Re: [PATCH v6] drm: Helper for lspcon in drm_dp_dual_mode

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 17 Oct 2016, Shashank Sharma <shashank.sharma@intel.com> wrote:
> Readme: {
>  	This patch-series got approved in drm-intel mailing list already.
>  	Sending this one patch to dri-devel too, as this patch touches the
>  	drm layer dp_dual_mode_helper implementation. Plese provide an ack
>  	so that we can merge this in intel-gfx tree.
>  	The full patch series and review history at:
>  	https://patchwork.freedesktop.org/patch/115769/
> }
>
> This patch adds lspcon support in dp_dual_mode helper.
> lspcon is essentially a dp->hdmi dongle with dual personality.
>
> LS mode: It works as a passive dongle, by level shifting DP++
> signals to HDMI signals, in LS mode.
> PCON mode: It works as a protocol converter active dongle
> in pcon mode, by converting DP++ outputs to HDMI 2.0 outputs.
>
> This patch adds support for lspcon detection and mode set
> switch operations, as a dp dual mode dongle.
>
> v2: Addressed review comments from Ville
> - add adaptor id for lspcon devices (0x08), use it to identify lspcon
> - change function names
>   old: drm_lspcon_get_current_mode/drm_lspcon_change_mode
>   new: drm_lspcon_get_mode/drm_lspcon_set_mode
> - change drm_lspcon_get_mode type to int, to match
>   drm_dp_dual_mode_get_tmds_output
> - change 'err' to 'ret' to match the rest of the functions
> - remove pointless typecasting during call to dual_mode_read
> - fix the but while setting value of data, while writing lspcon mode
> - fix indentation
> - change mdelay(10) -> msleep(10)
> - return ETIMEDOUT instead of EFAULT, when lspcon mode change times out
> - Add an empty line to separate std regs macros and lspcon regs macros
>   Indent bit definition
>
> v3: Addressed review comments from Rodrigo
> - change macro name from DP_DUAL_MODE_TYPE_LSPCON to
>   DP_DUAL_MODE_TYPE_HAS_DPCD for better readability
> - change macro name from DP_DUAL_MODE_LSPCON_MODE_PCON to
>   DP_DUAL_MODE_LSPCON_MODE_PCON for better readability
> - add comment for MCA specific offsets like 0x40 and 0x41
> - remove DP_DUAL_MODE_REV_TYPE2 check while checking lspcon adapter id
>
> v4: Addressed review comments from Ville
> - Fixed indentation at few places
> - s/current_mode/mode
> - s/reqd_mode/mode
> - remove unnecessary void* cast
> - remove drm_edid.h from includes
> - Add a comment for _HAS_DPCD
> - Fix enum description, for lspcon_mode.
>
> v5: Rebase
> v6: Rebase
>
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Pushed to drm-intel-next-queued with Dave's IRC ack to merge via Intel
trees.

BR,
Jani.


