From 9a94241afcc9a481691a9c29b7460217925b59b8 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Wed, 11 Aug 2010 18:20:56 +0200 Subject: i2c: Add support for custom probe function The probe method used by i2c_new_probed_device() may not be suitable for all cases. Let the caller provide its own, optional probe function. Signed-off-by: Jean Delvare Acked-by: Mauro Carvalho Chehab --- include/linux/i2c.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 38dd4025aa4..59a9f3cdc0b 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -284,12 +284,15 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info); /* If you don't know the exact address of an I2C device, use this variant * instead, which can probe for device presence in a list of possible - * addresses. + * addresses. The "probe" callback function is optional. If it is provided, + * it must return 1 on successful probe, 0 otherwise. If it is not provided, + * a default probing method is used. */ extern struct i2c_client * i2c_new_probed_device(struct i2c_adapter *adap, struct i2c_board_info *info, - unsigned short const *addr_list); + unsigned short const *addr_list, + int (*probe)(struct i2c_adapter *, unsigned short addr)); /* For devices that use several addresses, use i2c_new_dummy() to make * client handles for the extra addresses. -- cgit v1.2.3 From d44f19d586b6113fb5db10e1a36457f0db3b01aa Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Wed, 11 Aug 2010 18:20:57 +0200 Subject: V4L/DVB: Use custom I2C probing function mechanism Now that i2c-core offers the possibility to provide custom probing function for I2C devices, let's make use of it. Signed-off-by: Jean Delvare Acked-by: Mauro Carvalho Chehab --- include/linux/i2c.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 59a9f3cdc0b..c8627e453e9 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -294,6 +294,9 @@ i2c_new_probed_device(struct i2c_adapter *adap, unsigned short const *addr_list, int (*probe)(struct i2c_adapter *, unsigned short addr)); +/* Common custom probe functions */ +extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); + /* For devices that use several addresses, use i2c_new_dummy() to make * client handles for the extra addresses. */ -- cgit v1.2.3 From fe61e07e9ebc890c70d97a1f72ddaad4bee2d848 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Wed, 11 Aug 2010 18:20:58 +0200 Subject: i2c: Move adapter locking helpers to i2c-core Uninline i2c adapter locking helper functions, move them to i2c-core, and use them in i2c-core itself. The functions are still exported for external users. This makes future updates to the locking model (which will be needed for multiplexing support) possible and transparent. Signed-off-by: Jean Delvare Cc: Michael Lawnick --- include/linux/i2c.h | 20 +++----------------- 1 file changed, 3 insertions(+), 17 deletions(-) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index c8627e453e9..5bf0f4beea3 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -382,23 +382,9 @@ static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data) dev_set_drvdata(&dev->dev, data); } -/** - * i2c_lock_adapter - Prevent access to an I2C bus segment - * @adapter: Target I2C bus segment - */ -static inline void i2c_lock_adapter(struct i2c_adapter *adapter) -{ - rt_mutex_lock(&adapter->bus_lock); -} - -/** - * i2c_unlock_adapter - Reauthorize access to an I2C bus segment - * @adapter: Target I2C bus segment - */ -static inline void i2c_unlock_adapter(struct i2c_adapter *adapter) -{ - rt_mutex_unlock(&adapter->bus_lock); -} +/* Adapter locking functions, exported for shared pin cases */ +void i2c_lock_adapter(struct i2c_adapter *); +void i2c_unlock_adapter(struct i2c_adapter *); /*flags for the client struct: */ #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ -- cgit v1.2.3 From dafc50d141c27959dbd3a1cfe9857a86d23402a7 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Wed, 11 Aug 2010 18:21:01 +0200 Subject: i2c: Use a separate mutex for userspace client lists Moving userspace-instantiated clients to separate lists wasn't nearly enough to avoid deadlocks in multiplexed bus cases. We also want to have a dedicated mutex to protect each list. Signed-off-by: Jean Delvare Cc: Michael Lawnick --- include/linux/i2c.