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[82.65.169.74]) by smtp.gmail.com with ESMTPSA id m9sm20557689wrq.78.2021.05.18.00.44.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 May 2021 00:44:51 -0700 (PDT) References: <20210517203724.1006254-1-martin.blumenstingl@googlemail.com> <20210517203724.1006254-2-martin.blumenstingl@googlemail.com> User-agent: mu4e 1.4.15; emacs 27.1 From: Jerome Brunet To: Martin Blumenstingl , mturquette@baylibre.com, sboyd@kernel.org, narmstrong@baylibre.com, linux-clk@vger.kernel.org Cc: khilman@baylibre.com, linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH RFC v1 1/3] clk: divider: Add re-usable determine_rate implementations In-reply-to: <20210517203724.1006254-2-martin.blumenstingl@googlemail.com> Message-ID: <1jtun01o5p.fsf@starbuckisacylon.baylibre.com> Date: Tue, 18 May 2021 09:44:51 +0200 MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org On Mon 17 May 2021 at 22:37, Martin Blumenstingl wrote: > These are useful when running on 32-bit systems to increase the upper > supported frequency limit. clk_ops.round_rate returns a signed long > which limits the maximum rate on 32-bit systems to 2^31 (or approx. > 2.14GHz). clk_ops.determine_rate internally uses an unsigned long so > the maximum rate on 32-bit systems is 2^32 or approx. 4.29GHz. > > Signed-off-by: Martin Blumenstingl > --- > drivers/clk/clk-divider.c | 39 +++++++++++++++++++++++++++++++++++- > include/linux/clk-provider.h | 6 ++++++ > 2 files changed, 44 insertions(+), 1 deletion(-) > > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c > index 344997203f0e..24c94d2a3643 100644 > --- a/drivers/clk/clk-divider.c > +++ b/drivers/clk/clk-divider.c > @@ -377,7 +377,6 @@ long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent, > } > EXPORT_SYMBOL_GPL(divider_ro_round_rate_parent); > > - > static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate, > unsigned long *prate) > { > @@ -399,6 +398,44 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate, > divider->width, divider->flags); > } > > +int divider_determine_rate(struct clk_hw *hw, struct clk_rate_request *req, > + const struct clk_div_table *table, u8 width, > + unsigned long flags) > +{ > + int div; > + > + div = clk_divider_bestdiv(hw, req->best_parent_hw, req->rate, > + &req->best_parent_rate, table, width, flags); > + > + req->rate = DIV_ROUND_UP_ULL((u64)req->best_parent_rate, div); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(divider_determine_rate); > + > +int divider_ro_determine_rate(struct clk_hw *hw, struct clk_rate_request *req, > + const struct clk_div_table *table, u8 width, > + unsigned long flags, unsigned int val) > +{ > + int div; > + > + div = _get_div(table, val, flags, width); > + > + /* Even a read-only clock can propagate a rate change */ > + if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) { > + if (!req->best_parent_hw) > + return -EINVAL; > + > + req->best_parent_rate = clk_hw_round_rate(req->best_parent_hw, > + req->rate * div); > + } > + > + req->rate = DIV_ROUND_UP_ULL((u64)req->best_parent_rate, div); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(divider_ro_determine_rate); For a final version, could you factorize the code with the .round_rate() variant ? It would remove a bit of duplication. Maybe determine_rate() can also replace round_rate() in the generic divider ops ? > + > int divider_get_val(unsigned long rate, unsigned long parent_rate, > const struct clk_div_table *table, u8 width, > unsigned long flags) > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h > index 162a2e5546a3..d83b829305c0 100644 > --- a/include/linux/clk-provider.h > +++ b/include/linux/clk-provider.h > @@ -629,6 +629,12 @@ long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent, > unsigned long rate, unsigned long *prate, > const struct clk_div_table *table, u8 width, > unsigned long flags, unsigned int val); > +int divider_determine_rate(struct clk_hw *hw, struct clk_rate_request *req, > + const struct clk_div_table *table, u8 width, > + unsigned long flags); > +int divider_ro_determine_rate(struct clk_hw *hw, struct clk_rate_request *req, > + const struct clk_div_table *table, u8 width, > + unsigned long flags, unsigned int val); > int divider_get_val(unsigned long rate, unsigned long parent_rate, > const struct clk_div_table *table, u8 width, > unsigned long flags);