> ---
>  drivers/gpu/drm/drm_dp_dual_mode_helper.c | 103 ++++++++++++++++++++++++++++++
>  include/drm/drm_dp_dual_mode_helper.h     |  26 ++++++++
>  2 files changed, 129 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
> index a7b2a75..a7aeb1e 100644
> --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c
> +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
> @@ -148,6 +148,14 @@ static bool is_type2_adaptor(uint8_t adaptor_id)
>  			      DP_DUAL_MODE_REV_TYPE2);
>  }
>  
> +bool is_lspcon_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN],
> +	const uint8_t adaptor_id)
> +{
> +	return is_hdmi_adaptor(hdmi_id) &&
> +		(adaptor_id == (DP_DUAL_MODE_TYPE_TYPE2 |
> +		 DP_DUAL_MODE_TYPE_HAS_DPCD));
> +}
> +
>  /**
>   * drm_dp_dual_mode_detect - Identify the DP dual mode adaptor
>   * @adapter: I2C adapter for the DDC bus
> @@ -203,6 +211,8 @@ enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter)
>  	ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_ADAPTOR_ID,
>  				    &adaptor_id, sizeof(adaptor_id));
>  	if (ret == 0) {
> +		if (is_lspcon_adaptor(hdmi_id, adaptor_id))
> +			return DRM_DP_DUAL_MODE_LSPCON;
>  		if (is_type2_adaptor(adaptor_id)) {
>  			if (is_hdmi_adaptor(hdmi_id))
>  				return DRM_DP_DUAL_MODE_TYPE2_HDMI;
> @@ -364,3 +374,96 @@ const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type)
>  	}
>  }
>  EXPORT_SYMBOL(drm_dp_get_dual_mode_type_name);
> +
> +/**
> + * drm_lspcon_get_mode: Get LSPCON's current mode of operation by
> + * by reading offset (0x80, 0x41)
> + * @i2c_adapter: I2C-over-aux adapter
> + * @current_mode: out vaiable, current lspcon mode of operation
> + *
> + * Returns:
> + * 0 on success, sets the current_mode value to appropriate mode
> + * -error on failure
> + */
> +int drm_lspcon_get_mode(struct i2c_adapter *adapter,
> +			enum drm_lspcon_mode *mode)
> +{
> +	u8 data;
> +	int ret = 0;
> +
> +	if (!mode) {
> +		DRM_ERROR("NULL input\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Read Status: i2c over aux */
> +	ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_LSPCON_CURRENT_MODE,
> +				    &data, sizeof(data));
> +	if (ret < 0) {
> +		DRM_ERROR("LSPCON read(0x80, 0x41) failed\n");
> +		return -EFAULT;
> +	}
> +
> +	if (data & DP_DUAL_MODE_LSPCON_MODE_PCON)
> +		*mode = DRM_LSPCON_MODE_PCON;
> +	else
> +		*mode = DRM_LSPCON_MODE_LS;
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_lspcon_get_mode);
> +
> +/**
> + * drm_lspcon_change_mode: Change LSPCON's mode of operation by
> + * by writing offset (0x80, 0x40)
> + * @i2c_adapter: I2C-over-aux adapter
> + * @reqd_mode: required mode of operation
> + *
> + * Returns:
> + * 0 on success, -error on failure/timeout
> + */
> +int drm_lspcon_set_mode(struct i2c_adapter *adapter,
> +			enum drm_lspcon_mode mode)
> +{
> +	u8 data = 0;
> +	int ret;
> +	int time_out = 200;
> +	enum drm_lspcon_mode current_mode;
> +
> +	if (mode == DRM_LSPCON_MODE_PCON)
> +		data = DP_DUAL_MODE_LSPCON_MODE_PCON;
> +
> +	/* Change mode */
> +	ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_LSPCON_MODE_CHANGE,
> +				     &data, sizeof(data));
> +	if (ret < 0) {
> +		DRM_ERROR("LSPCON mode change failed\n");
> +		return ret;
> +	}
> +
> +	/*
> +	 * 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.
> +	 */
> +	do {
> +		ret = drm_lspcon_get_mode(adapter, &current_mode);
> +		if (ret) {
> +			DRM_ERROR("can't confirm LSPCON mode change\n");
> +			return ret;
> +		} else {
> +			if (current_mode != mode) {
> +				msleep(10);
> +				time_out -= 10;
> +			} else {
> +				DRM_DEBUG_KMS("LSPCON mode changed to %s\n",
> +						mode == DRM_LSPCON_MODE_LS ?
