[PATCH v2] i2c: fsi: Create busses for all ports

[Eddie James]

On 6/6/19 6:52 AM, Oliver O'Halloran wrote:
> Currently we only create an I2C bus for the ports listed in the
> device-tree for that master. There's no real reason for this since
> we can discover the number of ports the master supports by looking
> at the port_max field of the status register.
>
> This patch re-works the bus add logic so that we always create buses
> for each port, unless the bus is marked as unavailable in the DT. This
> is useful since it ensures that all the buses provided by the CFAM I2C
> master are accessible to debug tools.


Thanks Oliver.

Reviewed-by: Eddie James <eajames at linux.ibm.com>


>
> Cc: Eddie James <eajames at linux.vnet.ibm.com>
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
> v2: Fixed off-by-one when calulating the number of ports.
>      Compile fixes.
> ---
>   drivers/i2c/busses/i2c-fsi.c | 32 +++++++++++++++++++++++++++-----
>   1 file changed, 27 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c
> index 1e2be2219a60..da5eb3960def 100644
> --- a/drivers/i2c/busses/i2c-fsi.c
> +++ b/drivers/i2c/busses/i2c-fsi.c
> @@ -658,13 +658,29 @@ static const struct i2c_algorithm fsi_i2c_algorithm = {
>   	.functionality = fsi_i2c_functionality,
>   };
>   
> +static struct device_node *fsi_i2c_find_port_of_node(struct device_node *fsi,
> +						     int port)
> +{
> +	struct device_node *np;
> +	u32 port_no;
> +	int rc;
> +
> +	for_each_child_of_node(fsi, np) {
> +		rc = of_property_read_u32(np, "reg", &port_no);
> +		if (!rc && port_no == port)
> +			return np;
> +	}
> +
> +	return NULL;
> +}
> +
>   static int fsi_i2c_probe(struct device *dev)
>   {
>   	struct fsi_i2c_master *i2c;
>   	struct fsi_i2c_port *port;
>   	struct device_node *np;
> +	u32 port_no, ports, stat;
>   	int rc;
> -	u32 port_no;
>   
>   	i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
>   	if (!i2c)
> @@ -678,10 +694,16 @@ static int fsi_i2c_probe(struct device *dev)
>   	if (rc)
>   		return rc;
>   
> -	/* Add adapter for each i2c port of the master. */
> -	for_each_available_child_of_node(dev->of_node, np) {
> -		rc = of_property_read_u32(np, "reg", &port_no);
> -		if (rc || port_no > USHRT_MAX)
> +	rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat);
> +	if (rc)
> +		return rc;
> +
> +	ports = FIELD_GET(I2C_STAT_MAX_PORT, stat) + 1;
> +	dev_dbg(dev, "I2C master has %d ports\n", ports);
> +
> +	for (port_no = 0; port_no < ports; port_no++) {
> +		np = fsi_i2c_find_port_of_node(dev->of_node, port_no);
> +		if (np && !of_device_is_available(np))
>   			continue;
>   
>   		port = kzalloc(sizeof(*port), GFP_KERNEL);