On Mon, Apr 04, 2016 at 05:31:44PM +0530, Shashank Sharma wrote:
> This patch adds support for LSPCON devices in dp++ adaptor
> helper layer. LSPCON is DP++ type-2 adaptor with some customized
> functionalities, to provide additional features in Intel Gen9 HW.
> 
> LSPCON needs I2C-over-aux support to read/write control and
> data registers. This patch adds following:
>   - Functions for I2C over aux read/write
>   - Function to read EDID using I2c-over-aux
>   - Function to identify LSPCON among type-2 DP adaptors
> 
> Signed-off-by: Shashank Sharma <[email protected]>
> ---
>  drivers/gpu/drm/drm_dp_dual_mode_helper.c | 100 
> ++++++++++++++++++++++++++++++
>  include/drm/drm_dp_dual_mode_helper.h     |  10 +++
>  2 files changed, 110 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c 
> b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
> index b72b7bb..ce8e11c 100644
> --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c
> +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
> @@ -132,6 +132,99 @@ ssize_t drm_dp_dual_mode_write(struct i2c_adapter 
> *adapter,
>  }
>  EXPORT_SYMBOL(drm_dp_dual_mode_write);
>  
> +int drm_dp_dual_mode_get_edid(void *data,
> +     u8 *buf, unsigned int block, size_t len)
> +{
> +     struct i2c_adapter *adapter = data;
> +     unsigned char start = block * EDID_LENGTH;
> +     unsigned char segment = block >> 1;
> +     unsigned char xfers = segment ? 3 : 2;
> +     int ret, retries = 5;
> +
> +     do {
> +             struct i2c_msg msgs[] = {
> +                     {
> +                             .addr   = DP_DUAL_MODE_DDC_SEGMENT_ADDR,
> +                             .flags  = 0,
> +                             .len    = 1,
> +                             .buf    = &segment,
> +                     }, {
> +                             .addr   = DDC_ADDR,
> +                             .flags  = 0,
> +                             .len    = 1,
> +                             .buf    = &start,
> +                     }, {
> +                             .addr   = DDC_ADDR,
> +                             .flags  = I2C_M_RD,
> +                             .len    = len,
> +                             .buf    = buf,
> +                     }
> +             };
> +
> +             ret = adapter->algo->master_xfer(adapter, &msgs[3 - xfers],
> +                                             xfers);
> +
> +             if (ret == -ENXIO) {
> +                     DRM_ERROR("Non-existent adapter %s\n",
> +                             adapter->name);
> +                     break;
> +             }
> +     } while (ret != xfers && --retries);
> +
> +     return ret == xfers ? 0 : -1;
> +}
> +EXPORT_SYMBOL(drm_dp_dual_mode_get_edid);

This sort of stuff shouldn't be needed. All that should be needed is
passing the right i2c adapter to drm_get_edid() and whatnot.

> +
> +/*
> +* drm_dp_dual_mode_ioa_xfer
> +* Few dp->hdmi type 2 adaptors allow i2c_over_aux read/write
> +* to the control and status registers. These functions help
> +* to read/write from those.
> +*/
> +static int drm_dp_dual_mode_ioa_xfer(struct i2c_adapter *adapter,
> +             u8 *buffer, u8 offset, u8 no_of_bytes, u8 rw_flag)
> +{
> +     int err = 0;
> +
> +     struct i2c_msg msgs[] = {
> +                     {
> +                             .addr   = DP_DUAL_MODE_SLAVE_ADDRESS,
> +                             .flags  = 0,
> +                             .len    = 1,
> +                             .buf    = &offset,
> +                     }, {
> +                             .addr   = DP_DUAL_MODE_SLAVE_ADDRESS,
> +                             .flags  = rw_flag,
> +                             .len    = no_of_bytes,
> +                             .buf    = buffer,
> +                     }
> +     };
> +
> +     /* I2C over AUX here */
> +     err = adapter->algo->master_xfer(adapter, msgs, 2);
> +     if (err < 0)
> +             DRM_ERROR("LSPCON: Failed I2C over Aux read(addr=0x%x)\n",
> +                             (unsigned int)offset);
> +
> +     return err;
> +}
> +
> +int drm_dp_dual_mode_ioa_read(struct i2c_adapter *adapter, u8 *buffer,
> +             u8 offset, u8 no_of_bytes)
> +{
> +     return drm_dp_dual_mode_ioa_xfer(adapter, buffer, offset,
> +             no_of_bytes, I2C_M_RD);
> +}
> +EXPORT_SYMBOL(drm_dp_dual_mode_ioa_read);
> +
> +int drm_dp_dual_mode_ioa_write(struct i2c_adapter *adapter, u8 *buffer,
> +             u8 offset, u8 no_of_bytes)
> +{
> +     return drm_dp_dual_mode_ioa_xfer(adapter, buffer, offset,
> +             no_of_bytes, 0);
> +}
> +EXPORT_SYMBOL(drm_dp_dual_mode_ioa_write);