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 5bf0f4beea3..798bad8741e 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -368,6 +368,7 @@ struct i2c_adapter { char name[48]; struct completion dev_released; + struct mutex userspace_clients_lock; struct list_head userspace_clients; }; #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) -- cgit v1.2.3 From 0826374bff57411d239f2fcb15da3c35af0a93cd Mon Sep 17 00:00:00 2001 From: Michael Lawnick Date: Wed, 11 Aug 2010 18:21:02 +0200 Subject: i2c: Multiplexed I2C bus core support Add multiplexed bus core support. I2C multiplexer and switches like pca954x get instantiated as new adapters per port. Signed-off-by: Michael Lawnick Acked-by: Rodolfo Giometti Signed-off-by: Jean Delvare --- include/linux/i2c-mux.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/i2c.h | 8 ++++++++ 2 files changed, 54 insertions(+) create mode 100644 include/linux/i2c-mux.h (limited to 'include') diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h new file mode 100644 index 00000000000..34536effd65 --- /dev/null +++ b/include/linux/i2c-mux.h @@ -0,0 +1,46 @@ +/* + * + * i2c-mux.h - functions for the i2c-bus mux support + * + * Copyright (c) 2008-2009 Rodolfo Giometti + * Copyright (c) 2008-2009 Eurotech S.p.A. + * Michael Lawnick + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#ifndef _LINUX_I2C_MUX_H +#define _LINUX_I2C_MUX_H + +#ifdef __KERNEL__ + +/* + * Called to create a i2c bus on a multiplexed bus segment. + * The mux_dev and chan_id parameters are passed to the select + * and deselect callback functions to perform hardware-specific + * mux control. + */ +struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, + void *mux_dev, u32 force_nr, u32 chan_id, + int (*select) (struct i2c_adapter *, + void *mux_dev, u32 chan_id), + int (*deselect) (struct i2c_adapter *, + void *mux_dev, u32 chan_id)); + +int i2c_del_mux_adapter(struct i2c_adapter *adap); + +#endif /* __KERNEL__ */ + +#endif /* _LINUX_I2C_MUX_H */ diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 798bad8741e..4bae0b72ed3 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -37,6 +37,7 @@ #include /* for struct device_node */ extern struct bus_type i2c_bus_type; +extern struct device_type i2c_adapter_type; /* --- General options ------------------------------------------------ */ @@ -383,6 +384,13 @@ static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data) dev_set_drvdata(&dev->dev, data); } +static inline int i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter) +{ + return adapter->dev.parent != NULL + && adapter->dev.parent->bus == &i2c_bus_type + && adapter->dev.parent->type == &i2c_adapter_type; +} + /* Adapter locking functions, exported for shared pin cases */ void i2c_lock_adapter(struct i2c_adapter *); void i2c_unlock_adapter(struct i2c_adapter *); -- cgit v1.2.3 From 7f528135da9704d67db1f727162024b078e1cd8f Mon Sep 17 00:00:00 2001 From: Michael Lawnick Date: Wed, 11 Aug 2010 18:21:03 +0200 Subject: i2c: I2C bus multiplexer driver pca954x I2C driver for PCA954x I2C multiplexer series. Signed-off-by: Michael Lawnick Acked-by: Rodolfo Giometti Signed-off-by: Jean Delvare --- include/linux/i2c/pca954x.h | 47 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 include/linux/i2c/pca954x.h (limited to 'include') diff --git a/include/linux/i2c/pca954x.h b/include/linux/i2c/pca954x.h new file mode 100644 index 00000000000..28f1f8d5ab1 --- /dev/null +++ b/include/linux/i2c/pca954x.h @@ -0,0 +1,47 @@ +/* + * + * pca954x.h - I2C multiplexer/switch support + * + * Copyright (c) 2008-2009 Rodolfo Giometti + * Copyright (c) 2008-2009 Eurotech S.p.A. + * Michael Lawnick + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + + +#ifndef _LINUX_I2C_PCA954X_H +#define _LINUX_I2C_PCA954X_H + +/* Platform data for the PCA954x I2C multiplexers */ + +/* Per channel initialisation data: + * @adap_id: bus number for the adapter. 0 = don't care + * @deselect_on_exit: set this entry to 1, if your H/W needs deselection + * of this channel after transaction. + * + */ +struct pca954x_platform_mode { + int adap_id; + unsigned int deselect_on_exit:1; +}; + +/* Per mux/switch data, used with i2c_register_board_info */ +struct pca954x_platform_data { + struct pca954x_platform_mode *modes; + int num_modes; +}; + +#endif /* _LINUX_I2C_PCA954X_H */ -- cgit v1.2.3