On Mon, Dec 13, 2021 at 12:43:12PM +0100, Uwe Kleine-König wrote:
> Using counter->priv is a memory read and so more expensive than
> container_of which is only an addition. (In this case even a noop
> because the offset is 0.)
>
> So container_of is expected to be a tad faster, it's type-safe, and
> produces smaller code (ARCH=arm allmodconfig):
>
> $ source/scripts/bloat-o-meter drivers/counter/ti-eqep.o-pre drivers/counter/ti-eqep.o
> add/remove: 0/0 grow/shrink: 0/9 up/down: 0/-108 (-108)
> Function old new delta
> ti_eqep_position_enable_write 132 120 -12
> ti_eqep_position_enable_read 260 248 -12
> ti_eqep_position_ceiling_write 132 120 -12
> ti_eqep_position_ceiling_read 236 224 -12
> ti_eqep_function_write 220 208 -12
> ti_eqep_function_read 372 360 -12
> ti_eqep_count_write 312 300 -12
> ti_eqep_count_read 236 224 -12
> ti_eqep_action_read 664 652 -12
> Total: Before=4598, After=4490, chg -2.35%
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
I'll pick this up and submit it with the rest of the Counter changes for
this cycle.
Thanks,
William Breathitt Gray
> ---
> drivers/counter/ti-eqep.c | 23 ++++++++++++++---------
> 1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
> index 09817c953f9a..9e0e46bca4c2 100644
> --- a/drivers/counter/ti-eqep.c
> +++ b/drivers/counter/ti-eqep.c
> @@ -87,10 +87,15 @@ struct ti_eqep_cnt {
> struct regmap *regmap16;
> };
>
> +static struct ti_eqep_cnt *ti_eqep_count_from_counter(struct counter_device *counter)
> +{
> + return container_of(counter, struct ti_eqep_cnt, counter);
> +}
> +
> static int ti_eqep_count_read(struct counter_device *counter,
> struct counter_count *count, u64 *val)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
> u32 cnt;
>
> regmap_read(priv->regmap32, QPOSCNT, &cnt);
> @@ -102,7 +107,7 @@ static int ti_eqep_count_read(struct counter_device *counter,
> static int ti_eqep_count_write(struct counter_device *counter,
> struct counter_count *count, u64 val)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
> u32 max;
>
> regmap_read(priv->regmap32, QPOSMAX, &max);
> @@ -116,7 +121,7 @@ static int ti_eqep_function_read(struct counter_device *counter,
> struct counter_count *count,
> enum counter_function *function)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
> u32 qdecctl;
>
> regmap_read(priv->regmap16, QDECCTL, &qdecctl);
> @@ -143,7 +148,7 @@ static int ti_eqep_function_write(struct counter_device *counter,
> struct counter_count *count,
> enum counter_function function)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
> enum ti_eqep_count_func qsrc;
>
> switch (function) {
> @@ -173,7 +178,7 @@ static int ti_eqep_action_read(struct counter_device *counter,
> struct counter_synapse *synapse,
> enum counter_synapse_action *action)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
> enum counter_function function;
> u32 qdecctl;
> int err;
> @@ -245,7 +250,7 @@ static int ti_eqep_position_ceiling_read(struct counter_device *counter,
> struct counter_count *count,
> u64 *ceiling)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
> u32 qposmax;
>
> regmap_read(priv->regmap32, QPOSMAX, &qposmax);
> @@ -259,7 +264,7 @@ static int ti_eqep_position_ceiling_write(struct counter_device *counter,
> struct counter_count *count,
> u64 ceiling)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
>
> if (ceiling != (u32)ceiling)
> return -ERANGE;
> @@ -272,7 +277,7 @@ static int ti_eqep_position_ceiling_write(struct counter_device *counter,
> static int ti_eqep_position_enable_read(struct counter_device *counter,
> struct counter_count *count, u8 *enable)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
> u32 qepctl;
>
> regmap_read(priv->regmap16, QEPCTL, &qepctl);
> @@ -285,7 +290,7 @@ static int ti_eqep_position_enable_read(struct counter_device *counter,
> static int ti_eqep_position_enable_write(struct counter_device *counter,
> struct counter_count *count, u8 enable)
> {
> - struct ti_eqep_cnt *priv = counter->priv;
> + struct ti_eqep_cnt *priv = ti_eqep_count_from_counter(counter);
>
> regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, enable ? -1 : 0);
>
>
> base-commit: fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf
> --
> 2.30.2
>
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