drm/i915: Use DIV_ROUND_CLOSEST for PWM calculations

vsyrjala · vsyrjala · commit 37f2248e3d42 · 2016-03-04T14:46:52.000+02:00
Supposedly we would want to get the PWM output as close as possible to the target, so let's round to closest. Cc: Jani Nikula <jani.nikula@linux.intel.com> Suggested-by: Jani Nikula <jani.nikula@linux.intel.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1456932138-14004-7-git-send-email-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
@@ -1240,7 +1240,7 @@ static void intel_backlight_device_unregister(struct intel_connector *connector)
  */
 static u32 bxt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 {
-	return KHz(19200) / pwm_freq_hz;
+	return DIV_ROUND_CLOSEST(KHz(19200), pwm_freq_hz);
 }
 
 /*
@@ -1258,7 +1258,7 @@ static u32 spt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 	else
 		mul = 16;
 
-	return MHz(24) / (pwm_freq_hz * mul);
+	return DIV_ROUND_CLOSEST(MHz(24), pwm_freq_hz * mul);
 }
 
 /*
@@ -1281,7 +1281,7 @@ static u32 lpt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 	else
 		clock = MHz(24); /* LPT:LP */
 
-	return clock / (pwm_freq_hz * mul);
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);
 }
 
 /*
@@ -1292,7 +1292,7 @@ static u32 pch_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
 
-	return KHz(dev_priv->rawclk_freq) / (pwm_freq_hz * 128);
+	return DIV_ROUND_CLOSEST(KHz(dev_priv->rawclk_freq), pwm_freq_hz * 128);
 }
 
 /*
@@ -1313,7 +1313,7 @@ static u32 i9xx_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 	else
 		clock = KHz(dev_priv->cdclk_freq);
 
-	return clock / (pwm_freq_hz * 32);
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 32);
 }
 
 /*
@@ -1332,7 +1332,7 @@ static u32 i965_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 	else
 		clock = KHz(dev_priv->cdclk_freq);
 
-	return clock / (pwm_freq_hz * 128);
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 128);
 }
 
 /*
@@ -1356,7 +1356,7 @@ static u32 vlv_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 		mul = 128;
 	}
 
-	return clock / (pwm_freq_hz * mul);
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);
 }
 
 static u32 get_backlight_max_vbt(struct intel_connector *connector)

Original file line number	Diff line number	Diff line change
`@@ -1240,7 +1240,7 @@ static void intel_backlight_device_unregister(struct intel_connector *connector)`
`1240`	`1240`	`*/`
`1241`	`1241`	`static u32 bxt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)`
`1242`	`1242`	`{`
`1243`		`- return KHz(19200) / pwm_freq_hz;`
	`1243`	`+ return DIV_ROUND_CLOSEST(KHz(19200), pwm_freq_hz);`
`1244`	`1244`	`}`
`1245`	`1245`
`1246`	`1246`	`/*`
`@@ -1258,7 +1258,7 @@ static u32 spt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)`
`1258`	`1258`	`else`
`1259`	`1259`	`mul = 16;`
`1260`	`1260`
`1261`		`- return MHz(24) / (pwm_freq_hz * mul);`
	`1261`	`+ return DIV_ROUND_CLOSEST(MHz(24), pwm_freq_hz * mul);`
`1262`	`1262`	`}`
`1263`	`1263`
`1264`	`1264`	`/*`
`@@ -1281,7 +1281,7 @@ static u32 lpt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)`
`1281`	`1281`	`else`
`1282`	`1282`	`clock = MHz(24); /* LPT:LP */`
`1283`	`1283`
`1284`		`- return clock / (pwm_freq_hz * mul);`
	`1284`	`+ return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);`
`1285`	`1285`	`}`
`1286`	`1286`
`1287`	`1287`	`/*`
`@@ -1292,7 +1292,7 @@ static u32 pch_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)`
`1292`	`1292`	`{`
`1293`	`1293`	`struct drm_i915_private *dev_priv = to_i915(connector->base.dev);`
`1294`	`1294`
`1295`		`- return KHz(dev_priv->rawclk_freq) / (pwm_freq_hz * 128);`
	`1295`	`+ return DIV_ROUND_CLOSEST(KHz(dev_priv->rawclk_freq), pwm_freq_hz * 128);`
`1296`	`1296`	`}`
`1297`	`1297`
`1298`	`1298`	`/*`
`@@ -1313,7 +1313,7 @@ static u32 i9xx_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)`
`1313`	`1313`	`else`
`1314`	`1314`	`clock = KHz(dev_priv->cdclk_freq);`
`1315`	`1315`
`1316`		`- return clock / (pwm_freq_hz * 32);`
	`1316`	`+ return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 32);`
`1317`	`1317`	`}`
`1318`	`1318`
`1319`	`1319`	`/*`
`@@ -1332,7 +1332,7 @@ static u32 i965_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)`
`1332`	`1332`	`else`
`1333`	`1333`	`clock = KHz(dev_priv->cdclk_freq);`
`1334`	`1334`
`1335`		`- return clock / (pwm_freq_hz * 128);`
	`1335`	`+ return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 128);`
`1336`	`1336`	`}`
`1337`	`1337`
`1338`	`1338`	`/*`
`@@ -1356,7 +1356,7 @@ static u32 vlv_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)`
`1356`	`1356`	`mul = 128;`
`1357`	`1357`	`}`
`1358`	`1358`
`1359`		`- return clock / (pwm_freq_hz * mul);`
	`1359`	`+ return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);`
`1360`	`1360`	`}`
`1361`	`1361`
`1362`	`1362`	`static u32 get_backlight_max_vbt(struct intel_connector *connector)`