clk: tegra: Add missing reset deassertion

commit 23a43cc437e747473d5f8f98b4fe189fb5c433b7 upstream.

Commit 4782c0a5dd88 ("clk: tegra: Don't deassert reset on enabling
clocks") removed deassertion of reset lines when enabling peripheral
clocks. This breaks the initialization of the DFLL driver which relied
on this behaviour.

Fix this problem by adding explicit deassert/assert requests to the
driver. Tested on Google Pixel C.

Cc: stable@vger.kernel.org
Fixes: 4782c0a5dd88 ("clk: tegra: Don't deassert reset on enabling clocks")
Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c
index 6144447..62238dc 100644 (file)
--- a/drivers/clk/tegra/clk-dfll.c
+++ b/drivers/clk/tegra/clk-dfll.c
@@ -271,6 +271,7 @@ struct tegra_dfll {
        struct clk                      *ref_clk;
        struct clk                      *i2c_clk;
        struct clk                      *dfll_clk;
+       struct reset_control            *dfll_rst;
        struct reset_control            *dvco_rst;
        unsigned long                   ref_rate;
        unsigned long                   i2c_clk_rate;
@@ -1464,6 +1465,7 @@ static int dfll_init(struct tegra_dfll *td)
                return -EINVAL;
        }
 
+       reset_control_deassert(td->dfll_rst);
        reset_control_deassert(td->dvco_rst);
 
        ret = clk_prepare(td->ref_clk);
@@ -1509,6 +1511,7 @@ di_err1:
        clk_unprepare(td->ref_clk);
 
        reset_control_assert(td->dvco_rst);
+       reset_control_assert(td->dfll_rst);
 
        return ret;
 }
@@ -1530,6 +1533,7 @@ int tegra_dfll_suspend(struct device *dev)
        }
 
        reset_control_assert(td->dvco_rst);
+       reset_control_assert(td->dfll_rst);
 
        return 0;
 }
@@ -1548,6 +1552,7 @@ int tegra_dfll_resume(struct device *dev)
 {
        struct tegra_dfll *td = dev_get_drvdata(dev);
 
+       reset_control_deassert(td->dfll_rst);
        reset_control_deassert(td->dvco_rst);
 
        pm_runtime_get_sync(td->dev);
@@ -1951,6 +1956,12 @@ int tegra_dfll_register(struct platform_device *pdev,
 
        td->soc = soc;
 
+       td->dfll_rst = devm_reset_control_get_optional(td->dev, "dfll");
+       if (IS_ERR(td->dfll_rst)) {
+               dev_err(td->dev, "couldn't get dfll reset\n");
+               return PTR_ERR(td->dfll_rst);
+       }
+
        td->dvco_rst = devm_reset_control_get(td->dev, "dvco");
        if (IS_ERR(td->dvco_rst)) {
                dev_err(td->dev, "couldn't get dvco reset\n");
@@ -2087,6 +2098,7 @@ struct tegra_dfll_soc_data *tegra_dfll_unregister(struct platform_device *pdev)
        clk_unprepare(td->i2c_clk);
 
        reset_control_assert(td->dvco_rst);
+       reset_control_assert(td->dfll_rst);
 
        return td->soc;
 }