diff options
author | Thierry Reding <treding@nvidia.com> | 2014-01-09 17:08:36 +0100 |
---|---|---|
committer | Thierry Reding <treding@nvidia.com> | 2014-01-23 15:51:32 +0100 |
commit | 13411ddd319057ae334a4084ebcf2c741b317f34 (patch) | |
tree | 9915698fb7fe169acd53b9b7f75347524ed04a98 /drivers/gpu/drm/tegra | |
parent | 70bf6878a874523e4b62992d07b5739298f8c1eb (diff) | |
download | linux-13411ddd319057ae334a4084ebcf2c741b317f34.tar.bz2 |
drm/tegra: Obtain head number from DT
The head number of a given display controller is fixed in hardware and
required to program outputs appropriately. Relying on the driver probe
order to determine this number will not work, since that could yield a
situation where the second head was probed first and would be assigned
head number 0 instead of 1.
By explicitly specifying the head number in the device tree, it is no
longer necessary to rely on these assumptions. As a fallback, if the
property isn't available, derive the head number from the display
controller node's position in the device tree. That's somewhat more
reliable than the previous default but not a proper solution.
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'drivers/gpu/drm/tegra')
-rw-r--r-- | drivers/gpu/drm/tegra/dc.c | 41 |
1 files changed, 39 insertions, 2 deletions
diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c index 386f3b4b0094..9336006b475d 100644 --- a/drivers/gpu/drm/tegra/dc.c +++ b/drivers/gpu/drm/tegra/dc.c @@ -1100,8 +1100,6 @@ static int tegra_dc_init(struct host1x_client *client) struct tegra_dc *dc = host1x_client_to_dc(client); int err; - dc->pipe = tegra->drm->mode_config.num_crtc; - drm_crtc_init(tegra->drm, &dc->base, &tegra_crtc_funcs); drm_mode_crtc_set_gamma_size(&dc->base, 256); drm_crtc_helper_add(&dc->base, &tegra_crtc_helper_funcs); @@ -1187,6 +1185,41 @@ static const struct of_device_id tegra_dc_of_match[] = { } }; +static int tegra_dc_parse_dt(struct tegra_dc *dc) +{ + struct device_node *np; + u32 value = 0; + int err; + + err = of_property_read_u32(dc->dev->of_node, "nvidia,head", &value); + if (err < 0) { + dev_err(dc->dev, "missing \"nvidia,head\" property\n"); + + /* + * If the nvidia,head property isn't present, try to find the + * correct head number by looking up the position of this + * display controller's node within the device tree. Assuming + * that the nodes are ordered properly in the DTS file and + * that the translation into a flattened device tree blob + * preserves that ordering this will actually yield the right + * head number. + * + * If those assumptions don't hold, this will still work for + * cases where only a single display controller is used. + */ + for_each_matching_node(np, tegra_dc_of_match) { + if (np == dc->dev->of_node) + break; + + value++; + } + } + + dc->pipe = value; + + return 0; +} + static int tegra_dc_probe(struct platform_device *pdev) { const struct of_device_id *id; @@ -1207,6 +1240,10 @@ static int tegra_dc_probe(struct platform_device *pdev) dc->dev = &pdev->dev; dc->soc = id->data; + err = tegra_dc_parse_dt(dc); + if (err < 0) + return err; + dc->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(dc->clk)) { dev_err(&pdev->dev, "failed to get clock\n"); |