radeon: expose backlight class device for legacy LVDS encoder

Allows e.g. power management daemons to control the backlight level. Inspired
by the corresponding code in radeonfb.

[mjg@redhat.com: updated to add backlight type and make the connector the parent device]
Signed-off-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Airlie <airlied@linux.ie>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Sedat Dilek <sedat.dilek@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 273 insertions, 6 deletions

diff --git a/drivers/gpu/drm/radeon/Kconfig b/drivers/gpu/drm/radeon/Kconfig
index 1c02d23f6fcc..9746fee59f56 100644
--- a/drivers/gpu/drm/radeon/Kconfig
+++ b/drivers/gpu/drm/radeon/Kconfig
@@ -1,6 +1,7 @@
 config DRM_RADEON_KMS
         bool "Enable modesetting on radeon by default - NEW DRIVER"
         depends on DRM_RADEON
+        select BACKLIGHT_CLASS_DEVICE
         help
           Choose this option if you want kernel modesetting enabled by default.
 
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index 3f3c9aac46cc..28c7961cd19b 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -40,6 +40,10 @@ radeon_atombios_connected_scratch_regs(struct drm_connector *connector,
                                        struct drm_encoder *encoder,
                                        bool connected);
 
+extern void
+radeon_legacy_backlight_init(struct radeon_encoder *radeon_encoder,
+                             struct drm_connector *drm_connector);
+
 void radeon_connector_hotplug(struct drm_connector *connector)
 {
         struct drm_device *dev = connector->dev;
@@ -1526,6 +1530,17 @@ radeon_add_legacy_connector(struct drm_device *dev,
                 connector->polled = DRM_CONNECTOR_POLL_HPD;
         connector->display_info.subpixel_order = subpixel_order;
         drm_sysfs_connector_add(connector);
+        if (connector_type == DRM_MODE_CONNECTOR_LVDS) {
+                struct drm_encoder *drm_encoder;
+
+                list_for_each_entry(drm_encoder, &dev->mode_config.encoder_list, head) {
+                        struct radeon_encoder *radeon_encoder;
+
+                        radeon_encoder = to_radeon_encoder(drm_encoder);
+                        if (radeon_encoder->encoder_id == ENCODER_OBJECT_ID_INTERNAL_LVDS)
+                                radeon_legacy_backlight_init(radeon_encoder, connector);
+                }
+        }
         return;
 
 failed:
diff --git a/drivers/gpu/drm/radeon/radeon_legacy_encoders.c b/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
index 59f834ba283d..5b54268ed6b2 100644
--- a/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
@@ -28,6 +28,10 @@
 #include "radeon_drm.h"
 #include "radeon.h"
 #include "atom.h"
+#include <linux/backlight.h>
+#ifdef CONFIG_PMAC_BACKLIGHT
+#include <asm/backlight.h>
+#endif
 
 static void radeon_legacy_encoder_disable(struct drm_encoder *encoder)
 {
@@ -39,7 +43,7 @@ static void radeon_legacy_encoder_disable(struct drm_encoder *encoder)
         radeon_encoder->active_device = 0;
 }
 
-static void radeon_legacy_lvds_dpms(struct drm_encoder *encoder, int mode)
+static void radeon_legacy_lvds_update(struct drm_encoder *encoder, int mode)
 {
         struct drm_device *dev = encoder->dev;
         struct radeon_device *rdev = dev->dev_private;
@@ -47,15 +51,23 @@ static void radeon_legacy_lvds_dpms(struct drm_encoder *encoder, int mode)
         uint32_t lvds_gen_cntl, lvds_pll_cntl, pixclks_cntl, disp_pwr_man;
         int panel_pwr_delay = 2000;
         bool is_mac = false;
+        uint8_t backlight_level;
         DRM_DEBUG_KMS("\n");
 
+        lvds_gen_cntl = RREG32(RADEON_LVDS_GEN_CNTL);
+        backlight_level = (lvds_gen_cntl >> RADEON_LVDS_BL_MOD_LEVEL_SHIFT) & 0xff;
+
         if (radeon_encoder->enc_priv) {
                 if (rdev->is_atom_bios) {
                         struct radeon_encoder_atom_dig *lvds = radeon_encoder->enc_priv;
                         panel_pwr_delay = lvds->panel_pwr_delay;
+                        if (lvds->bl_dev)
+                                backlight_level = lvds->backlight_level;
                 } else {
                         struct radeon_encoder_lvds *lvds = radeon_encoder->enc_priv;
                         panel_pwr_delay = lvds->panel_pwr_delay;
+                        if (lvds->bl_dev)
+                                backlight_level = lvds->backlight_level;
                 }
         }
 
