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i2c: use client addresses directly in ATR interface

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The I2C Address Translator (ATR) module defines mappings from i2c_client
structs to aliases. However, only the physical address of each i2c_client
struct is actually relevant to the workings of the ATR module. Moreover,
some drivers require address translation functionality but do not allocate
i2c_client structs, accessing the adapter directly instead. The SFP
subsystem is an example of this.

Replace the "i2c_client" field of the i2c_atr_alias_pair struct with a u16
"addr" field. Rewrite helper functions and callbacks as needed.

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This commit is contained in:
Romain Gantois 2025-03-06 17:23:25 +01:00 committed by Wolfram Sang
parent 3ec29d51b5
commit 818bd489f1
3 changed files with 41 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
drivers/i2c/i2c-atr.c
View File

@ -21,16 +21,16 @@
#define ATR_MAX_SYMLINK_LEN 11 /* Longest name is 10 chars: "channel-99" */
/**
* struct i2c_atr_alias_pair - Holds the alias assigned to a client.
* struct i2c_atr_alias_pair - Holds the alias assigned to a client address.
* @node: List node
* @client: Pointer to the client on the child bus
* @addr: Address of the client on the child bus.
* @alias: I2C alias address assigned by the driver.
* This is the address that will be used to issue I2C transactions
* on the parent (physical) bus.
*/
struct i2c_atr_alias_pair {
struct list_head node;
const struct i2c_client *client;
u16 addr;
u16 alias;
};
@ -97,27 +97,13 @@ struct i2c_atr {
struct i2c_adapter *adapter[] __counted_by(max_adapters);
};
static struct i2c_atr_alias_pair *
i2c_atr_find_mapping_by_client(const struct list_head *list,
const struct i2c_client *client)
{
struct i2c_atr_alias_pair *c2a;
list_for_each_entry(c2a, list, node) {
if (c2a->client == client)
return c2a;
}
return NULL;
}
static struct i2c_atr_alias_pair *
i2c_atr_find_mapping_by_addr(const struct list_head *list, u16 phys_addr)
{
struct i2c_atr_alias_pair *c2a;
list_for_each_entry(c2a, list, node) {
if (c2a->client->addr == phys_addr)
if (c2a->addr == phys_addr)
return c2a;
}
@ -313,8 +299,8 @@ static void i2c_atr_release_alias(struct i2c_atr *atr, u16 alias)
dev_warn(atr->dev, "Unable to find mapped alias\n");
}
static int i2c_atr_attach_client(struct i2c_adapter *adapter,
const struct i2c_client *client)
static int i2c_atr_attach_addr(struct i2c_adapter *adapter,
u16 addr)
{
struct i2c_atr_chan *chan = adapter->algo_data;
struct i2c_atr *atr = chan->atr;
@ -334,14 +320,14 @@ static int i2c_atr_attach_client(struct i2c_adapter *adapter,
goto err_release_alias;
}
ret = atr->ops->attach_client(atr, chan->chan_id, client, alias);
ret = atr->ops->attach_addr(atr, chan->chan_id, addr, alias);
if (ret)
goto err_free;
dev_dbg(atr->dev, "chan%u: client 0x%02x mapped at alias 0x%02x (%s)\n",
chan->chan_id, client->addr, alias, client->name);
dev_dbg(atr->dev, "chan%u: using alias 0x%02x for addr 0x%02x\n",
chan->chan_id, alias, addr);
c2a->client = client;
c2a->addr = addr;
c2a->alias = alias;
list_add(&c2a->node, &chan->alias_list);
@ -355,16 +341,16 @@ static int i2c_atr_attach_client(struct i2c_adapter *adapter,
return ret;
}
static void i2c_atr_detach_client(struct i2c_adapter *adapter,
const struct i2c_client *client)
static void i2c_atr_detach_addr(struct i2c_adapter *adapter,
u16 addr)
{
struct i2c_atr_chan *chan = adapter->algo_data;
struct i2c_atr *atr = chan->atr;
struct i2c_atr_alias_pair *c2a;
atr->ops->detach_client(atr, chan->chan_id, client);
atr->ops->detach_addr(atr, chan->chan_id, addr);
c2a = i2c_atr_find_mapping_by_client(&chan->alias_list, client);
c2a = i2c_atr_find_mapping_by_addr(&chan->alias_list, addr);
if (!c2a) {
/* This should never happen */
dev_warn(atr->dev, "Unable to find address mapping\n");
@ -374,8 +360,8 @@ static void i2c_atr_detach_client(struct i2c_adapter *adapter,
i2c_atr_release_alias(atr, c2a->alias);
dev_dbg(atr->dev,
"chan%u: client 0x%02x unmapped from alias 0x%02x (%s)\n",
chan->chan_id, client->addr, c2a->alias, client->name);
"chan%u: detached alias 0x%02x from addr 0x%02x\n",
chan->chan_id, c2a->alias, addr);
list_del(&c2a->node);
kfree(c2a);
@ -405,7 +391,7 @@ static int i2c_atr_bus_notifier_call(struct notifier_block *nb,
switch (event) {
case BUS_NOTIFY_ADD_DEVICE:
ret = i2c_atr_attach_client(client->adapter, client);
ret = i2c_atr_attach_addr(client->adapter, client->addr);
if (ret)
dev_err(atr->dev,
"Failed to attach remote client '%s': %d\n",
@ -413,7 +399,7 @@ static int i2c_atr_bus_notifier_call(struct notifier_block *nb,
break;
case BUS_NOTIFY_REMOVED_DEVICE:
i2c_atr_detach_client(client->adapter, client);
i2c_atr_detach_addr(client->adapter, client->addr);
break;
default:
@ -506,7 +492,7 @@ struct i2c_atr *i2c_atr_new(struct i2c_adapter *parent, struct device *dev,
if (max_adapters > ATR_MAX_ADAPTERS)
return ERR_PTR(-EINVAL);
if (!ops || !ops->attach_client || !ops->detach_client)
if (!ops || !ops->attach_addr || !ops->detach_addr)
return ERR_PTR(-EINVAL);
atr = kzalloc(struct_size(atr, adapter, max_adapters), GFP_KERNEL);

