From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH] clk: Add support for setting clk_rate via debugfs
Date: Mon, 17 Jun 2019 14:05:02 +0200 [thread overview]
Message-ID: <20190617120502.10153-1-geert+renesas@glider.be> (raw)
For testing, it is useful to be able to specify a clock rate manually.
As this is a dangerous feature, it is not enabled by default.
Users need to modify the source directly and #define
CLOCK_ALLOW_WRITE_DEBUGFS.
This follows the spirit of commit 09c6ecd394105c48 ("regmap: Add support
for writing to regmap registers via debugfs").
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
drivers/clk/clk.c | 38 +++++++++++++++++++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index c68bc5f695912bf5..0529ac624ed73ba0 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2953,6 +2953,41 @@ static int clk_dump_show(struct seq_file *s, void *data)
}
DEFINE_SHOW_ATTRIBUTE(clk_dump);
+#undef CLOCK_ALLOW_WRITE_DEBUGFS
+#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
+/*
+ * This can be dangerous, therefore don't provide any real compile time
+ * configuration option for this feature.
+ * People who want to use this will need to modify the source code directly.
+ */
+static int clk_rate_set(void *data, u64 val)
+{
+ struct clk_core *core = data;
+ int ret;
+
+ clk_prepare_lock();
+ ret = clk_core_set_rate_nolock(core, val);
+ clk_prepare_unlock();
+
+ return ret;
+}
+
+#define clk_rate_mode 0644
+#else
+#define clk_rate_set NULL
+#define clk_rate_mode 0444
+#endif
+
+static int clk_rate_get(void *data, u64 *val)
+{
+ struct clk_core *core = data;
+
+ *val = core->rate;
+ return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(clk_rate_fops, clk_rate_get, clk_rate_set, "%llu\n");
+
static const struct {
unsigned long flag;
const char *name;
@@ -3029,7 +3064,8 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
root = debugfs_create_dir(core->name, pdentry);
core->dentry = root;
- debugfs_create_ulong("clk_rate", 0444, root, &core->rate);
+ debugfs_create_file("clk_rate", clk_rate_mode, root, core,
+ &clk_rate_fops);
debugfs_create_ulong("clk_accuracy", 0444, root, &core->accuracy);
debugfs_create_u32("clk_phase", 0444, root, &core->phase);
debugfs_create_file("clk_flags", 0444, root, core, &clk_flags_fops);
--
2.17.1
reply other threads:[~2019-06-17 12:05 UTC|newest]
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