From 2187f03a9576c4fb8342deed912b5ba6fcf98cba Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Mon, 5 Jan 2015 15:35:39 +0100 Subject: i2c: add quirk structure to describe adapter flaws The number of I2C adapters which are not fully I2C compatible is rising, sadly. Drivers usually do handle the flaws, still the user receives only some errno for a transfer which normally can be expected to work. This patch introduces a formal description of flaws. One advantage is that the core can check before the actual transfer if the messages could be transferred at all. This is done in the next patch. Another advantage is that we can pass this information to the user so the restrictions are exactly known and further actions can be based on that. This will be done later after some stabilization period for this description. Signed-off-by: Wolfram Sang Tested-by: Ray Jui Tested-by: Ivan T. Ivanov Tested-by: Neelesh Gupta Tested-By: Ludovic Desroches --- include/linux/i2c.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'include/linux') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index f17da50402a4..243d1a1d78b2 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -449,6 +449,48 @@ int i2c_recover_bus(struct i2c_adapter *adap); int i2c_generic_gpio_recovery(struct i2c_adapter *adap); int i2c_generic_scl_recovery(struct i2c_adapter *adap); +/** + * struct i2c_adapter_quirks - describe flaws of an i2c adapter + * @flags: see I2C_AQ_* for possible flags and read below + * @max_num_msgs: maximum number of messages per transfer + * @max_write_len: maximum length of a write message + * @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 + * + * Note about combined messages: Some I2C controllers can only send one message + * per transfer, plus something called combined message or write-then-read. + * This is (usually) a small write message followed by a read message and + * barely enough to access register based devices like EEPROMs. There is a flag + * to support this mode. It implies max_num_msg = 2 and does the length checks + * with max_comb_*_len because combined message mode usually has its own + * limitations. Because of HW implementations, some controllers can actually do + * write-then-anything or other variants. To support that, write-then-read has + * been broken out into smaller bits like write-first and read-second which can + * be combined as needed. + */ + +struct i2c_adapter_quirks { + u64 flags; + int max_num_msgs; + u16 max_write_len; + u16 max_read_len; + u16 max_comb_1st_msg_len; + u16 max_comb_2nd_msg_len; +}; + +/* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */ +#define I2C_AQ_COMB BIT(0) +/* first combined message must be write */ +#define I2C_AQ_COMB_WRITE_FIRST BIT(1) +/* second combined message must be read */ +#define I2C_AQ_COMB_READ_SECOND BIT(2) +/* both combined messages must have the same target address */ +#define I2C_AQ_COMB_SAME_ADDR BIT(3) +/* convenience macro for typical write-then read case */ +#define I2C_AQ_COMB_WRITE_THEN_READ (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \ + I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR) + /* * i2c_adapter is the structure used to identify a physical i2c bus along * with the access algorithms necessary to access it. @@ -474,6 +516,7 @@ struct i2c_adapter { struct list_head userspace_clients; struct i2c_bus_recovery_info *bus_recovery_info; + const struct i2c_adapter_quirks *quirks; }; #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) -- cgit v1.2.3 From 351d224f64afc1b3b359a1738b7d4600c7e64061 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Thu, 12 Mar 2015 17:17:58 +0100 Subject: of: base: add function to get highest id of an alias stem I2C supports adding adapters using either a dynamic or fixed id. The latter is provided by aliases in the DT case. To prevent id collisions of those two types, install this function which gives us the highest fixed id, so we can then let the dynamically created ones come after this highest number. Signed-off-by: Wolfram Sang Acked-by: Rob Herring Signed-off-by: Wolfram Sang --- include/linux/of.