Re: [PATCH] USB: typec: tps6598x: use device 'type' field to identify devices

[Alexandru Ardelean]

On Wed, Nov 29, 2023 at 4:26 PM Heikki Krogerus
<heikki.krogerus@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> Sorry to keep you waiting.

No worries.
I know how this works: maintainers do what they can, when they can.

>
> On Thu, Nov 23, 2023 at 11:00:21PM +0200, Alexandru Ardelean wrote:
> > Using the {of_}device_is_compatible function(s) is not too expensive.
> > But since the driver already needs to match for the 'struct tipd_data'
> > device parameters (via device_get_match_data()), we can add a simple 'type'
> > field.
> >
> > This adds a minor optimization in certain operations, where we the check
> > for TPS25750 (or Apple CD321X) is a bit faster.
> >
> > Signed-off-by: Alexandru Ardelean <alex@xxxxxxxxxxx>
> > ---
> >  drivers/usb/typec/tipd/core.c | 34 ++++++++++++++++++++++------------
> >  1 file changed, 22 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
> > index fbd23de5c5cb..69d3e11bb30c 100644
> > --- a/drivers/usb/typec/tipd/core.c
> > +++ b/drivers/usb/typec/tipd/core.c
> > @@ -105,7 +105,14 @@ static const char *const modes[] = {
> >
> >  struct tps6598x;
> >
> > +enum tipd_type {
> > +     TIPD_TYPE_TI_TPS6598X,
> > +     TIPD_TYPE_APPLE_CD321X,
> > +     TIPD_TYPE_TI_TPS25750X,
> > +};
> > +
> >  struct tipd_data {
> > +     enum tipd_type type;
> >       irq_handler_t irq_handler;
> >       int (*register_port)(struct tps6598x *tps, struct fwnode_handle *node);
> >       void (*trace_power_status)(u16 status);
>
> Why not just match against the structures themselves?
>
>         if (tps->data == &tps25750_data)

Sure.
This version also works.
I've been more accustomed to the enum version.
Will update.

As a broader context, this patch came along from trying to backport
some patches back to 5.15.
device_is_compatible() is not present i 5.15
of_device_is_compatible is present there.
It seemed like doing a neutral version (between 5.15 and latest
kernel) looks like a good idea.

>                 ...
>
> > @@ -1195,7 +1202,6 @@ tps25750_register_port(struct tps6598x *tps, struct fwnode_handle *fwnode)
> >
> >  static int tps6598x_probe(struct i2c_client *client)
> >  {
> > -     struct device_node *np = client->dev.of_node;
> >       struct tps6598x *tps;
> >       struct fwnode_handle *fwnode;
> >       u32 status;
> > @@ -1211,11 +1217,19 @@ static int tps6598x_probe(struct i2c_client *client)
> >       mutex_init(&tps->lock);
> >       tps->dev = &client->dev;
> >
> > +     if (dev_fwnode(tps->dev))
> > +             tps->data = device_get_match_data(tps->dev);
> > +     else
> > +             tps->data = i2c_get_match_data(client);
> > +
> > +     if (!tps->data)
> > +             return -EINVAL;
> > +
> >       tps->regmap = devm_regmap_init_i2c(client, &tps6598x_regmap_config);
> >       if (IS_ERR(tps->regmap))
> >               return PTR_ERR(tps->regmap);
> >
> > -     is_tps25750 = device_is_compatible(tps->dev, "ti,tps25750");
> > +     is_tps25750 = (tps->data->type == TIPD_TYPE_TI_TPS25750X);
> >       if (!is_tps25750) {
> >               ret = tps6598x_read32(tps, TPS_REG_VID, &vid);
> >               if (ret < 0 || !vid)
> > @@ -1229,7 +1243,7 @@ static int tps6598x_probe(struct i2c_client *client)
> >       if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> >               tps->i2c_protocol = true;
> >
> > -     if (np && of_device_is_compatible(np, "apple,cd321x")) {
> > +     if (tps->data->type == TIPD_TYPE_APPLE_CD321X) {
> >               /* Switch CD321X chips to the correct system power state */
> >               ret = cd321x_switch_power_state(tps, TPS_SYSTEM_POWER_STATE_S0);
> >               if (ret)
> > @@ -1247,13 +1261,6 @@ static int tps6598x_probe(struct i2c_client *client)
> >                       TPS_REG_INT_PLUG_EVENT;
> >       }
> >
> > -     if (dev_fwnode(tps->dev))
> > -             tps->data = device_get_match_data(tps->dev);
> > -     else
> > -             tps->data = i2c_get_match_data(client);
> > -     if (!tps->data)
> > -             return -EINVAL;
> > -
> >       /* Make sure the controller has application firmware running */
> >       ret = tps6598x_check_mode(tps);
> >       if (ret < 0)
> > @@ -1366,7 +1373,7 @@ static void tps6598x_remove(struct i2c_client *client)
> >       usb_role_switch_put(tps->role_sw);
> >
> >       /* Reset PD controller to remove any applied patch */
> > -     if (device_is_compatible(tps->dev, "ti,tps25750"))
> > +     if (tps->data->type == TIPD_TYPE_TI_TPS25750X)
> >               tps6598x_exec_cmd_tmo(tps, "GAID", 0, NULL, 0, NULL, 2000, 0);
> >  }
> >
> > @@ -1396,7 +1403,7 @@ static int __maybe_unused tps6598x_resume(struct device *dev)
> >       if (ret < 0)
> >               return ret;
> >
> > -     if (device_is_compatible(tps->dev, "ti,tps25750") && ret == TPS_MODE_PTCH) {
> > +     if (tps->data->type == TIPD_TYPE_TI_TPS25750X && ret == TPS_MODE_PTCH) {
> >               ret = tps25750_init(tps);
> >               if (ret)
> >                       return ret;
> > @@ -1419,6 +1426,7 @@ static const struct dev_pm_ops tps6598x_pm_ops = {
> >  };
> >
> >  static const struct tipd_data cd321x_data = {
> > +     .type = TIPD_TYPE_APPLE_CD321X,
> >       .irq_handler = cd321x_interrupt,
> >       .register_port = tps6598x_register_port,
> >       .trace_power_status = trace_tps6598x_power_status,
> > @@ -1426,6 +1434,7 @@ static const struct tipd_data cd321x_data = {
> >  };
> >
> >  static const struct tipd_data tps6598x_data = {
> > +     .type = TIPD_TYPE_TI_TPS6598X,
> >       .irq_handler = tps6598x_interrupt,
> >       .register_port = tps6598x_register_port,
> >       .trace_power_status = trace_tps6598x_power_status,
> > @@ -1433,6 +1442,7 @@ static const struct tipd_data tps6598x_data = {
> >  };
> >
> >  static const struct tipd_data tps25750_data = {
> > +     .type = TIPD_TYPE_TI_TPS25750X,
> >       .irq_handler = tps25750_interrupt,
> >       .register_port = tps25750_register_port,
> >       .trace_power_status = trace_tps25750_power_status,
> > --
> > 2.42.1
>
> thanks,
>
> --
> heikki