On Thu, Apr 07, 2022 at 10:32:11PM +0300, Jani Nikula wrote:
On Thu, 07 Apr 2022, Imre Deak imre.deak@intel.com wrote:
The next patch needs a way to read a DPCD register without the preceding wake-up read in drm_dp_dpcd_read(). Export drm_dp_dpcd_access() to allow this.
I think I'd rather you added a special "probe" function for this specific purpose. I think drm_dp_dpcd_access() is a too generic low level function to export, and runs the risk of complicating any potential future refactoring of the DP AUX code.
Something like this:
ssize_t drm_dp_dpcd_probe(struct drm_dp_aux *aux, unsigned int offset);
And you could reuse that for the wakeup in drm_dp_dpcd_read() too.
Ok, makes sense, I'll change that.
BR, Jani.
Cc: dri-devel@lists.freedesktop.org Signed-off-by: Imre Deak imre.deak@intel.com
drivers/gpu/drm/dp/drm_dp.c | 19 +++++++++++++++++-- include/drm/dp/drm_dp_helper.h | 2 ++ 2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/dp/drm_dp.c b/drivers/gpu/drm/dp/drm_dp.c index 580016a1b9eb7..8b181314edcbe 100644 --- a/drivers/gpu/drm/dp/drm_dp.c +++ b/drivers/gpu/drm/dp/drm_dp.c @@ -470,8 +470,22 @@ drm_dp_dump_access(const struct drm_dp_aux *aux,
- Both native and I2C-over-AUX transactions are supported.
*/
-static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request,
unsigned int offset, void *buffer, size_t size)+/**
- drm_dp_dpcd_access() - read or write a series of bytes from/to the DPCD
- @aux: DisplayPort AUX channel (SST)
- @request: DP_AUX_NATIVE_READ or DP_AUX_NATIVE_WRITE
- @offset: address of the (first) register to read or write
- @buffer: buffer with the register values to write or the register values read
- @size: number of bytes in @buffer
- Returns the number of bytes transferred on success, or a negative error
- code on failure. This is a low-level function only for SST sinks and cases
- where calling drm_dp_dpcd_read()/write() is not possible (for instance due
- to the wake-up register read in drm_dp_dpcd_read()). For all other cases
- the latter functions should be used.
- */
+int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request,
unsigned int offset, void *buffer, size_t size){ struct drm_dp_aux_msg msg; unsigned int retry, native_reply; @@ -526,6 +540,7 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, mutex_unlock(&aux->hw_mutex); return ret; } +EXPORT_SYMBOL(drm_dp_dpcd_access);
/**
- drm_dp_dpcd_read() - read a series of bytes from the DPCD
diff --git a/include/drm/dp/drm_dp_helper.h b/include/drm/dp/drm_dp_helper.h index 1eccd97419436..7cf6e83434a8c 100644 --- a/include/drm/dp/drm_dp_helper.h +++ b/include/drm/dp/drm_dp_helper.h @@ -2053,6 +2053,8 @@ struct drm_dp_aux { bool is_remote; };
+int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request,
unsigned int offset, void *buffer, size_t size);ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset, void *buffer, size_t size); ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset,
-- Jani Nikula, Intel Open Source Graphics Center