[PATCH 1/5] drm/dp: Add drm_dp_psr_setup_time()

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Add a small helper to parse the PSR setup time from the DPCD PSR
capabilities and return the value in microseconds.

Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/drm_dp_helper.c | 28 ++++++++++++++++++++++++++++
 include/drm/drm_dp_helper.h     |  2 ++
 2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index eeaf5a7c3aa7..71309778f3d3 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -822,3 +822,31 @@ void drm_dp_aux_unregister(struct drm_dp_aux *aux)
 	i2c_del_adapter(&aux->ddc);
 }
 EXPORT_SYMBOL(drm_dp_aux_unregister);
+
+/**
+ * drm_dp_psr_setup_time() - PSR setup in time usec
+ * @psr_cap: PSR capabilities from DPCD
+ *
+ * Returns:
+ * PSR setup time for the panel in microseconds,  negative
+ * error code on failure.
+ */
+int drm_dp_psr_setup_time(const u8 psr_cap[EDP_PSR_RECEIVER_CAP_SIZE])
+{
+	static const u16 psr_setup_time_us[] = {
+		[DP_PSR_SETUP_TIME_330] = 330,
+		[DP_PSR_SETUP_TIME_275] = 275,
+		[DP_PSR_SETUP_TIME_165] = 165,
+		[DP_PSR_SETUP_TIME_110] = 110,
+		[DP_PSR_SETUP_TIME_55] = 55,
+		[DP_PSR_SETUP_TIME_0] = 0,
+	};
+	int i;
+
+	i = psr_cap[1] & DP_PSR_SETUP_TIME_MASK;
+	if (i >= ARRAY_SIZE(psr_setup_time_us))
+		return -EINVAL;
+
+	return psr_setup_time_us[i];
+}
+EXPORT_SYMBOL(drm_dp_psr_setup_time);
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 5a848e734422..6aa74f7d45b4 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -657,6 +657,8 @@ struct edp_vsc_psr {
 #define EDP_VSC_PSR_UPDATE_RFB		(1<<1)
 #define EDP_VSC_PSR_CRC_VALUES_VALID	(1<<2)
 
+int drm_dp_psr_setup_time(const u8 psr_cap[EDP_PSR_RECEIVER_CAP_SIZE]);
+
 static inline int
 drm_dp_max_link_rate(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 {
-- 
2.7.4