OMAP: DSS2: Add new FEAT definitions for features missing from OMAP2

OMAP2 doesn't have CPR, PRELOAD nor FIR_COEF_V registers. Add new
feature definitions for those, and check the feature before accessing
those registers.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index a9eebd8..ee2052f 100644 (file)
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -159,7 +159,8 @@ void dispc_save_context(void)
        SR(TIMING_V(OMAP_DSS_CHANNEL_LCD));
        SR(POL_FREQ(OMAP_DSS_CHANNEL_LCD));
        SR(DIVISORo(OMAP_DSS_CHANNEL_LCD));
-       SR(GLOBAL_ALPHA);
+       if (dss_has_feature(FEAT_GLOBAL_ALPHA))
+               SR(GLOBAL_ALPHA);
        SR(SIZE_MGR(OMAP_DSS_CHANNEL_DIGIT));
        SR(SIZE_MGR(OMAP_DSS_CHANNEL_LCD));
        if (dss_has_feature(FEAT_MGR_LCD2)) {
@@ -189,20 +190,25 @@ void dispc_save_context(void)
        SR(DATA_CYCLE2(OMAP_DSS_CHANNEL_LCD));
        SR(DATA_CYCLE3(OMAP_DSS_CHANNEL_LCD));
 
-       SR(CPR_COEF_R(OMAP_DSS_CHANNEL_LCD));
-       SR(CPR_COEF_G(OMAP_DSS_CHANNEL_LCD));
-       SR(CPR_COEF_B(OMAP_DSS_CHANNEL_LCD));
+       if (dss_has_feature(FEAT_CPR)) {
+               SR(CPR_COEF_R(OMAP_DSS_CHANNEL_LCD));
+               SR(CPR_COEF_G(OMAP_DSS_CHANNEL_LCD));
+               SR(CPR_COEF_B(OMAP_DSS_CHANNEL_LCD));
+       }
        if (dss_has_feature(FEAT_MGR_LCD2)) {
-               SR(CPR_COEF_B(OMAP_DSS_CHANNEL_LCD2));
-               SR(CPR_COEF_G(OMAP_DSS_CHANNEL_LCD2));
-               SR(CPR_COEF_R(OMAP_DSS_CHANNEL_LCD2));
+               if (dss_has_feature(FEAT_CPR)) {
+                       SR(CPR_COEF_B(OMAP_DSS_CHANNEL_LCD2));
+                       SR(CPR_COEF_G(OMAP_DSS_CHANNEL_LCD2));
+                       SR(CPR_COEF_R(OMAP_DSS_CHANNEL_LCD2));
+               }
 
                SR(DATA_CYCLE1(OMAP_DSS_CHANNEL_LCD2));
                SR(DATA_CYCLE2(OMAP_DSS_CHANNEL_LCD2));
                SR(DATA_CYCLE3(OMAP_DSS_CHANNEL_LCD2));
        }
 
-       SR(OVL_PRELOAD(OMAP_DSS_GFX));
+       if (dss_has_feature(FEAT_PRELOAD))
+               SR(OVL_PRELOAD(OMAP_DSS_GFX));
 
        /* VID1 */
        SR(OVL_BA0(OMAP_DSS_VIDEO1));
@@ -227,8 +233,10 @@ void dispc_save_context(void)
        for (i = 0; i < 5; i++)
                SR(OVL_CONV_COEF(OMAP_DSS_VIDEO1, i));
 
-       for (i = 0; i < 8; i++)
-               SR(OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, i));
+       if (dss_has_feature(FEAT_FIR_COEF_V)) {
+               for (i = 0; i < 8; i++)
+                       SR(OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, i));
+       }
 
        if (dss_has_feature(FEAT_HANDLE_UV_SEPARATE)) {
                SR(OVL_BA0_UV(OMAP_DSS_VIDEO1));
@@ -249,7 +257,8 @@ void dispc_save_context(void)
        if (dss_has_feature(FEAT_ATTR2))
                SR(OVL_ATTRIBUTES2(OMAP_DSS_VIDEO1));
 
-       SR(OVL_PRELOAD(OMAP_DSS_VIDEO1));
+       if (dss_has_feature(FEAT_PRELOAD))
+               SR(OVL_PRELOAD(OMAP_DSS_VIDEO1));
 
