On 01/08/2014 05:51 PM, Mike Turquette wrote:

Quoting Stephen Boyd (2013-12-23 17:12:26)

quoted

Add support to the clock core so that drivers can pass in a
regmap. If no regmap is specified try to query the device that's
registering the clock for its regmap. This should allow drivers
to use the core regmap helpers. This is based on a similar design
in the regulator framework.

Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <redacted>
---
  drivers/clk/clk.c            | 8 ++++++++
  include/linux/clk-provider.h | 7 +++++++
  2 files changed, 15 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 9ad7b71..5e71f5c 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c

@@ -20,6 +20,7 @@
  #include <linux/device.h>
  #include <linux/init.h>
  #include <linux/sched.h>
+#include <linux/regmap.h>

  static DEFINE_SPINLOCK(enable_lock);
  static DEFINE_MUTEX(prepare_lock);

@@ -1834,6 +1835,13 @@ static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
         clk->num_parents = hw->init->num_parents;
         hw->clk = clk;

+       if (hw->init->regmap)
+               hw->regmap = hw->init->regmap;

Hi Stephen,

The whole series looks good to me except for the placement of the regmap
details inside struct clk_hw. That structure exists only to hide struct
clk from the hardware-specific clock structure and I'd not like to set
the precedent of shoving per-clock data into it.

As an alternative, how about finding a way to put these per-clock regmap
details into the hardware-specific clock structure? I understand that
you want to make these ops available to others, which is why they are in
the public struct clk_hw. I'm just wondering if that is the right way to
do it...

Patch #3 illustrates the sort of struct-member-creep that worries me.
What is to stop someone from putting "unsigned int divider_reg" or
"unsigned int mux_reg", and then the thing just keeps growing.

I agree with Mike here. This definitely encourages struct field creep if 
more people want to use it.

I talked to Stephen is person and my recommendation is to not have any 
new fields other than struct regmap in clk_hw and remove the above 2 
lines of code.

quoted

+       else if (dev && dev_get_regmap(dev, NULL))
+               hw->regmap = dev_get_regmap(dev, NULL);

Move "struct regmap *regmap" into struct clk_hw (since it's truly 
reusable across clock types and is technically purely HW related) and 
update it from the device's regmap like above.

We can then provide __clk_regmap_enable(regmap, offset, enable_mask) 
helper functions. Then clock specific functions can use the helper. We 
can even a simple macro to generate these wrappers.

#define DEFINE_REGMAP_EN_DIS(clktype) \

int clk_type##_enable(clktype *c, ....) { }
int clk_type##_disable(clktype *c, ....) { }


That to me seems like a reasonable compromise.

Thanks,
Saravana
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