@@ -82,11 +94,13 @@ static void radeon_legacy_lvds_dpms(struct drm_encoder *encoder, int mode)
                 lvds_pll_cntl &= ~RADEON_LVDS_PLL_RESET;
                 WREG32(RADEON_LVDS_PLL_CNTL, lvds_pll_cntl);
 
-                lvds_gen_cntl = RREG32(RADEON_LVDS_GEN_CNTL);
-                lvds_gen_cntl |= (RADEON_LVDS_ON | RADEON_LVDS_EN | RADEON_LVDS_DIGON | RADEON_LVDS_BLON);
+                lvds_gen_cntl &= ~(RADEON_LVDS_DISPLAY_DIS |
+                                   RADEON_LVDS_BL_MOD_LEVEL_MASK);
+                lvds_gen_cntl |= (RADEON_LVDS_ON | RADEON_LVDS_EN |
+                                  RADEON_LVDS_DIGON | RADEON_LVDS_BLON |
+                                  (backlight_level << RADEON_LVDS_BL_MOD_LEVEL_SHIFT));
                 if (is_mac)
                         lvds_gen_cntl |= RADEON_LVDS_BL_MOD_EN;
-                lvds_gen_cntl &= ~(RADEON_LVDS_DISPLAY_DIS);
                 udelay(panel_pwr_delay * 1000);
                 WREG32(RADEON_LVDS_GEN_CNTL, lvds_gen_cntl);
                 break;
@@ -95,7 +109,6 @@ static void radeon_legacy_lvds_dpms(struct drm_encoder *encoder, int mode)
         case DRM_MODE_DPMS_OFF:
                 pixclks_cntl = RREG32_PLL(RADEON_PIXCLKS_CNTL);
                 WREG32_PLL_P(RADEON_PIXCLKS_CNTL, 0, ~RADEON_PIXCLK_LVDS_ALWAYS_ONb);
-                lvds_gen_cntl = RREG32(RADEON_LVDS_GEN_CNTL);
                 lvds_gen_cntl |= RADEON_LVDS_DISPLAY_DIS;
                 if (is_mac) {
                         lvds_gen_cntl &= ~RADEON_LVDS_BL_MOD_EN;
@@ -119,6 +132,25 @@ static void radeon_legacy_lvds_dpms(struct drm_encoder *encoder, int mode)
 
 }
 
+static void radeon_legacy_lvds_dpms(struct drm_encoder *encoder, int mode)
+{
+        struct radeon_device *rdev = encoder->dev->dev_private;
+        struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
+        DRM_DEBUG("\n");
+
+        if (radeon_encoder->enc_priv) {
+                if (rdev->is_atom_bios) {
+                        struct radeon_encoder_atom_dig *lvds = radeon_encoder->enc_priv;
+                        lvds->dpms_mode = mode;
+                } else {
+                        struct radeon_encoder_lvds *lvds = radeon_encoder->enc_priv;
+                        lvds->dpms_mode = mode;
+                }
+        }
+
+        radeon_legacy_lvds_update(encoder, mode);
+}
+
 static void radeon_legacy_lvds_prepare(struct drm_encoder *encoder)
 {
         struct radeon_device *rdev = encoder->dev->dev_private;
@@ -237,9 +269,222 @@ static const struct drm_encoder_helper_funcs radeon_legacy_lvds_helper_funcs = {
         .disable = radeon_legacy_encoder_disable,
 };
 
