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Message-ID: <DB7PR04MB44906BE3732F777C4DBB67538F930@DB7PR04MB4490.eurprd04.prod.outlook.com>
Date: Tue, 15 Oct 2019 03:17:50 +0000
From: Biwen Li <biwen.li@....com>
To: Peter Rosin <peda@...ntia.se>, Leo Li <leoyang.li@....com>,
"robh+dt@...nel.org" <robh+dt@...nel.org>,
"mark.rutland@....com" <mark.rutland@....com>
CC: "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: RE: [EXT] Re: [PATCH 2/2] i2c: mux: pca954x: replace property
i2c-mux-idle-disconnect
>
> Caution: EXT Email
>
> On 2019-10-14 13:25, Biwen Li wrote:
> > This replaces property i2c-mux-idle-disconnect with idle-state
> >
> > Signed-off-by: Biwen Li <biwen.li@....com>
> > ---
> > drivers/i2c/muxes/i2c-mux-pca954x.c | 44
> > ++++++++++++++++++++---------
> > 1 file changed, 31 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c
> > b/drivers/i2c/muxes/i2c-mux-pca954x.c
> > index 923aa3a5a3dc..a330929c4d67 100644
> > --- a/drivers/i2c/muxes/i2c-mux-pca954x.c
> > +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
> > @@ -86,7 +86,7 @@ struct pca954x {
> >
> > u8 last_chan; /* last register value */
> > /* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */
> > - s8 idle_state;
> > + s32 idle_state;
> >
> > struct i2c_client *client;
> >
> > @@ -256,7 +256,7 @@ static int pca954x_deselect_mux(struct
> > i2c_mux_core *muxc, u32 chan) {
> > struct pca954x *data = i2c_mux_priv(muxc);
> > struct i2c_client *client = data->client;
> > - s8 idle_state;
> > + s32 idle_state;
> >
> > idle_state = READ_ONCE(data->idle_state);
> > if (idle_state >= 0)
> > @@ -411,7 +411,6 @@ static int pca954x_probe(struct i2c_client *client,
> > struct i2c_adapter *adap = client->adapter;
> > struct device *dev = &client->dev;
> > struct device_node *np = dev->of_node;
> > - bool idle_disconnect_dt;
> > struct gpio_desc *gpio;
> > struct i2c_mux_core *muxc;
> > struct pca954x *data;
> > @@ -462,22 +461,31 @@ static int pca954x_probe(struct i2c_client
> *client,
> > }
> > }
> >
> > + if (of_property_read_u32(np, "idle-state", &data->idle_state))
> > + data->idle_state = MUX_IDLE_AS_IS;
> > +
> > /* Write the mux register at addr to verify
> > * that the mux is in fact present. This also
> > * initializes the mux to disconnected state.
> > */
> > - if (i2c_smbus_write_byte(client, 0) < 0) {
> > + if (data->idle_state >= 0){
>
> Space before {
Okay, got it, I will add it in v2.
>
> > + data->last_chan = data->idle_state;
>
> data->last_chan should have the actual register value, i.e. (untested)
Okay, got it, I will adjust it in v2.
>
> if (data->chip->muxtype == pca954x_ismux)
> data->last_chan = data->idle_state |
> data->chip->enable;
> else
> data->last_chan = 1 << data->idle_state;
>
> ret = i2c_smbus_write_byte(client, data->last_chan);
>
> But since this regval calculation is now needed in three places, it should be
> moved to a helper function.
You are right, I will add a helper function in v2.
>
> > + /* Always enable multiplexer */
> > + ret = i2c_smbus_write_byte(client, data->last_chan |
> > + (data->chip->muxtype ==
> pca954x_ismux ?
> > + data->chip->enable : 0));
> > + }
> > + else{
>
> Space before {
Got it, I will add it in v2.
>
> Naturally, you have the exact same issues in the pca954x_resume hunk,
> below.
Got it
>
> > + data->last_chan = 0; /* force the first
> selection */
> > + /* Disconnect multiplexer */
> > + ret = i2c_smbus_write_byte(client, data->last_chan);
> > + }
> > +
> > + if (ret < 0) {
> > dev_warn(dev, "probe failed\n");
> > return -ENODEV;
> > }
> >
> > - data->last_chan = 0; /* force the first selection */
> > - data->idle_state = MUX_IDLE_AS_IS;
> > -
> > - idle_disconnect_dt = np &&
> > - of_property_read_bool(np, "i2c-mux-idle-disconnect");
> > - if (idle_disconnect_dt)
> > - data->idle_state = MUX_IDLE_DISCONNECT;
>
> In case the idle-state property is missing, you need to fall back to the old
> behavior and handle i2c-mux-idle-disconnect as before.
Okay, got it, I will add it in v2.
>
> Cheers,
> Peter
>
> >
> > ret = pca954x_irq_setup(muxc);
> > if (ret)
> > @@ -531,8 +539,18 @@ static int pca954x_resume(struct device *dev)
> > struct i2c_mux_core *muxc = i2c_get_clientdata(client);
> > struct pca954x *data = i2c_mux_priv(muxc);
> >
> > - data->last_chan = 0;
> > - return i2c_smbus_write_byte(client, 0);
> > + if (data->idle_state >= 0){
> > + data->last_chan = data->idle_state;
> > + /* Always enable multiplexer */
> > + return i2c_smbus_write_byte(client, data->last_chan |
> > + (data->chip->muxtype ==
> pca954x_ismux ?
> > + data->chip->enable : 0));
> > + }
> > + else{
> > + data->last_chan = 0;
> > + /* Disconnect multiplexer */
> > + return i2c_smbus_write_byte(client, data->last_chan);
> > + }
> > }
> > #endif
> >
> >
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