[PATCH] clk: tegra: ensure all provided clock values are valid cookies

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

Tegra's clock implementation uses pointers as the clock cookies, and
hence chooses to make NULL an invalid clock cookie. However, there are
gaps in the assigned device tree clock IDs, and hence the array mapping
DT clock ID contains entries with NULL values (uninitialized BSS) unless
explicit action is taken. This patch enhances the Tegra clock code to
detect this case and explicitly initialize those lookup table entries to
an error value. This prevents clk_get() from ever returning NULL. Hence,
Tegra's clock APIs don't have to check the clock cookie they're passed
for NULL.

Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
Mike, this also will need to go through the Tegra tree; just looking for
any review/ack from you. Thanks.

 drivers/clk/tegra/clk-tegra20.c |    5 ++++-
 drivers/clk/tegra/clk-tegra30.c |    5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/tegra/clk-tegra20.c b/drivers/clk/tegra/clk-tegra20.c
index 5847b5e..e59ac14 100644
--- a/drivers/clk/tegra/clk-tegra20.c
+++ b/drivers/clk/tegra/clk-tegra20.c
@@ -1243,12 +1243,15 @@ void __init tegra20_clock_init(struct device_node *np)
 	tegra20_audio_clk_init();
 
 
-	for (i = 0; i < ARRAY_SIZE(clks); i++)
+	for (i = 0; i < ARRAY_SIZE(clks); i++) {
 		if (IS_ERR(clks[i])) {
 			pr_err("Tegra20 clk %d: register failed with %ld\n",
 			       i, PTR_ERR(clks[i]));
 			BUG();
 		}
+		if (!clks[i])
+			clks[i] = ERR_PTR(-EINVAL);
+	}
 
 	tegra_init_dup_clks(tegra_clk_duplicates, clks, clk_max);
 
diff --git a/drivers/clk/tegra/clk-tegra30.c b/drivers/clk/tegra/clk-tegra30.c
index 987312c..9c0b2ee 100644
--- a/drivers/clk/tegra/clk-tegra30.c
+++ b/drivers/clk/tegra/clk-tegra30.c
@@ -2022,12 +2022,15 @@ void __init tegra30_clock_init(struct device_node *np)
 	tegra30_audio_clk_init();
 	tegra30_pmc_clk_init();
 
-	for (i = 0; i < ARRAY_SIZE(clks); i++)
+	for (i = 0; i < ARRAY_SIZE(clks); i++) {
 		if (IS_ERR(clks[i])) {
 			pr_err("Tegra30 clk %d: register failed with %ld\n",
 			       i, PTR_ERR(clks[i]));
 			BUG();
 		}
+		if (!clks[i])
+			clks[i] = ERR_PTR(-EINVAL);
+	}
 
 	tegra_init_dup_clks(tegra_clk_duplicates, clks, clk_max);
 
-- 
1.7.10.4