From: Farouk Bouabid <farouk.bouabid@cherry.de>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>,
Peter Rosin <peda@axentia.se>,
Andi Shyti <andi.shyti@kernel.org>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Conor Dooley <conor+dt@kernel.org>,
Farouk Bouabid <farouk.bouabid@cherry.de>,
Quentin Schulz <quentin.schulz@cherry.de>,
Heiko Stuebner <heiko@sntech.de>,
Quentin Schulz <quentin.schulz@theobroma-systems.com>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org
Subject: [PATCH v2 1/7] i2c: mux: add the ability to share mux core address with child nodes
Date: Mon, 06 May 2024 13:37:52 +0200 [thread overview]
Message-ID: <20240506-dev-mule-i2c-mux-v2-1-a91c954f65d7@cherry.de> (raw)
In-Reply-To: <20240506-dev-mule-i2c-mux-v2-0-a91c954f65d7@cherry.de>
Allow the mux core (if it's an i2c device) to have the same address as
a child device. This is useful when the mux core can only use an i2c
address that is used by a child device because no other addresses are
free to use. eg. the mux core can only use address 0x18 which is used by
amc6821 connected to the mux.
Signed-off-by: Farouk Bouabid <farouk.bouabid@cherry.de>
---
drivers/i2c/i2c-core-base.c | 6 +++++-
drivers/i2c/i2c-mux.c | 25 ++++++++++++++++++++++++-
include/linux/i2c-mux.h | 1 +
include/linux/i2c.h | 7 +++++++
4 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index ff5c486a1dbb..ce2425b0486d 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -821,9 +821,13 @@ static int i2c_check_mux_children(struct device *dev, void *addrp)
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
+ bool skip_check = false;
int result = 0;
- if (parent)
+ if (adapter->quirks && adapter->quirks->flags & I2C_AQ_SKIP_ADDR_CHECK)
+ skip_check = adapter->quirks->skip_addr_in_parent == addr;
+
+ if (parent && !skip_check)
result = i2c_check_mux_parents(parent, addr);
if (!result)
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 57ff09f18c37..bdb75a130cab 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -334,7 +334,30 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
priv->adap.dev.parent = &parent->dev;
priv->adap.retries = parent->retries;
priv->adap.timeout = parent->timeout;
- priv->adap.quirks = parent->quirks;
+ /*
+ * When creating the adapter, the node devices are checked for i2c address
+ * match with other devices on the parent adapter, among which is the mux core itself.
+ * If a match is found the node device is not probed successfully.
+ * Allow the mux to have the same address as a child device by skipping this check.
+ */
+ if (muxc->share_addr_with_children && muxc->dev->type == &i2c_client_type) {
+ struct i2c_adapter_quirks *quirks = devm_kzalloc(muxc->dev,
+ sizeof(*quirks), GFP_KERNEL);
+ struct i2c_client *client = to_i2c_client(muxc->dev);
+
+ if (!quirks)
+ return -ENOMEM;
+
+ if (parent->quirks)
+ memcpy(quirks, parent->quirks, sizeof(*quirks));
+
+ quirks->flags |= I2C_AQ_SKIP_ADDR_CHECK;
+ quirks->skip_addr_in_parent = client->addr;
+ priv->adap.quirks = quirks;
+ } else {
+ priv->adap.quirks = parent->quirks;
+ }
+
if (muxc->mux_locked)
priv->adap.lock_ops = &i2c_mux_lock_ops;
else
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index 98ef73b7c8fd..17ac68bf1703 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -21,6 +21,7 @@ struct i2c_mux_core {
unsigned int mux_locked:1;
unsigned int arbitrator:1;
unsigned int gate:1;
+ unsigned int share_addr_with_children:1;
void *priv;
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 5e6cd43a6dbd..c3acbaaadae9 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -670,6 +670,7 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap);
* @max_read_len: maximum length of a read message
* @max_comb_1st_msg_len: maximum length of the first msg in a combined message
* @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
+ * @skip_addr_in_parent: No conflict check on parent adapter for a given address
*
* Note about combined messages: Some I2C controllers can only send one message
* per transfer, plus something called combined message or write-then-read.
@@ -690,6 +691,7 @@ struct i2c_adapter_quirks {
u16 max_read_len;
u16 max_comb_1st_msg_len;
u16 max_comb_2nd_msg_len;
+ unsigned short skip_addr_in_parent;
};
/* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
@@ -711,6 +713,11 @@ struct i2c_adapter_quirks {
#define I2C_AQ_NO_ZERO_LEN (I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
/* adapter cannot do repeated START */
#define I2C_AQ_NO_REP_START BIT(7)
+/**
+ * do not check for conflict on a given address
+ * used accordingly with "struct i2c_adapter_quirks.skip_addr_in_parent"
+ */
+#define I2C_AQ_SKIP_ADDR_CHECK BIT(8)
/*
* i2c_adapter is the structure used to identify a physical i2c bus along
--
2.34.1
next prev parent reply other threads:[~2024-05-06 12:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 11:37 [PATCH v2 0/7] Add Mule I2C multiplexer support Farouk Bouabid
2024-05-06 11:37 ` Farouk Bouabid [this message]
2024-05-06 21:26 ` [PATCH v2 1/7] i2c: mux: add the ability to share mux core address with child nodes Peter Rosin
2024-05-07 9:48 ` Quentin Schulz
2024-05-06 11:37 ` [PATCH v2 2/7] dt-bindings: i2c: mux: mule: add dt-bindings for mule i2c multiplexer Farouk Bouabid
2024-05-06 20:26 ` Rob Herring (Arm)
2024-05-06 11:37 ` [PATCH v2 3/7] i2c: muxes: add support " Farouk Bouabid
2024-05-06 11:37 ` [PATCH v2 4/7] arm64: dts: rockchip: add mule i2c mux (0x18) on rk3399-puma Farouk Bouabid
2024-05-06 11:37 ` [PATCH v2 5/7] arm64: dts: rockchip: add mule i2c mux (0x18) on rk3588-tiger Farouk Bouabid
2024-05-06 11:37 ` [PATCH v2 6/7] arm64: dts: rockchip: add mule i2c mux (0x18) on px30-ringneck Farouk Bouabid
2024-05-06 11:37 ` [PATCH v2 7/7] arm64: dts: rockchip: add mule i2c mux (0x18) on rk3588-jaguar Farouk Bouabid
2024-05-06 20:40 ` [PATCH v2 0/7] Add Mule I2C multiplexer support Rob Herring (Arm)
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