Messages in this thread | | | Date | Mon, 13 Jan 2014 19:54:42 -0800 | From | Saravana Kannan <> | Subject | Re: [PATCH v4 02/15] clk: Allow drivers to pass in a regmap |
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On 01/08/2014 05:51 PM, Mike Turquette wrote: > Quoting Stephen Boyd (2013-12-23 17:12:26) >> 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 <sboyd@codeaurora.org> >> --- >> 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.
>> + 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 -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation
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