+#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
+
+#define MAX_RADEON_LEVEL 0xFF
+
+struct radeon_backlight_privdata {
+        struct radeon_encoder *encoder;
+        uint8_t negative;
+};
+
+static uint8_t radeon_legacy_lvds_level(struct backlight_device *bd)
+{
+        struct radeon_backlight_privdata *pdata = bl_get_data(bd);
+        uint8_t level;
+
+        /* Convert brightness to hardware level */
+        if (bd->props.brightness < 0)
+                level = 0;
+        else if (bd->props.brightness > MAX_RADEON_LEVEL)
+                level = MAX_RADEON_LEVEL;
+        else
+                level = bd->props.brightness;
+
+        if (pdata->negative)
+                level = MAX_RADEON_LEVEL - level;
+
+        return level;
+}
+
+static int radeon_legacy_backlight_update_status(struct backlight_device *bd)
+{
+        struct radeon_backlight_privdata *pdata = bl_get_data(bd);
+        struct radeon_encoder *radeon_encoder = pdata->encoder;
+        struct drm_device *dev = radeon_encoder->base.dev;
+        struct radeon_device *rdev = dev->dev_private;
+        int dpms_mode = DRM_MODE_DPMS_ON;
+
+        if (radeon_encoder->enc_priv) {
+                if (rdev->is_atom_bios) {
+                        struct radeon_encoder_atom_dig *lvds = radeon_encoder->enc_priv;
+                        dpms_mode = lvds->dpms_mode;
+                        lvds->backlight_level = radeon_legacy_lvds_level(bd);
+                } else {
+                        struct radeon_encoder_lvds *lvds = radeon_encoder->enc_priv;
+                        dpms_mode = lvds->dpms_mode;
+                        lvds->backlight_level = radeon_legacy_lvds_level(bd);
+                }
+        }
+
+        if (bd->props.brightness > 0)
+                radeon_legacy_lvds_update(&radeon_encoder->base, dpms_mode);
+        else
+                radeon_legacy_lvds_update(&radeon_encoder->base, DRM_MODE_DPMS_OFF);
+
+        return 0;
+}
+
+static int radeon_legacy_backlight_get_brightness(struct backlight_device *bd)
+{
+        struct radeon_backlight_privdata *pdata = bl_get_data(bd);
+        struct radeon_encoder *radeon_encoder = pdata->encoder;
+        struct drm_device *dev = radeon_encoder->base.dev;
+        struct radeon_device *rdev = dev->dev_private;
+        uint8_t backlight_level;
+
+        backlight_level = (RREG32(RADEON_LVDS_GEN_CNTL) >>
+                           RADEON_LVDS_BL_MOD_LEVEL_SHIFT) & 0xff;
+
+        return pdata->negative ? MAX_RADEON_LEVEL - backlight_level : backlight_level;
+}
+
+static const struct backlight_ops radeon_backlight_ops = {
+        .get_brightness = radeon_legacy_backlight_get_brightness,
+        .update_status  = radeon_legacy_backlight_update_status,
+};
+
+void radeon_legacy_backlight_init(struct radeon_encoder *radeon_encoder,
+                                  struct drm_connector *drm_connector)
+{
+        struct drm_device *dev = radeon_encoder->base.dev;
+        struct radeon_device *rdev = dev->dev_private;
+        struct backlight_device *bd;
+        struct backlight_properties props;
+        struct radeon_backlight_privdata *pdata;
+        uint8_t backlight_level;
+
+        if (!radeon_encoder->enc_priv)
+                return;
+
+#ifdef CONFIG_PMAC_BACKLIGHT
+        if (!pmac_has_backlight_type("ati") &&
+            !pmac_has_backlight_type("mnca"))
+                return;
+#endif
+
+        pdata = kmalloc(sizeof(struct radeon_backlight_privdata), GFP_KERNEL);
+        if (!pdata) {
+                DRM_ERROR("Memory allocation failed\n");
+                goto error;
+        }
+
+        props.max_brightness = MAX_RADEON_LEVEL;
+        props.type = BACKLIGHT_RAW;
+        bd = backlight_device_register("radeon_bl", &drm_connector->kdev,
+                                       pdata, &radeon_backlight_ops, &props);
+        if (IS_ERR(bd)) {
+                DRM_ERROR("Backlight registration failed\n");
+                goto error;
+        }
+
+        pdata->encoder = radeon_encoder;
+
+        backlight_level = (RREG32(RADEON_LVDS_GEN_CNTL) >>
+                           RADEON_LVDS_BL_MOD_LEVEL_SHIFT) & 0xff;
+
