[PATCH v6 2/5] drm: add constant N value in helper file

Tanmay Shah
2020-06-12T01:52:35Z

From: Chandan Uddaraju <chandanu@codeaurora.org>

The constant N value (0x8000) is used by i915 DP
driver. Define this value in dp helper header file
to use in multiple Display Port drivers. Change
i915 driver accordingly.

Change in v6: Change commit message

Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>
Signed-off-by: Vara Reddy <varar@codeaurora.org>
Signed-off-by: Tanmay Shah <tanmay@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>
---
drivers/gpu/drm/i915/display/intel_display.c | 2 +-
include/drm/drm_dp_helper.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 9ea1a397d1b5..4b2cfff5b761 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -8085,7 +8085,7 @@ static void compute_m_n(unsigned int m, unsigned int n,
* which the devices expect also in synchronous clock mode.
*/
if (constant_n)
- *ret_n = 0x8000;
+ *ret_n = DP_LINK_CONSTANT_N_VALUE;
else
*ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX);

diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 2035ac44afde..589132ab9ab6 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1134,6 +1134,7 @@
#define DP_MST_PHYSICAL_PORT_0 0
#define DP_MST_LOGICAL_PORT_0 8

+#define DP_LINK_CONSTANT_N_VALUE 0x8000
#define DP_LINK_STATUS_SIZE 6
bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
int lane_count);
--
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