i2c: core: add api to provide frequency mode strings

Some I2C drivers like Designware and HiSilicon will print the
bus frequency mode information, so add a public one that everyone
can make use of.

Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index c4c28b5..5c16083 100644 (file)
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -76,6 +76,27 @@ void i2c_transfer_trace_unreg(void)
        static_branch_dec(&i2c_trace_msg_key);
 }
 
+const char *i2c_freq_mode_string(u32 bus_freq_hz)
+{
+       switch (bus_freq_hz) {
+       case I2C_MAX_STANDARD_MODE_FREQ:
+               return "Standard Mode (100 kHz)";
+       case I2C_MAX_FAST_MODE_FREQ:
+               return "Fast Mode (400 kHz)";
+       case I2C_MAX_FAST_MODE_PLUS_FREQ:
+               return "Fast Mode Plus (1.0 MHz)";
+       case I2C_MAX_TURBO_MODE_FREQ:
+               return "Turbo Mode (1.4 MHz)";
+       case I2C_MAX_HIGH_SPEED_MODE_FREQ:
+               return "High Speed Mode (3.4 MHz)";
+       case I2C_MAX_ULTRA_FAST_MODE_FREQ:
+               return "Ultra Fast Mode (5.0 MHz)";
+       default:
+               return "Unknown Mode";
+       }
+}
+EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
+
 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
                                                const struct i2c_client *client)
 {

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index ce473dd..e5d8b9d 100644 (file)
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -51,6 +51,9 @@ struct module;
 struct property_entry;
 
 #if IS_ENABLED(CONFIG_I2C)
+/* Return the Frequency mode string based on the bus frequency */
+const char *i2c_freq_mode_string(u32 bus_freq_hz);
+
 /*
  * The master routines are the ones normally used to transmit data to devices
  * on a bus (or read from them). Apart from two basic transfer functions to