        /* VID2 */
        SR(OVL_BA0(OMAP_DSS_VIDEO2));
@@ -274,8 +283,10 @@ void dispc_save_context(void)
        for (i = 0; i < 5; i++)
                SR(OVL_CONV_COEF(OMAP_DSS_VIDEO2, i));
 
-       for (i = 0; i < 8; i++)
-               SR(OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, i));
+       if (dss_has_feature(FEAT_FIR_COEF_V)) {
+               for (i = 0; i < 8; i++)
+                       SR(OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, i));
+       }
 
        if (dss_has_feature(FEAT_HANDLE_UV_SEPARATE)) {
                SR(OVL_BA0_UV(OMAP_DSS_VIDEO2));
@@ -296,7 +307,8 @@ void dispc_save_context(void)
        if (dss_has_feature(FEAT_ATTR2))
                SR(OVL_ATTRIBUTES2(OMAP_DSS_VIDEO2));
 
-       SR(OVL_PRELOAD(OMAP_DSS_VIDEO2));
+       if (dss_has_feature(FEAT_PRELOAD))
+               SR(OVL_PRELOAD(OMAP_DSS_VIDEO2));
 
        if (dss_has_feature(FEAT_CORE_CLK_DIV))
                SR(DIVISOR);
@@ -318,7 +330,8 @@ void dispc_restore_context(void)
        RR(TIMING_V(OMAP_DSS_CHANNEL_LCD));
        RR(POL_FREQ(OMAP_DSS_CHANNEL_LCD));
        RR(DIVISORo(OMAP_DSS_CHANNEL_LCD));
-       RR(GLOBAL_ALPHA);
+       if (dss_has_feature(FEAT_GLOBAL_ALPHA))
+               RR(GLOBAL_ALPHA);
        RR(SIZE_MGR(OMAP_DSS_CHANNEL_DIGIT));
        RR(SIZE_MGR(OMAP_DSS_CHANNEL_LCD));
        if (dss_has_feature(FEAT_MGR_LCD2)) {
@@ -348,20 +361,25 @@ void dispc_restore_context(void)
        RR(DATA_CYCLE2(OMAP_DSS_CHANNEL_LCD));
        RR(DATA_CYCLE3(OMAP_DSS_CHANNEL_LCD));
 
-       RR(CPR_COEF_R(OMAP_DSS_CHANNEL_LCD));
-       RR(CPR_COEF_G(OMAP_DSS_CHANNEL_LCD));
-       RR(CPR_COEF_B(OMAP_DSS_CHANNEL_LCD));
+       if (dss_has_feature(FEAT_CPR)) {
+               RR(CPR_COEF_R(OMAP_DSS_CHANNEL_LCD));
+               RR(CPR_COEF_G(OMAP_DSS_CHANNEL_LCD));
+               RR(CPR_COEF_B(OMAP_DSS_CHANNEL_LCD));
+       }
        if (dss_has_feature(FEAT_MGR_LCD2)) {
                RR(DATA_CYCLE1(OMAP_DSS_CHANNEL_LCD2));
                RR(DATA_CYCLE2(OMAP_DSS_CHANNEL_LCD2));
                RR(DATA_CYCLE3(OMAP_DSS_CHANNEL_LCD2));
 
-               RR(CPR_COEF_B(OMAP_DSS_CHANNEL_LCD2));
-               RR(CPR_COEF_G(OMAP_DSS_CHANNEL_LCD2));
-               RR(CPR_COEF_R(OMAP_DSS_CHANNEL_LCD2));
+               if (dss_has_feature(FEAT_CPR)) {
+                       RR(CPR_COEF_B(OMAP_DSS_CHANNEL_LCD2));
+                       RR(CPR_COEF_G(OMAP_DSS_CHANNEL_LCD2));
+                       RR(CPR_COEF_R(OMAP_DSS_CHANNEL_LCD2));
+               }
        }
 
-       RR(OVL_PRELOAD(OMAP_DSS_GFX));
+       if (dss_has_feature(FEAT_PRELOAD))
+               RR(OVL_PRELOAD(OMAP_DSS_GFX));
 
        /* VID1 */
        RR(OVL_BA0(OMAP_DSS_VIDEO1));
@@ -386,8 +404,10 @@ void dispc_restore_context(void)
        for (i = 0; i < 5; i++)
                RR(OVL_CONV_COEF(OMAP_DSS_VIDEO1, i));
 
