From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: [RFC PATCH 7/7] i2c: core: hand over reserved devices when requesting ancillary addresses Date: Thu, 20 Feb 2020 18:24:03 +0100 Message-ID: <20200220172403.26062-8-wsa+renesas@sang-engineering.com> References: <20200220172403.26062-1-wsa+renesas@sang-engineering.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200220172403.26062-1-wsa+renesas@sang-engineering.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-i2c@vger.kernel.org Cc: linux-renesas-soc@vger.kernel.org, linux-i3c@lists.infradead.org, Kieran Bingham , =?UTF-8?q?Niklas=20S=C3=B6derlund?= , Luca Ceresoli , Jacopo Mondi , Laurent Pinchart , Vladimir Zapolskiy , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Wolfram Sang List-Id: linux-i2c@vger.kernel.org With i2c_new_ancillary_address, we can check if the intended driver is requesting a reserved address. Update the function to do these checks. If the check passes, the "reserved" device will become a regular "dummy" device. Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core-base.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 4000a4384306..ba325f8107a3 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -975,6 +975,8 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, u16 default_addr) { struct device_node *np = client->dev.of_node; + struct device *reserved_dev, *adapter_dev = &client->adapter->dev; + struct i2c_client *reserved_client; u32 addr = default_addr; int i; @@ -984,7 +986,21 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, of_property_read_u32_index(np, "reg", i, &addr); } - dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); + dev_info(adapter_dev, "Address for %s : 0x%x\n", name, addr); + + /* No need to scan muxes, siblings must sit on the same adapter */ + reserved_dev = device_find_child(adapter_dev, &addr, __i2c_check_addr_busy); + reserved_client = i2c_verify_client(reserved_dev); + + if (reserved_client) { + if (reserved_client->dev.of_node != np || + strcmp(reserved_client->name, I2C_RESERVED_DRV_NAME) != 0) + return ERR_PTR(-EBUSY); + + strlcpy(reserved_client->name, I2C_DUMMY_DRV_NAME, sizeof(client->name)); + return reserved_client; + } + return i2c_new_dummy_device(client->adapter, addr); } EXPORT_SYMBOL_GPL(i2c_new_ancillary_device); -- 2.20.1