[PATCH] hwmon: ltc4282: convert from round_rate() to determine_rate()

[Brian Masney <bmasney@redhat.com>]

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/hwmon/ltc4282.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/hwmon/ltc4282.c b/drivers/hwmon/ltc4282.c
index 424fa9e3a0993f74d7bd1b2e3c98acd954217a98..dbb30abcd343f3dac46bd87cc52638b75eb5b275 100644
--- a/drivers/hwmon/ltc4282.c
+++ b/drivers/hwmon/ltc4282.c
@@ -177,13 +177,15 @@ static const unsigned int ltc4282_out_rates[] = {
 	LTC4282_CLKOUT_CNV, LTC4282_CLKOUT_SYSTEM
 };
 
-static long ltc4282_round_rate(struct clk_hw *hw, unsigned long rate,
-			       unsigned long *parent_rate)
+static int ltc4282_determine_rate(struct clk_hw *hw,
+				  struct clk_rate_request *req)
 {
-	int idx = find_closest(rate, ltc4282_out_rates,
+	int idx = find_closest(req->rate, ltc4282_out_rates,
 			       ARRAY_SIZE(ltc4282_out_rates));
 
-	return ltc4282_out_rates[idx];
+	req->rate = ltc4282_out_rates[idx];
+
+	return 0;
 }
 
 static unsigned long ltc4282_recalc_rate(struct clk_hw *hw,
@@ -1124,7 +1126,7 @@ static ssize_t ltc4282_energy_show(struct device *dev,
 
 static const struct clk_ops ltc4282_ops = {
 	.recalc_rate = ltc4282_recalc_rate,
-	.round_rate = ltc4282_round_rate,
+	.determine_rate = ltc4282_determine_rate,
 	.set_rate = ltc4282_set_rate,
 	.disable = ltc4282_disable,
 };

---
base-commit: b551c4e2a98a177a06148cf16505643cd2108386
change-id: 20250710-hwmon-round-rate-1b21b2bf5a53

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