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux') diff --git a/include/linux/of.h b/include/linux/of.h index dfde07e77a63..9bfcc18ceab3 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -332,6 +332,7 @@ extern int of_count_phandle_with_args(const struct device_node *np, extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)); extern int of_alias_get_id(struct device_node *np, const char *stem); +extern int of_alias_get_highest_id(const char *stem); extern int of_machine_is_compatible(const char *compat); @@ -594,6 +595,11 @@ static inline int of_alias_get_id(struct device_node *np, const char *stem) return -ENOSYS; } +static inline int of_alias_get_highest_id(const char *stem) +{ + return -ENOSYS; +} + static inline int of_machine_is_compatible(const char *compat) { return 0; -- cgit v1.2.3 From 5b77d162a3d7359a8a8d83776720da065bf4e77b Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Mon, 23 Mar 2015 09:26:36 +0100 Subject: i2c: slave: rework the slave API MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit After more discussion, brave users, and additional datasheet evaluation, some API updates for the new I2C slave framework became imminent. The slave events now get some easier to understand naming. Also, the event handling has been simplified to only need a single call to the slave callback when an action by the backend is required. Reported-by: Uwe Kleine-König Signed-off-by: Wolfram Sang Acked-by: Geert Uytterhoeven Acked-by: Uwe Kleine-König Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 243d1a1d78b2..c5e4bb2c5759 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -253,10 +253,10 @@ static inline void i2c_set_clientdata(struct i2c_client *dev, void *data) #if IS_ENABLED(CONFIG_I2C_SLAVE) enum i2c_slave_event { - I2C_SLAVE_REQ_READ_START, - I2C_SLAVE_REQ_READ_END, - I2C_SLAVE_REQ_WRITE_START, - I2C_SLAVE_REQ_WRITE_END, + I2C_SLAVE_READ_REQUESTED, + I2C_SLAVE_WRITE_REQUESTED, + I2C_SLAVE_READ_PROCESSED, + I2C_SLAVE_WRITE_RECEIVED, I2C_SLAVE_STOP, }; -- cgit v1.2.3 From 2b2190a375d796a5ad9ec557cb51269f36b264d4 Mon Sep 17 00:00:00 2001 From: Grygorii Strashko Date: Mon, 6 Apr 2015 15:38:39 +0300 Subject: i2c: change input parameter to i2c_adapter for prepare/unprepare_recovery MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch changes type of input parameter for prepare/unprepare_recovery() callbacks from struct i2c_bus_recovery_info * to struct i2c_adapter *. This allows to simplify implementation of these callbacks and avoid type conversations from i2c_bus_recovery_info to i2c_adapter. The i2c_bus_recovery_info can be simply retrieved from struct i2c_adapter which contains pointer on it. There are no users currently, so this is safe to do. Acked-by: Uwe Kleine-König Acked-by: Alexander Sverdlin Signed-off-by: Grygorii Strashko Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index c5e4bb2c5759..898033f41d76 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -435,8 +435,8 @@ struct i2c_bus_recovery_info { void (*set_scl)(struct i2c_adapter *, int val); int (*get_sda)(struct i2c_adapter *); - void (*prepare_recovery)(struct i2c_bus_recovery_info *bri); - void (*unprepare_recovery)(struct i2c_bus_recovery_info *bri); + void (*prepare_recovery)(struct i2c_adapter *); + void (*unprepare_recovery)(struct i2c_adapter *); /* gpio recovery */ int scl_gpio; -- cgit v1.2.3 From 7ef97e9a312c359a2b32a7b5d918c60f238b69b2 Mon Sep 17 00:00:00 2001 From: Grygorii Strashko Date: Mon, 6 Apr 2015 15:38:41 +0300 Subject: i2c: davinci: use ICPFUNC to toggle I2C as gpio for bus recovery MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Having a board where the I2C bus locks up occasionally made it clear that the bus recovery in the i2c-davinci driver will only work on some boards, because on regular boards, this will only toggle GPIO lines that aren't muxed to the actual pins. The I2C controller on SoCs like da850 (and da830), Keystone 2 has the built-in capability to bit-bang its lines by using the ICPFUNC registers of the i2c controller. Implement the suggested procedure by toggling SCL and checking SDA using the ICPFUNC registers of the I2C controller when present. Allow platforms to indicate the presence of the ICPFUNC registers with a has_pfunc platform data flag and add optional DT property "ti,has-pfunc" to indicate the same in DT. Reviewed-by: Uwe Kleine-König Acked-by: Alexander Sverdlin Tested-by: Michael Lawnick Signed-off-by: Ben Gardiner Signed-off-by: Mike Looijmans [grygorii.strashko@ti.com: combined patches from Ben Gardiner and Mike Looijmans and reimplemented ICPFUNC bus recovery using I2C bus recovery infrastructure] Signed-off-by: Grygorii Strashko Signed-off-by: Wolfram Sang --- include/linux/platform_data/i2c-davinci.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/platform_data/i2c-davinci.h b/include/linux/platform_data/i2c-davinci.h index 2312d197dfb7..89fd34727a24 100644 --- a/include/linux/platform_data/i2c-davinci.h +++ b/include/linux/platform_data/i2c-davinci.h @@ -18,6 +18,7 @@ struct davinci_i2c_platform_data { unsigned int bus_delay; /* post-transaction delay (usec) */ unsigned int sda_pin; /* GPIO pin ID to use for SDA */ unsigned int scl_pin; /* GPIO pin ID to use for SCL */ + bool has_pfunc; /*chip has a ICPFUNC register */ }; /* for board setup code */ -- cgit v1.2.3