-       for (i = 0; i < 8; i++)
-               RR(OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, i));
+       if (dss_has_feature(FEAT_FIR_COEF_V)) {
+               for (i = 0; i < 8; i++)
+                       RR(OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, i));
+       }
 
        if (dss_has_feature(FEAT_HANDLE_UV_SEPARATE)) {
                RR(OVL_BA0_UV(OMAP_DSS_VIDEO1));
@@ -408,7 +428,8 @@ void dispc_restore_context(void)
        if (dss_has_feature(FEAT_ATTR2))
                RR(OVL_ATTRIBUTES2(OMAP_DSS_VIDEO1));
 
-       RR(OVL_PRELOAD(OMAP_DSS_VIDEO1));
+       if (dss_has_feature(FEAT_PRELOAD))
+               RR(OVL_PRELOAD(OMAP_DSS_VIDEO1));
 
        /* VID2 */
        RR(OVL_BA0(OMAP_DSS_VIDEO2));
@@ -433,8 +454,10 @@ void dispc_restore_context(void)
        for (i = 0; i < 5; i++)
                RR(OVL_CONV_COEF(OMAP_DSS_VIDEO2, i));
 
-       for (i = 0; i < 8; i++)
-               RR(OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, i));
+       if (dss_has_feature(FEAT_FIR_COEF_V)) {
+               for (i = 0; i < 8; i++)
+                       RR(OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, i));
+       }
 
        if (dss_has_feature(FEAT_HANDLE_UV_SEPARATE)) {
                RR(OVL_BA0_UV(OMAP_DSS_VIDEO2));
@@ -455,7 +478,8 @@ void dispc_restore_context(void)
        if (dss_has_feature(FEAT_ATTR2))
                RR(OVL_ATTRIBUTES2(OMAP_DSS_VIDEO2));
 
-       RR(OVL_PRELOAD(OMAP_DSS_VIDEO2));
+       if (dss_has_feature(FEAT_PRELOAD))
+               RR(OVL_PRELOAD(OMAP_DSS_VIDEO2));
 
        if (dss_has_feature(FEAT_CORE_CLK_DIV))
                RR(DIVISOR);
@@ -2650,7 +2674,8 @@ void dispc_dump_regs(struct seq_file *s)
        DUMPREG(DISPC_TIMING_V(OMAP_DSS_CHANNEL_LCD));
        DUMPREG(DISPC_POL_FREQ(OMAP_DSS_CHANNEL_LCD));
        DUMPREG(DISPC_DIVISORo(OMAP_DSS_CHANNEL_LCD));
-       DUMPREG(DISPC_GLOBAL_ALPHA);
+       if (dss_has_feature(FEAT_GLOBAL_ALPHA))
+               DUMPREG(DISPC_GLOBAL_ALPHA);
        DUMPREG(DISPC_SIZE_MGR(OMAP_DSS_CHANNEL_DIGIT));
        DUMPREG(DISPC_SIZE_MGR(OMAP_DSS_CHANNEL_LCD));
        if (dss_has_feature(FEAT_MGR_LCD2)) {
@@ -2681,20 +2706,25 @@ void dispc_dump_regs(struct seq_file *s)
        DUMPREG(DISPC_DATA_CYCLE2(OMAP_DSS_CHANNEL_LCD));
        DUMPREG(DISPC_DATA_CYCLE3(OMAP_DSS_CHANNEL_LCD));
 
-       DUMPREG(DISPC_CPR_COEF_R(OMAP_DSS_CHANNEL_LCD));
-       DUMPREG(DISPC_CPR_COEF_G(OMAP_DSS_CHANNEL_LCD));
-       DUMPREG(DISPC_CPR_COEF_B(OMAP_DSS_CHANNEL_LCD));
+       if (dss_has_feature(FEAT_CPR)) {
+               DUMPREG(DISPC_CPR_COEF_R(OMAP_DSS_CHANNEL_LCD));
+               DUMPREG(DISPC_CPR_COEF_G(OMAP_DSS_CHANNEL_LCD));
+               DUMPREG(DISPC_CPR_COEF_B(OMAP_DSS_CHANNEL_LCD));
+       }
        if (dss_has_feature(FEAT_MGR_LCD2)) {
                DUMPREG(DISPC_DATA_CYCLE1(OMAP_DSS_CHANNEL_LCD2));
                DUMPREG(DISPC_DATA_CYCLE2(OMAP_DSS_CHANNEL_LCD2));
                DUMPREG(DISPC_DATA_CYCLE3(OMAP_DSS_CHANNEL_LCD2));
 
