On 2019-10-15 06:48, Biwen Li wrote:
> This adds property idle-state
>
> Signed-off-by: Biwen Li <biwen.li@xxxxxxx>
> ---
> Change in v2:
> - update subject and description
> - add property idle-state
>
> drivers/i2c/muxes/i2c-mux-pca954x.c | 47 ++++++++++++++++++-----------
> 1 file changed, 30 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
> index 923aa3a5a3dc..8ec586342b92 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)
> @@ -402,6 +402,25 @@ static void pca954x_cleanup(struct i2c_mux_core *muxc)
> i2c_mux_del_adapters(muxc);
> }
>
> +static int pca954x_init(struct i2c_client *client, struct pca954x *data)
> +{
> + /*
> + * Write the mux register at addr to verify
> + * that the mux is in fact present. This also
> + * initializes the mux to disconnected state.
> + */
This comment belongs in pca954x_probe, before the call to this function.
However, the comment may now be be wrong since the mux is not always
initialized to the disconnected state.
> + if (data->idle_state >= 0) {
> + /* Always enable multiplexer */
While I understand that it is important for your case that the mux is
always enabled, this is just a side effect of having a specific
idle-state. I suggest that you remove this comment.
> + if (data->chip->muxtype == pca954x_ismux)
> + data->last_chan = data->idle_state | data->chip->enable;
> + else
> + data->last_chan = 1 << data->idle_state;
The meat of this "if" is still duplicated, I was suggesting a helper
that only did the regval calculation so that the new helper could
also be used from pca954x_select_chan.
> + } else {
> + /* Disconnect multiplexer */
> + data->last_chan = 0; /* force the first selection */
These two comments should be combined.
> + }
> + return i2c_smbus_write_byte(client, data->last_chan);
> +}
> /*
> * I2C init/probing/exit functions
> */
> @@ -411,7 +430,6 @@ 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 +480,18 @@ static int pca954x_probe(struct i2c_client *client,
> }
> }
>
> - /* 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 (of_property_read_u32(np, "idle-state", &data->idle_state))
> + data->idle_state = MUX_IDLE_AS_IS;
> +
> + if (of_property_read_bool(np, "i2c-mux-idle-disconnect"))
> + data->idle_state = MUX_IDLE_DISCONNECT;
I think you should ignore i2c-mux-idle-disconnect if idle-state is present.
I.e. move this "if" statement into the body of the former "if". Also, you have
broken things if np is NULL.
Cheers,
Peter
> +
> + ret = pca954x_init(client, data);
> + 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;
>
> ret = pca954x_irq_setup(muxc);
> if (ret)
> @@ -531,8 +545,7 @@ 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);
> + return pca954x_init(client, data);
> }
> #endif
>
>