> +						"LS" : "PCON");
> +				return 0;
> +			}
> +		}
> +	} while (time_out);
> +
> +	DRM_ERROR("LSPCON mode change timed out\n");
> +	return -ETIMEDOUT;
> +}
> +EXPORT_SYMBOL(drm_lspcon_set_mode);
> diff --git a/include/drm/drm_dp_dual_mode_helper.h b/include/drm/drm_dp_dual_mode_helper.h
> index e8a9dfd..5567770 100644
> --- a/include/drm/drm_dp_dual_mode_helper.h
> +++ b/include/drm/drm_dp_dual_mode_helper.h
> @@ -40,6 +40,8 @@
>  #define  DP_DUAL_MODE_REV_TYPE2 0x00
>  #define  DP_DUAL_MODE_TYPE_MASK 0xf0
>  #define  DP_DUAL_MODE_TYPE_TYPE2 0xa0
> +/* This field is marked reserved in dual mode spec, used in LSPCON */
> +#define  DP_DUAL_MODE_TYPE_HAS_DPCD 0x08
>  #define DP_DUAL_MODE_IEEE_OUI 0x11 /* 11-13*/
>  #define  DP_DUAL_IEEE_OUI_LEN 3
>  #define DP_DUAL_DEVICE_ID 0x14 /* 14-19 */
> @@ -55,6 +57,11 @@
>  #define  DP_DUAL_MODE_CEC_ENABLE 0x01
>  #define DP_DUAL_MODE_I2C_SPEED_CTRL 0x22
>  
> +/* LSPCON specific registers, defined by MCA */
> +#define DP_DUAL_MODE_LSPCON_MODE_CHANGE		0x40
> +#define DP_DUAL_MODE_LSPCON_CURRENT_MODE		0x41
> +#define  DP_DUAL_MODE_LSPCON_MODE_PCON			0x1
> +
>  struct i2c_adapter;
>  
>  ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter,
> @@ -63,6 +70,19 @@ ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter,
>  			       u8 offset, const void *buffer, size_t size);
>  
>  /**
> +* enum drm_lspcon_mode
> +* @lspcon_mode_ls: Level shifter mode of LSPCON
> +*	which drives DP++ to HDMI 1.4 conversion.
> +* @lspcon_mode_pcon: Protocol converter mode of LSPCON
> +*	which drives DP++ to HDMI 2.0 active conversion.
> +*/
> +enum drm_lspcon_mode {
> +	DRM_LSPCON_MODE_INVALID,
> +	DRM_LSPCON_MODE_LS,
> +	DRM_LSPCON_MODE_PCON,
> +};
> +
> +/**
>   * enum drm_dp_dual_mode_type - Type of the DP dual mode adaptor
>   * @DRM_DP_DUAL_MODE_NONE: No DP dual mode adaptor
>   * @DRM_DP_DUAL_MODE_UNKNOWN: Could be either none or type 1 DVI adaptor
> @@ -70,6 +90,7 @@ ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter,
>   * @DRM_DP_DUAL_MODE_TYPE1_HDMI: Type 1 HDMI adaptor
>   * @DRM_DP_DUAL_MODE_TYPE2_DVI: Type 2 DVI adaptor
>   * @DRM_DP_DUAL_MODE_TYPE2_HDMI: Type 2 HDMI adaptor
> + * @DRM_DP_DUAL_MODE_TYPE2_LSPCON: Level shifter /protocol converter
>   */
>  enum drm_dp_dual_mode_type {
>  	DRM_DP_DUAL_MODE_NONE,
> @@ -78,6 +99,7 @@ enum drm_dp_dual_mode_type {
>  	DRM_DP_DUAL_MODE_TYPE1_HDMI,
>  	DRM_DP_DUAL_MODE_TYPE2_DVI,
>  	DRM_DP_DUAL_MODE_TYPE2_HDMI,
> +	DRM_DP_DUAL_MODE_LSPCON,
>  };
>  
>  enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter);
> @@ -89,4 +111,8 @@ int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type,
>  				     struct i2c_adapter *adapter, bool enable);
>  const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type);
>  
> +int drm_lspcon_get_mode(struct i2c_adapter *adapter,
> +			enum drm_lspcon_mode *current_mode);
> +int drm_lspcon_set_mode(struct i2c_adapter *adapter,
> +			enum drm_lspcon_mode reqd_mode);
>  #endif

-- 
Jani Nikula, Intel Open Source Technology Center
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