From 749de3dac5e4d65cbed3b58f89c56883e31d1a5a Mon Sep 17 00:00:00 2001 From: Nicola Corna Date: Thu, 29 Oct 2015 12:34:23 +0100 Subject: i2c: add i2c quirk flag for unsupported clock stretching Add I2C_AQ_NO_CLK_STRETCH quirk flag, to be used when clock stretching is not supported. Signed-off-by: Nicola Corna Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 768063baafbf..96970024883f 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -493,6 +493,8 @@ struct i2c_adapter_quirks { /* 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) +/* clock stretching is not supported */ +#define I2C_AQ_NO_CLK_STRETCH BIT(4) /* * i2c_adapter is the structure used to identify a physical i2c bus along -- cgit v1.2.3 From cfa576db834cacc1bb01bc41b2f61a8b578e67c5 Mon Sep 17 00:00:00 2001 From: Nicola Corna Date: Thu, 29 Oct 2015 12:34:26 +0100 Subject: i2c: add i2c_check_quirks helper function This patch adds a i2c_check_quirks helper function to check the quirk flags of an i2c adapter, in a similar way to i2c_check_functionality. Signed-off-by: Nicola Corna Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 96970024883f..51028f351d13 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -617,6 +617,20 @@ static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func) return (func & i2c_get_functionality(adap)) == func; } +/** + * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter + * @adap: i2c adapter + * @quirks: quirk flags + * + * Return: true if the adapter has all the specified quirk flags, false if not + */ +static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks) +{ + if (!adap->quirks) + return false; + return (adap->quirks->flags & quirks) == quirks; +} + /* Return the adapter number for a specific adapter */ static inline int i2c_adapter_id(struct i2c_adapter *adap) { -- cgit v1.2.3 From e1dba01ca620bb0b3864d5237c1c597d9e012ebf Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Tue, 8 Dec 2015 10:37:46 +0100 Subject: i2c: add generic routine to parse DT for timing information Inspired from the i2c-rk3x driver (thanks guys!) but refactored and extended. See built-in docs for further information. Signed-off-by: Wolfram Sang Reviewed-by: Mika Westerberg Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/i2c.h | 18 +++++++++++++++++ 2 files changed, 71 insertions(+) (limited to 'include') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index ba8eb087f224..b34c412bd2c2 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -53,6 +53,7 @@ #include #include #include +#include #include "i2c-core.h" @@ -1438,6 +1439,58 @@ static void of_i2c_register_devices(struct i2c_adapter *adap) } } +/** + * i2c_parse_fw_timings - get I2C related timing parameters from firmware + * @dev: The device to scan for I2C timing properties + * @t: the i2c_timings struct to be filled with values + * @use_defaults: bool to use sane defaults derived from the I2C specification + * when properties are not found, otherwise use 0 + * + * Scan the device for the generic I2C properties describing timing parameters + * for the signal and fill the given struct with the results. If a property was + * not found and use_defaults was true, then maximum timings are assumed which + * are derived from the I2C specification. If use_defaults is not used, the + * results will be 0, so drivers can apply their own defaults later. The latter + * is mainly intended for avoiding regressions of existing drivers which want + * to switch to this function. New drivers almost always should use the defaults. + */ + +void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) +{ + int ret; + + memset(t, 0, sizeof(*t)); + + ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz); + if (ret && use_defaults) + t->bus_freq_hz = 100000; + + ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns); + if (ret && use_defaults) { + if (t->bus_freq_hz <= 100000) + t->scl_rise_ns = 1000; + else if (t->bus_freq_hz <= 400000) + t->scl_rise_ns = 300; + else + t->scl_rise_ns = 120; + } + + ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns); + if (ret && use_defaults) { + if (t->bus_freq_hz <= 400000) + t->scl_fall_ns = 300; + else + t->scl_fall_ns = 120; + } + + device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns); + + ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns); + if (ret && use_defaults) + t->sda_fall_ns = t->scl_fall_ns; +} +EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); + static int of_dev_node_match(struct device *dev, void *data) { return dev->of_node == data; diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 51028f351d13..bc2b19ad9357 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -413,6 +413,22 @@ struct i2c_algorithm { #endif }; +/** + * struct i2c_timings - I2C timing information + * @bus_freq_hz: the bus frequency in Hz + * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification + * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification + * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns + * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification + */ +struct i2c_timings { + u32 bus_freq_hz; + u32 scl_rise_ns; + u32 scl_fall_ns; + u32 scl_int_delay_ns; + u32 sda_fall_ns; +}; + /** * struct i2c_bus_recovery_info - I2C bus recovery information * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or @@ -604,6 +620,7 @@ extern void i2c_clients_command(struct i2c_adapter *adap, extern struct i2c_adapter *i2c_get_adapter(int nr); extern void i2c_put_adapter(struct i2c_adapter *adap); +void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults); /* Return the functionality mask */ static inline u32 i2c_get_functionality(struct i2c_adapter *adap) @@ -660,6 +677,7 @@ extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node) /* must call i2c_put_adapter() when done with returned i2c_adapter device */ struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node); + #else static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) -- cgit v1.2.3 From c698d639f72b55686ec3518d2bc8dc5f2eca9354 Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Sun, 13 Dec 2015 15:33:19 -0500 Subject: i2c: create builtin_i2c_driver to avoid registration boilerplate In commit f309d4443130bf814e991f836e919dca22df37ae ("platform_device: better support builtin boilerplate avoidance") we introduced the builtin_driver macro. Here we use that support and extend it to I2C driver registration, so where a driver is clearly non-modular and builtin-only, we can register it in a similar fashion. And existing code that is clearly non-modular can be updated with the simple mapping of module_i2c_driver(...) ---> builtin_i2c_driver(...) We've essentially cloned the former to make the latter, and taken out the remove/module_exit parts since those never get used in a non-modular build of the code. A similar thing was done in commit b4eb6cdbbd13698704863f680c643c569909e1c2 ("PCI: Add builtin_pci_driver() to avoid registration boilerplate"). Signed-off-by: Paul Gortmaker Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index bc2b19ad9357..200cf13b00f6 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -655,7 +655,7 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap) } /** - * module_i2c_driver() - Helper macro for registering a I2C driver + * module_i2c_driver() - Helper macro for registering a modular I2C driver * @__i2c_driver: i2c_driver struct * * Helper macro for I2C drivers which do not do anything special in module @@ -666,6 +666,17 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap) module_driver(__i2c_driver, i2c_add_driver, \ i2c_del_driver) +/** + * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver + * @__i2c_driver: i2c_driver struct + * + * Helper macro for I2C drivers which do not do anything special in their + * init. This eliminates a lot of boilerplate. Each driver may only + * use this macro once, and calling it replaces device_initcall(). + */ +#define builtin_i2c_driver(__i2c_driver) \ + builtin_driver(__i2c_driver, i2c_add_driver) + #endif /* I2C */ #if IS_ENABLED(CONFIG_OF) -- cgit v1.2.3