+        /* First, try to detect backlight level sense based on the assumption
+         * that firmware set it up at full brightness
+         */
+        if (backlight_level == 0)
+                pdata->negative = true;
+        else if (backlight_level == 0xff)
+                pdata->negative = false;
+        else {
+                /* XXX hack... maybe some day we can figure out in what direction
+                 * backlight should work on a given panel?
+                 */
+                pdata->negative = (rdev->family != CHIP_RV200 &&
+                                   rdev->family != CHIP_RV250 &&
+                                   rdev->family != CHIP_RV280 &&
+                                   rdev->family != CHIP_RV350);
+
+#ifdef CONFIG_PMAC_BACKLIGHT
+                pdata->negative = (pdata->negative ||
+                                   of_machine_is_compatible("PowerBook4,3") ||
+                                   of_machine_is_compatible("PowerBook6,3") ||
+                                   of_machine_is_compatible("PowerBook6,5"));
+#endif
+        }
+
+        if (rdev->is_atom_bios) {
+                struct radeon_encoder_atom_dig *lvds = radeon_encoder->enc_priv;
+                lvds->bl_dev = bd;
+        } else {
+                struct radeon_encoder_lvds *lvds = radeon_encoder->enc_priv;
+                lvds->bl_dev = bd;
+        }
+
+        bd->props.brightness = radeon_legacy_backlight_get_brightness(bd);
+        bd->props.power = FB_BLANK_UNBLANK;
+        backlight_update_status(bd);
+
+        DRM_INFO("radeon legacy LVDS backlight initialized\n");
+
+        return;
+
+error:
+        kfree(pdata);
+        return;
+}
+
+static void radeon_legacy_backlight_exit(struct radeon_encoder *radeon_encoder)
+{
+        struct drm_device *dev = radeon_encoder->base.dev;
+        struct radeon_device *rdev = dev->dev_private;
+        struct backlight_device *bd = NULL;
+
+        if (!radeon_encoder->enc_priv)
+                return;
+
+        if (rdev->is_atom_bios) {
+                struct radeon_encoder_atom_dig *lvds = radeon_encoder->enc_priv;
+                bd = lvds->bl_dev;
+                lvds->bl_dev = NULL;
+        } else {
+                struct radeon_encoder_lvds *lvds = radeon_encoder->enc_priv;
+                bd = lvds->bl_dev;
+                lvds->bl_dev = NULL;
+        }
+
+        if (bd) {
+                struct radeon_legacy_backlight_privdata *pdata;
+
+                pdata = bl_get_data(bd);
+                backlight_device_unregister(bd);
+                kfree(pdata);
+
+                DRM_INFO("radeon legacy LVDS backlight unloaded\n");
+        }
+}
+
+#else /* !CONFIG_BACKLIGHT_CLASS_DEVICE */
+
+void radeon_legacy_backlight_init(struct radeon_encoder *encoder)
+{
+}
+
+static void radeon_legacy_backlight_exit(struct radeon_encoder *encoder)
+{
+}
+
+#endif
+
+
+static void radeon_lvds_enc_destroy(struct drm_encoder *encoder)
+{
+        struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
+
+        if (radeon_encoder->enc_priv) {
+                radeon_legacy_backlight_exit(radeon_encoder);
+                kfree(radeon_encoder->enc_priv);
+        }
+        drm_encoder_cleanup(encoder);
+        kfree(radeon_encoder);
+}
 
 static const struct drm_encoder_funcs radeon_legacy_lvds_enc_funcs = {
-        .destroy = radeon_enc_destroy,
+        .destroy = radeon_lvds_enc_destroy,
 };
 
 static void radeon_legacy_primary_dac_dpms(struct drm_encoder *encoder, int mode)
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 5067d18d0009..e4582814bb78 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -302,6 +302,9 @@ struct radeon_encoder_lvds {
         uint32_t lvds_gen_cntl;
         /* panel mode */
         struct drm_display_mode native_mode;
+        struct backlight_device *bl_dev;
+        int      dpms_mode;
+        uint8_t  backlight_level;
 };
 
 struct radeon_encoder_tv_dac {
@@ -355,6 +358,9 @@ struct radeon_encoder_atom_dig {
         uint32_t lcd_ss_id;
         /* panel mode */
         struct drm_display_mode native_mode;
+        struct backlight_device *bl_dev;
+        int dpms_mode;
+        uint8_t backlight_level;
 };
 
 struct radeon_encoder_atom_dac {