-               DUMPREG(DISPC_CPR_COEF_R(OMAP_DSS_CHANNEL_LCD2));
-               DUMPREG(DISPC_CPR_COEF_G(OMAP_DSS_CHANNEL_LCD2));
-               DUMPREG(DISPC_CPR_COEF_B(OMAP_DSS_CHANNEL_LCD2));
+               if (dss_has_feature(FEAT_CPR)) {
+                       DUMPREG(DISPC_CPR_COEF_R(OMAP_DSS_CHANNEL_LCD2));
+                       DUMPREG(DISPC_CPR_COEF_G(OMAP_DSS_CHANNEL_LCD2));
+                       DUMPREG(DISPC_CPR_COEF_B(OMAP_DSS_CHANNEL_LCD2));
+               }
        }
 
-       DUMPREG(DISPC_OVL_PRELOAD(OMAP_DSS_GFX));
+       if (dss_has_feature(FEAT_PRELOAD))
+               DUMPREG(DISPC_OVL_PRELOAD(OMAP_DSS_GFX));
 
        DUMPREG(DISPC_OVL_BA0(OMAP_DSS_VIDEO1));
        DUMPREG(DISPC_OVL_BA1(OMAP_DSS_VIDEO1));
@@ -2745,14 +2775,16 @@ void dispc_dump_regs(struct seq_file *s)
        DUMPREG(DISPC_OVL_CONV_COEF(OMAP_DSS_VIDEO1, 2));
        DUMPREG(DISPC_OVL_CONV_COEF(OMAP_DSS_VIDEO1, 3));
        DUMPREG(DISPC_OVL_CONV_COEF(OMAP_DSS_VIDEO1, 4));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 0));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 1));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 2));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 3));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 4));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 5));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 6));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 7));
+       if (dss_has_feature(FEAT_FIR_COEF_V)) {
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 0));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 1));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 2));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 3));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 4));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 5));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 6));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO1, 7));
+       }
 
        if (dss_has_feature(FEAT_HANDLE_UV_SEPARATE)) {
                DUMPREG(DISPC_OVL_BA0_UV(OMAP_DSS_VIDEO1));
@@ -2813,14 +2845,17 @@ void dispc_dump_regs(struct seq_file *s)
        DUMPREG(DISPC_OVL_CONV_COEF(OMAP_DSS_VIDEO2, 2));
        DUMPREG(DISPC_OVL_CONV_COEF(OMAP_DSS_VIDEO2, 3));
        DUMPREG(DISPC_OVL_CONV_COEF(OMAP_DSS_VIDEO2, 4));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 0));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 1));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 2));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 3));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 4));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 5));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 6));
-       DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 7));
+
+       if (dss_has_feature(FEAT_FIR_COEF_V)) {
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 0));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 1));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 2));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 3));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 4));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 5));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 6));
+               DUMPREG(DISPC_OVL_FIR_COEF_V(OMAP_DSS_VIDEO2, 7));
+       }
 
        if (dss_has_feature(FEAT_HANDLE_UV_SEPARATE)) {
                DUMPREG(DISPC_OVL_BA0_UV(OMAP_DSS_VIDEO2));
@@ -2859,8 +2894,10 @@ void dispc_dump_regs(struct seq_file *s)
        if (dss_has_feature(FEAT_ATTR2))
                DUMPREG(DISPC_OVL_ATTRIBUTES2(OMAP_DSS_VIDEO2));
 
-       DUMPREG(DISPC_OVL_PRELOAD(OMAP_DSS_VIDEO1));
-       DUMPREG(DISPC_OVL_PRELOAD(OMAP_DSS_VIDEO2));
+       if (dss_has_feature(FEAT_PRELOAD)) {
+               DUMPREG(DISPC_OVL_PRELOAD(OMAP_DSS_VIDEO1));
+               DUMPREG(DISPC_OVL_PRELOAD(OMAP_DSS_VIDEO2));
+       }
 
        dss_clk_disable(DSS_CLK_ICK | DSS_CLK_FCK);
 #undef DUMPREG

diff --git a/drivers/video/omap2/dss/dss_features.c b/drivers/video/omap2/dss/dss_features.c
index a588380..bd420f9 100644 (file)
--- a/drivers/video/omap2/dss/dss_features.c
+++ b/drivers/video/omap2/dss/dss_features.c
@@ -287,7 +287,8 @@ static const struct omap_dss_features omap3430_dss_features = {
                FEAT_FUNCGATED | FEAT_ROWREPEATENABLE |
                FEAT_LINEBUFFERSPLIT | FEAT_RESIZECONF |
                FEAT_DSI_PLL_FREQSEL | FEAT_DSI_REVERSE_TXCLKESC |
-               FEAT_VENC_REQUIRES_TV_DAC_CLK,
+               FEAT_VENC_REQUIRES_TV_DAC_CLK | FEAT_CPR | FEAT_PRELOAD |
+               FEAT_FIR_COEF_V,
 
