Re: [PATCH] clk: debugfs add clk_rate_fops with DEBUG

Quoting Zhangfei Gao (2013-08-18 22:34:17)

clk_rate_fops is added to debug

1. set_rate (e.g. PLL)
2. Choose mux parent, since mux could choose parent accordingly when set_rate.

Causion: set_rate can be called directly from user space

Example: sfc_mux have two parents: 24M and 200M

cat clk_summary clock enable_cnt prepare_cnt rate

---

osc24mhz 3 3 24000000 bpll_fout3 0 0 200000000 sfc_mux 0 0 200000000 sfc 0 0 200000000

cat osc24mhz/bpll/bpll_fout3/sfc_mux/sfc/clk_rate 200000000

echo 24000000 > osc24mhz/bpll/bpll_fout3/sfc_mux/sfc/clk_rate cat clk_summary clock enable_cnt prepare_cnt rate

---

osc24mhz 3 3 24000000 sfc_mux 0 0 24000000 sfc 0 0 24000000 bpll_fout3 0 0 200000000

cat osc24mhz/sfc_mux/sfc/clk_rate 24000000

Signed-off-by: Zhangfei Gao zhangfei.gao@linaro.org

Thanks for the patch. It is trivial enough where I think we can leave it on the list and let developers apply it if they need it for debug. I don't want to merge it since it exposes hardware control to userspace and could be abused in a way that could damage a device.

Regards, Mike

---

drivers/clk/clk.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 373cd54..6b582f7 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -226,6 +226,35 @@ static const struct file_operations clk_dump_fops = { .release = single_release, }; +#ifdef DEBUG +static int clk_rate_fops_get(void *data, u64 *rate) +{

•   struct clk *clk = data;
  

•   *rate = clk->rate;
  

•   return 0;
  

+};

+static int clk_rate_fops_set(void *data, u64 rate) +{

•   struct clk *clk = data;
  

•   int ret = 0;
  

•   ret = clk_prepare_enable(clk);
  

•   if (ret)
  

•           goto out;
  

•   clk_set_rate(clk, rate);
  

•   clk_disable_unprepare(clk);
  

+out:

•   return ret;
  

+};

+DEFINE_SIMPLE_ATTRIBUTE(clk_rate_fops, clk_rate_fops_get,

•                   clk_rate_fops_set, "%llu\n");
  

+#endif

/* caller must hold prepare_lock */ static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) { @@ -243,8 +272,13 @@ static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) clk->dentry = d; +#ifdef DEBUG

•   d = debugfs_create_file("clk_rate", S_IWUSR | S_IRUGO, clk->dentry,
  

•                           clk, &clk_rate_fops);
  

+#else d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry, (u32 *)&clk->rate); +#endif if (!d) goto err_out; -- 1.7.9.5