *dev);
>> @@ -1779,4 +1785,9 @@ int intel_color_check(struct drm_crtc *crtc, struct drm_crtc_state *state);
>>   void intel_color_set_csc(struct drm_crtc_state *crtc_state);
>>   void intel_color_load_luts(struct drm_crtc_state *crtc_state);
>>   
>> +/* intel_lspcon.c */
>> +bool lspcon_init(struct intel_digital_port *intel_dig_port);
>> +enum drm_connector_status
>> +lspcon_ls_mode_detect(struct drm_connector *connector, bool force);
>> +bool is_lspcon_active(struct intel_digital_port *dig_port);
>>   #endif /* __INTEL_DRV_H__ */
>> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
>> new file mode 100644
>> index 0000000..fdeff71
>> --- /dev/null
>> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
>> @@ -0,0 +1,145 @@
>> +/*
>> + * Copyright © 2016 Intel Corporation
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> + * copy of this software and associated documentation files (the "Software"),
>> + * to deal in the Software without restriction, including without limitation
>> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice (including the next
>> + * paragraph) shall be included in all copies or substantial portions of the
>> + * Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
>> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
>> + * DEALINGS IN THE SOFTWARE.
>> + *
>> + *
>> + */
>> +#include <drm/drm_edid.h>
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_dp_dual_mode_helper.h>
>> +#include "intel_drv.h"
>> +
>> +bool is_lspcon_active(struct intel_digital_port *dig_port)
>> +{
>> +	return dig_port->lspcon.active;
>> +}
> unused -> kill it
>
> In fact the whole lspcon.active flags seems pretty pointless, so I'd
> just kill that too.
Please note that, I tried to address both motherboard-down mode as well 
as adapter-mode LSPCON
in this design. In case of adapter mode lspcon, we will need this.
>
>> +
>> +enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
>> +{
>> +	enum drm_lspcon_mode current_mode = DRM_LSPCON_MODE_INVALID;
>> +	struct i2c_adapter *adapter = &lspcon->aux->ddc;
>> +
>> +	if (drm_lspcon_get_mode(adapter, &current_mode))
>> +		DRM_ERROR("Error reading LSPCON mode\n");
>> +	else
>> +		DRM_DEBUG_KMS("Current LSPCON mode %s\n",
>> +			current_mode == DRM_LSPCON_MODE_PCON ? "PCON" : "LS");
>> +	return current_mode;
>> +}
> I was going to suggest killing this one too, but I guess the debug
> output might be useful. Make it static at least.
Sure, will make it static. Also we have a plan to expose one DRM 
property to handle adapter mode lspcon
at that time this will help.
>> +
>> +int lspcon_change_mode(struct intel_lspcon *lspcon,
>> +	enum drm_lspcon_mode mode, bool force)
> static
Sure.
>
>> +{
>> +	int err;
>> +	enum drm_lspcon_mode current_mode;
>> +	struct i2c_adapter *adapter = &lspcon->aux->ddc;
>> +
>> +	err = drm_lspcon_get_mode(adapter, &current_mode);
>> +	if (err) {
>> +		DRM_ERROR("Error reading LSPCON mode\n");
>> +		return err;
>> +	}
>> +
>> +	if (current_mode == mode && !force) {
>> +		DRM_DEBUG_KMS("Current mode = desired LSPCON mode\n");
>> +		return 0;
>> +	}
> We always call this with force==true, so it looks like a pointless
> parameter. Also if force==true always, it doesn't necessary to even
> query the current mode. Oh and I think we've already queried the mode
> when this gets called.
As mentioned, I wanted to keep the scope of switching lspcon modes, in 
the design infrastructure.
So I kept these things as possibility.

IF we create a DRM property to query LSPCON mode, that get_property 
function will call this
function with force = false, coz for this query we dont want to probe 
the HW again.
>> +
>> +	err = drm_lspcon_set_mode(adapter, mode);
>> +	if (err < 0) {
>> +		DRM_ERROR("LSPCON mode change failed\n");
>> +		return err;
>> +	}
>> +
>> +	lspcon->mode_of_op = mode;
>> +	DRM_DEBUG_KMS("LSPCON mode changed done\n");
>> +	return 0;
>> +}
>> +
>> +bool lspcon_detect_identifier(struct intel_lspcon *lspcon)
> static
got it.
>
>> +{
>> +	enum drm_dp_dual_mode_type adaptor_type;
>> +	struct i2c_adapter *adapter = &lspcon->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_LSPCON) {
>> +		DRM_DEBUG_KMS("No LSPCON detected, found %s\n",
>> +			drm_dp_get_dual_mode_type_name(adaptor_type));
>> +		return false;
>> +	}
>> +
>> +	/* Yay ... got a LSPCON device */
>> +	DRM_DEBUG_KMS("LSPCON detected\n");
>> +	return true;
>> +}
> This is small function and called only once, so I'd just inline it into
> the caller actually.
Can be done, but the caller is intelI_ddi_init, which I dont want to 
populate with lspcon specific code, when we have a separate file
for lspcon. Do you think its a good idea ? or you prefer to have that in 
ddi_init only ?
>> +
>> +enum drm_lspcon_mode lspcon_probe(struct intel_lspcon *lspcon)
> static
Got it.
>
>> +{
>> +
>> +	/* Detect a valid lspcon adaptor */
>> +	if (!lspcon_detect_identifier(lspcon)) {
>> +		DRM_DEBUG_KMS("No LSPCON identifier found\n");
>> +		return false;
>> +	}
>> +
>> +	/* Get LSPCON's mode of operation */
>> +	lspcon->mode_of_op = lspcon_get_current_mode(lspcon);
>> +	lspcon->active = true;
>> +	return true;
>> +}
>> +
>> +bool lspcon_init(struct intel_digital_port *intel_dig_port)
>> +{
>> +	struct intel_dp *dp = &intel_dig_port->dp;
>> +	struct intel_lspcon *lspcon = &intel_dig_port->lspcon;
>> +	struct drm_device *dev = intel_dig_port->base.base.dev;
>> +
>> +	if (!IS_GEN9(dev)) {
>> +		DRM_ERROR("LSPCON is supported on GEN9 only\n");
>> +		return false;
>> +	}
> Just remove this check? If it's not present, we won't detect it.
Faulty VBT ? Just being paranoid.
>> +
>> +	lspcon->active = false;
>> +	lspcon->mode_of_op = DRM_LSPCON_MODE_INVALID;
>> +	lspcon->aux = &dp->aux;
>> +
>> +	if (!lspcon_probe(lspcon)) {
>> +		DRM_ERROR("Failed to probe lspcon\n");
>> +		return false;
>> +	}
>> +
>> +	/*
>> +	* In the SW state machine, lets Put LSPCON in PCON mode only.
>> +	* In this way, it will work with both HDMI 1.4 sinks as well as HDMI
>> +	* 2.0 sinks.
>> +	*/
>> +	if (lspcon->active && lspcon->mode_of_op != DRM_LSPCON_MODE_PCON) {
>> +		if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON,
>> +			true) < 0) {
> indent fail.
same as previous.

Regards
Shashank
>> +			DRM_ERROR("LSPCON mode change to PCON failed\n");
>> +			return false;
>> +		}
>> +	}
>> +
>> +	DRM_DEBUG_KMS("Success: LSPCON init\n");
>> +	return true;
>> +}
>> -- 
>> 1.9.1

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