        .num_mgrs = 2,
        .num_ovls = 3,
@@ -307,7 +308,8 @@ static const struct omap_dss_features omap3630_dss_features = {
                FEAT_PRE_MULT_ALPHA | FEAT_FUNCGATED |
                FEAT_ROWREPEATENABLE | FEAT_LINEBUFFERSPLIT |
                FEAT_RESIZECONF | FEAT_DSI_PLL_PWR_BUG |
-               FEAT_DSI_PLL_FREQSEL,
+               FEAT_DSI_PLL_FREQSEL | FEAT_CPR | FEAT_PRELOAD |
+               FEAT_FIR_COEF_V,
 
        .num_mgrs = 2,
        .num_ovls = 3,
@@ -328,7 +330,8 @@ static const struct omap_dss_features omap4430_es1_0_dss_features  = {
                FEAT_MGR_LCD2 | FEAT_GLOBAL_ALPHA_VID1 |
                FEAT_CORE_CLK_DIV | FEAT_LCD_CLK_SRC |
                FEAT_DSI_DCS_CMD_CONFIG_VC | FEAT_DSI_VC_OCP_WIDTH |
-               FEAT_DSI_GNQ | FEAT_HANDLE_UV_SEPARATE | FEAT_ATTR2,
+               FEAT_DSI_GNQ | FEAT_HANDLE_UV_SEPARATE | FEAT_ATTR2 |
+               FEAT_CPR | FEAT_PRELOAD | FEAT_FIR_COEF_V,
 
        .num_mgrs = 3,
        .num_ovls = 3,
@@ -349,7 +352,8 @@ static const struct omap_dss_features omap4_dss_features = {
                FEAT_CORE_CLK_DIV | FEAT_LCD_CLK_SRC |
                FEAT_DSI_DCS_CMD_CONFIG_VC | FEAT_DSI_VC_OCP_WIDTH |
                FEAT_DSI_GNQ | FEAT_HDMI_CTS_SWMODE |
-               FEAT_HANDLE_UV_SEPARATE | FEAT_ATTR2,
+               FEAT_HANDLE_UV_SEPARATE | FEAT_ATTR2 | FEAT_CPR |
+               FEAT_PRELOAD | FEAT_FIR_COEF_V,
 
        .num_mgrs = 3,
        .num_ovls = 3,

diff --git a/drivers/video/omap2/dss/dss_features.h b/drivers/video/omap2/dss/dss_features.h
index 3058e24..5be8103 100644 (file)
--- a/drivers/video/omap2/dss/dss_features.h
+++ b/drivers/video/omap2/dss/dss_features.h
@@ -52,6 +52,9 @@ enum dss_feat_id {
        FEAT_HANDLE_UV_SEPARATE         = 1 << 20,
        FEAT_ATTR2                      = 1 << 21,
        FEAT_VENC_REQUIRES_TV_DAC_CLK   = 1 << 22,
+       FEAT_CPR                        = 1 << 23,
+       FEAT_PRELOAD                    = 1 << 24,
+       FEAT_FIR_COEF_V                 = 1 << 25,
 };
 
 /* DSS register field id */

diff --git a/drivers/video/omap2/dss/overlay.c b/drivers/video/omap2/dss/overlay.c
index 0f08025..cfbfc57 100644 (file)
--- a/drivers/video/omap2/dss/overlay.c
+++ b/drivers/video/omap2/dss/overlay.c
@@ -238,6 +238,9 @@ static ssize_t overlay_global_alpha_store(struct omap_overlay *ovl,
        u8 alpha;
        struct omap_overlay_info info;
 
+       if (!dss_has_feature(FEAT_GLOBAL_ALPHA))
+               return -ENODEV;
+
        r = kstrtou8(buf, 0, &alpha);
        if (r)
                return r;