[PATCH] i2c: busses: bcm2835: convert from round_rate() to determine_rate()

[PATCH] i2c: busses: bcm2835: convert from round_rate() to determine_rate()

[Brian Masney]

The round_rate() clk ops is deprecated, so migrate this driver from
round_rate() to determine_rate() using the Coccinelle semantic patch
appended to the "under-the-cut" portion of the patch.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
Coccinelle semantic patch is below. It's large and I don't want to
pollute the kernel changelog with the same code hundreds of times,
so that's why it's included under the cut. For subsystems with more
than one patch, I've included it on the cover letter.

    virtual patch

    // Look up the current name of the round_rate function
    @ has_round_rate @
    identifier round_rate_name =~ ".*_round_rate";
    identifier hw_param, rate_param, parent_rate_param;
    @@

    long round_rate_name(struct clk_hw *hw_param, unsigned long rate_param,
                  unsigned long *parent_rate_param)
    {
    	...
    }

    // Rename the route_rate function name to determine_rate()
    @ script:python generate_name depends on has_round_rate @
    round_rate_name << has_round_rate.round_rate_name;
    new_name;
    @@

    coccinelle.new_name = round_rate_name.replace("_round_rate", "_determine_rate")

    // Change rate to req->rate; also change occurrences of 'return XXX'.
    @ chg_rate depends on generate_name @
    identifier has_round_rate.round_rate_name;
    identifier has_round_rate.hw_param;
    identifier has_round_rate.rate_param;
    identifier has_round_rate.parent_rate_param;
    identifier ERR =~ "E.*";
    expression E;
    @@

    long round_rate_name(struct clk_hw *hw_param, unsigned long rate_param,
                  unsigned long *parent_rate_param)
    {
    <...
    (
    -return -ERR;
    +return -ERR;
    |
    - return rate_param;
    + return 0;
    |
    - return E;
    + req->rate = E;
    +
    + return 0;
    |
    - rate_param
    + req->rate
    )
    ...>
    }

    // Coccinelle only transforms the first occurrence of the rate parameter
    // Run a second time. FIXME: Is there a better way to do this?
    @ chg_rate2 depends on generate_name @
    identifier has_round_rate.round_rate_name;
    identifier has_round_rate.hw_param;
    identifier has_round_rate.rate_param;
    identifier has_round_rate.parent_rate_param;
    @@

    long round_rate_name(struct clk_hw *hw_param, unsigned long rate_param,
                  unsigned long *parent_rate_param)
    {
    <...
    - rate_param
    + req->rate
    ...>
    }

    // Change parent_rate to req->best_parent_rate
    @ chg_parent_rate depends on generate_name @
    identifier has_round_rate.round_rate_name;
    identifier has_round_rate.hw_param;
    identifier has_round_rate.rate_param;
    identifier has_round_rate.parent_rate_param;
    @@

    long round_rate_name(struct clk_hw *hw_param, unsigned long rate_param,
                  unsigned long *parent_rate_param)
    {
    <...
    (
    - *parent_rate_param
    + req->best_parent_rate
    |
    - parent_rate_param
    + &req->best_parent_rate
    )
    ...>
    }

    // Convert the function definition from round_rate() to determine_rate()
    @ func_definition depends on chg_rate @
    identifier has_round_rate.round_rate_name;
    identifier has_round_rate.hw_param;
    identifier has_round_rate.rate_param;
    identifier has_round_rate.parent_rate_param;
    identifier generate_name.new_name;
    @@

    - long round_rate_name(struct clk_hw *hw_param, unsigned long rate_param,
    -               unsigned long *parent_rate_param)
    + int new_name(struct clk_hw *hw, struct clk_rate_request *req)
    {
        ...
    }

    // Update the ops from round_rate() to determine_rate()
    @ ops depends on func_definition @
    identifier has_round_rate.round_rate_name;
    identifier generate_name.new_name;
    @@

    {
        ...,
    -   .round_rate = round_rate_name,
    +   .determine_rate = new_name,
        ...,
    }

Note that I used coccinelle 1.2 instead of 1.3 since the newer version
adds unnecessary braces as described in this post.
https://lore.kernel.org/cocci/67642477-5f3e-4b2a-914d-579a54f48cbd@intel.com/
---
 drivers/i2c/busses/i2c-bcm2835.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index 8554e790f8e36c5a1cf56c0aab8556b377f2bbdf..0d7e2654a534e92a529f27fdc049812359678522 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -137,12 +137,14 @@ static int clk_bcm2835_i2c_set_rate(struct clk_hw *hw, unsigned long rate,
 	return 0;
 }
 
-static long clk_bcm2835_i2c_round_rate(struct clk_hw *hw, unsigned long rate,
-				unsigned long *parent_rate)
+static int clk_bcm2835_i2c_determine_rate(struct clk_hw *hw,
+					  struct clk_rate_request *req)
 {
-	u32 divider = clk_bcm2835_i2c_calc_divider(rate, *parent_rate);
+	u32 divider = clk_bcm2835_i2c_calc_divider(req->rate, req->best_parent_rate);
 
-	return DIV_ROUND_UP(*parent_rate, divider);
+	req->rate = DIV_ROUND_UP(req->best_parent_rate, divider);
+
+	return 0;
 }
 
 static unsigned long clk_bcm2835_i2c_recalc_rate(struct clk_hw *hw,
@@ -156,7 +158,7 @@ static unsigned long clk_bcm2835_i2c_recalc_rate(struct clk_hw *hw,
 
 static const struct clk_ops clk_bcm2835_i2c_ops = {
 	.set_rate = clk_bcm2835_i2c_set_rate,
-	.round_rate = clk_bcm2835_i2c_round_rate,
+	.determine_rate = clk_bcm2835_i2c_determine_rate,
 	.recalc_rate = clk_bcm2835_i2c_recalc_rate,
 };
 

---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20250729-i2c-round-rate-137335af1fad

Best regards,
-- 
Brian Masney <bmasney@redhat.com>

Re: [PATCH] i2c: busses: bcm2835: convert from round_rate() to determine_rate()

[Brian Masney]

Hi all,

On Sun, Aug 10, 2025 at 06:32:18PM -0400, Brian Masney wrote:
> The round_rate() clk ops is deprecated, so migrate this driver from
> round_rate() to determine_rate() using the Coccinelle semantic patch
> appended to the "under-the-cut" portion of the patch.
> 
> Signed-off-by: Brian Masney <bmasney@redhat.com>

Would it be possible to get this picked up for v6.18? I'd like to remove
this API from drivers/clk in v6.19.

Thanks,

Brian