Aren't these just dupes of the dual mode helper read/write functions?

> +
>  static bool is_hdmi_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN])
>  {
>       static const char dp_dual_mode_hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] =
> @@ -141,6 +234,11 @@ static bool is_hdmi_adaptor(const char 
> hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN])
>                     sizeof(dp_dual_mode_hdmi_id)) == 0;
>  }
>  
> +bool is_lspcon_adaptor(const uint8_t adaptor_id)
> +{
> +     return adaptor_id == 0xa8;
> +}
> +
>  /**
>   * drm_dp_dual_mode_detect - Identyfy the DP dual mode adaptor
>   * adapter: I2C adapter for the DDC bus
> @@ -197,6 +295,8 @@ enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct 
> i2c_adapter *adapter)
>                                   &adaptor_id, sizeof(adaptor_id));
>       if (ret || (adaptor_id != (DP_DUAL_MODE_TYPE_TYPE2 |
>                                  DP_DUAL_MODE_REV_TYPE2))) {
> +             if (is_lspcon_adaptor(adaptor_id))
> +                     return DRM_DP_DUAL_MODE_TYPE2_LSPCON;

We should reorganize this a bit I think. Probably should end up looking
somehting like:

bool is_type2_adaptor();
bool is_lspcon_adaptor();

if (ret == 0) {
        if (is_lspcon_adaptor())
                return TYPE2_LSPCON;
        else if (is_type2_adaptor() && is_hdmi_adaptor)
                return TYPE2_HDMI;
        else if (is_type2_adaptor())
                return TYPE2_DVI;
}

if (is_hdmi...)
        return TYPE1_HDMI;
else
        return TYPE1_DVI;


>               if (is_hdmi_adaptor(hdmi_id))
>                       return DRM_DP_DUAL_MODE_TYPE1_HDMI;
>               else
> diff --git a/include/drm/drm_dp_dual_mode_helper.h 
> b/include/drm/drm_dp_dual_mode_helper.h
> index 8f8a8dc..26e3dd8 100644
> --- a/include/drm/drm_dp_dual_mode_helper.h
> +++ b/include/drm/drm_dp_dual_mode_helper.h
> @@ -24,6 +24,7 @@
>  #define DRM_DP_DUAL_MODE_HELPER_H
>  
>  #include <linux/types.h>
> +#include <drm/drm_edid.h>
>  
>  /*
>   * Optional for type 1 DVI adaptors
> @@ -55,6 +56,7 @@
>  #define  DP_DUAL_MODE_CEC_ENABLE 0x01
>  #define DP_DUAL_MODE_I2C_SPEED_CTRL 0x22
>  #define DP_DUAL_MODE_LAST_RESERVED 0xff
> +#define DP_DUAL_MODE_DDC_SEGMENT_ADDR 0x30
>  
>  struct i2c_adapter;
>  
> @@ -69,6 +71,7 @@ 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_TYPE2_LSPCON,
>  };
>  
>  enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter 
> *adapter);
> @@ -81,4 +84,11 @@ drm_dp_dual_mode_set_tmds_output(struct i2c_adapter 
> *adapter, bool enable);
>  const char
>  *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type);
>  
> +int drm_dp_dual_mode_ioa_read(struct i2c_adapter *adapter, u8 *buffer,
> +             u8 offset, u8 no_of_bytes);
> +int drm_dp_dual_mode_ioa_write(struct i2c_adapter *adapter, u8 *buffer,
> +             u8 offset, u8 no_of_bytes);
> +int drm_dp_dual_mode_get_edid(void *data,
> +     u8 *buf, unsigned int block, size_t len);
> +
>  #endif
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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