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author | Shashank Sharma <shashank.sharma@intel.com> | 2017-03-13 16:54:02 +0530 |
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committer | Jani Nikula <jani.nikula@intel.com> | 2017-03-21 10:15:56 +0200 |
commit | 62c58af32c935a98a1e8d8ceb39a3a47b36fbbcd (patch) | |
tree | ea1dca1ec86bdb3f213f69f9899dd05e51cd2762 /drivers/gpu/drm/drm_scdc_helper.c | |
parent | afa1c763653e0fd68f2d1e3dca869c9453d8ef06 (diff) | |
download | linux-62c58af32c935a98a1e8d8ceb39a3a47b36fbbcd.tar.bz2 |
drm/edid: detect SCDC support in HF-VSDB
This patch does following:
- Adds a new structure (drm_hdmi_info) in drm_display_info.
This structure will be used to save and indicate if sink
supports advanced HDMI 2.0 features
- Adds another structure drm_scdc within drm_hdmi_info, to
reflect scdc support and capabilities in connected HDMI 2.0 sink.
- Checks the HF-VSDB block for presence of SCDC, and marks it
in scdc structure
- If SCDC is present, checks if sink is capable of generating
SCDC read request, and marks it in scdc structure.
V2: Addressed review comments
Thierry:
- Fix typos in commit message and make abbreviation consistent
across the commit message.
- Change structure object name from hdmi_info -> hdmi
- Fix typos and abbreviations in description of structure drm_hdmi_info
end the description with a full stop.
- Create a structure drm_scdc, and keep all information related to SCDC
register set (supported, read request supported) etc in it.
Ville:
- Change rr -> read_request
- Call drm_detect_scrambling function drm_parse_hf_vsdb so that all
of HF-VSDB parsing can be kept in same function, in incremental
patches.
V3: Rebase.
V4: Rebase.
V5: Rebase.
V6: Addressed review comments from Ville
- Add clock rate calculations for 1/10 and 1/40 ratios
- Remove leftovers from old patchset
V7: Added R-B from Jose.
V8: Rebase.
V9: Rebase.
V10: Rebase.
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1489404244-16608-5-git-send-email-shashank.sharma@intel.com
Diffstat (limited to 'drivers/gpu/drm/drm_scdc_helper.c')
-rw-r--r-- | drivers/gpu/drm/drm_scdc_helper.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_scdc_helper.c b/drivers/gpu/drm/drm_scdc_helper.c index c2dd33f89c17..3cd96a95736d 100644 --- a/drivers/gpu/drm/drm_scdc_helper.c +++ b/drivers/gpu/drm/drm_scdc_helper.c @@ -22,8 +22,10 @@ */ #include <linux/slab.h> +#include <linux/delay.h> #include <drm/drm_scdc_helper.h> +#include <drm/drmP.h> /** * DOC: scdc helpers @@ -121,3 +123,122 @@ ssize_t drm_scdc_write(struct i2c_adapter *adapter, u8 offset, return 0; } EXPORT_SYMBOL(drm_scdc_write); + +/** + * drm_scdc_check_scrambling_status - what is status of scrambling? + * @adapter: I2C adapter for DDC channel + * + * Reads the scrambler status over SCDC, and checks the + * scrambling status. + * + * Returns: + * True if the scrambling is enabled, false otherwise. + */ + +bool drm_scdc_get_scrambling_status(struct i2c_adapter *adapter) +{ + u8 status; + int ret; + + ret = drm_scdc_readb(adapter, SCDC_SCRAMBLER_STATUS, &status); + if (ret < 0) { + DRM_ERROR("Failed to read scrambling status, error %d\n", ret); + return false; + } + + return status & SCDC_SCRAMBLING_STATUS; +} +EXPORT_SYMBOL(drm_scdc_get_scrambling_status); + +/** + * drm_scdc_set_scrambling - enable scrambling + * @adapter: I2C adapter for DDC channel + * @enable: bool to indicate if scrambling is to be enabled/disabled + * + * Writes the TMDS config register over SCDC channel, and: + * enables scrambling when enable = 1 + * disables scrambling when enable = 0 + * + * Returns: + * True if scrambling is set/reset successfully, false otherwise. + */ + +bool drm_scdc_set_scrambling(struct i2c_adapter *adapter, bool enable) +{ + u8 config; + int ret; + + ret = drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config); + if (ret < 0) { + DRM_ERROR("Failed to read tmds config, err=%d\n", ret); + return false; + } + + if (enable) + config |= SCDC_SCRAMBLING_ENABLE; + else + config &= ~SCDC_SCRAMBLING_ENABLE; + + ret = drm_scdc_writeb(adapter, SCDC_TMDS_CONFIG, config); + if (ret < 0) { + DRM_ERROR("Failed to enable scrambling, error %d\n", ret); + return false; + } + + return true; +} +EXPORT_SYMBOL(drm_scdc_set_scrambling); + +/** + * drm_scdc_set_high_tmds_clock_ratio - set TMDS clock ratio + * @adapter: I2C adapter for DDC channel + * @set: ret or reset the high clock ratio + * + * TMDS clock ratio calculations go like this: + * TMDS character = 10 bit TMDS encoded value + * TMDS character rate = The rate at which TMDS characters are transmitted(Mcsc) + * TMDS bit rate = 10x TMDS character rate + * As per the spec: + * TMDS clock rate for pixel clock < 340 MHz = 1x the character rate + * = 1/10 pixel clock rate + * TMDS clock rate for pixel clock > 340 MHz = 0.25x the character rate + * = 1/40 pixel clock rate + * + * Writes to the TMDS config register over SCDC channel, and: + * sets TMDS clock ratio to 1/40 when set = 1 + * sets TMDS clock ratio to 1/10 when set = 0 + * + * Returns: + * True if write is successful, false otherwise. + */ +bool drm_scdc_set_high_tmds_clock_ratio(struct i2c_adapter *adapter, bool set) +{ + u8 config; + int ret; + + ret = drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config); + if (ret < 0) { + DRM_ERROR("Failed to read tmds config, err=%d\n", ret); + return false; + } + + if (set) + config |= SCDC_TMDS_BIT_CLOCK_RATIO_BY_40; + else + config &= ~SCDC_TMDS_BIT_CLOCK_RATIO_BY_40; + + ret = drm_scdc_writeb(adapter, SCDC_TMDS_CONFIG, config); + if (ret < 0) { + DRM_ERROR("Failed to set TMDS clock ratio, error %d\n", ret); + return false; + } + + /* + * The spec says that a source should wait minimum 1ms and maximum + * 100ms after writing the TMDS config for clock ratio. Lets allow a + * wait of upto 2ms here. + */ + usleep_range(1000, 2000); + return true; +} +EXPORT_SYMBOL(drm_scdc_set_high_tmds_clock_ratio); |