24
drivers/media/i2c/ds90ub960.c
View File

@ -1049,8 +1049,8 @@ static int ub960_ind_update_bits(struct ub960_data *priv, u8 block, u8 reg,
* I2C-ATR (address translator)
*/
static int ub960_atr_attach_client(struct i2c_atr *atr, u32 chan_id,
const struct i2c_client *client, u16 alias)
static int ub960_atr_attach_addr(struct i2c_atr *atr, u32 chan_id,
u16 addr, u16 alias)
{
struct ub960_data *priv = i2c_atr_get_driver_data(atr);
struct ub960_rxport *rxport = priv->rxports[chan_id];
@ -1069,21 +1069,21 @@ static int ub960_atr_attach_client(struct i2c_atr *atr, u32 chan_id,
return -EADDRNOTAVAIL;
}
rxport->aliased_addrs[reg_idx] = client->addr;
rxport->aliased_addrs[reg_idx] = addr;
ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ID(reg_idx),
client->addr << 1);
addr << 1);
ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ALIAS(reg_idx),
alias << 1);
dev_dbg(dev, "rx%u: client 0x%02x assigned alias 0x%02x at slot %u\n",
rxport->nport, client->addr, alias, reg_idx);
rxport->nport, addr, alias, reg_idx);
return 0;
}
static void ub960_atr_detach_client(struct i2c_atr *atr, u32 chan_id,
const struct i2c_client *client)
static void ub960_atr_detach_addr(struct i2c_atr *atr, u32 chan_id,
u16 addr)
{
struct ub960_data *priv = i2c_atr_get_driver_data(atr);
struct ub960_rxport *rxport = priv->rxports[chan_id];
@ -1093,13 +1093,13 @@ static void ub960_atr_detach_client(struct i2c_atr *atr, u32 chan_id,
guard(mutex)(&rxport->aliased_addrs_lock);
for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_addrs); reg_idx++) {
if (rxport->aliased_addrs[reg_idx] == client->addr)
if (rxport->aliased_addrs[reg_idx] == addr)
break;
}
if (reg_idx == ARRAY_SIZE(rxport->aliased_addrs)) {
dev_err(dev, "rx%u: client 0x%02x is not mapped!\n",
rxport->nport, client->addr);
rxport->nport, addr);
return;
}
@ -1108,12 +1108,12 @@ static void ub960_atr_detach_client(struct i2c_atr *atr, u32 chan_id,
ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ALIAS(reg_idx), 0);
dev_dbg(dev, "rx%u: client 0x%02x released at slot %u\n", rxport->nport,
client->addr, reg_idx);
addr, reg_idx);
}
static const struct i2c_atr_ops ub960_atr_ops = {
.attach_client = ub960_atr_attach_client,
.detach_client = ub960_atr_detach_client,
.attach_addr = ub960_atr_attach_addr,
.detach_addr = ub960_atr_detach_addr,
};
static int ub960_init_atr(struct ub960_data *priv)

20
include/linux/i2c-atr.h
View File

@ -20,20 +20,20 @@ struct i2c_atr;
/**
* struct i2c_atr_ops - Callbacks from ATR to the device driver.
* @attach_client: Notify the driver of a new device connected on a child
* bus, with the alias assigned to it. The driver must
* configure the hardware to use the alias.
* @detach_client: Notify the driver of a device getting disconnected. The
* driver must configure the hardware to stop using the
* alias.
* @attach_addr: Notify the driver of a new device connected on a child
* bus, with the alias assigned to it. The driver must
* configure the hardware to use the alias.
* @detach_addr: Notify the driver of a device getting disconnected. The
* driver must configure the hardware to stop using the
* alias.
*
* All these functions return 0 on success, a negative error code otherwise.
*/
struct i2c_atr_ops {
int (*attach_client)(struct i2c_atr *atr, u32 chan_id,
const struct i2c_client *client, u16 alias);
void (*detach_client)(struct i2c_atr *atr, u32 chan_id,
const struct i2c_client *client);
int (*attach_addr)(struct i2c_atr *atr, u32 chan_id,
u16 addr, u16 alias);
void (*detach_addr)(struct i2c_atr *atr, u32 chan_id,
u16 addr);
};
/**