[PATCH v6 2/5] i2c: core: add api to provide frequency mode strings

[Yicong Yang]

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@xxxxxxxxxxxxxxx>
Reviewed-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
---
 include/linux/i2c.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 10bd0b0..7268180 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -47,6 +47,26 @@ typedef int (*i2c_slave_cb_t)(struct i2c_client *client,
 #define I2C_MAX_HIGH_SPEED_MODE_FREQ	3400000
 #define I2C_MAX_ULTRA_FAST_MODE_FREQ	5000000
 
+static inline 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";
+	}
+}
+
 struct module;
 struct property_entry;
 
-- 
2.8.1