[PATCH v3 3/9] i2c: add support for filter-width-ns optional property

Eugen.Hristev
2019-07-09T13:20:13Z

This optional timing property specifies the width of the spikes on the i2c
lines (in ns) that can be filtered out by built-in analog or digital filters
which are embedded in some i2c controllers.
Include it in the timings structure and read it as integer property.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
drivers/i2c/i2c-core-base.c | 2 ++
include/linux/i2c.h | 2 ++
2 files changed, 4 insertions(+)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 9e43508..73d1c62 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -1658,6 +1658,8 @@ void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_de
t->sda_fall_ns = t->scl_fall_ns;

device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
+
+ device_property_read_u32(dev, "i2c-filter-width-ns", &t->filter_width_ns);
}
EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 1308126..dfb6525 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -563,6 +563,7 @@ struct i2c_lock_operations {
* @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
* @sda_hold_ns: time IP core additionally needs to hold SDA in ns
+ * @filter_width_ns: width in ns of spikes on i2c lines that the IP core can filter out
*/
struct i2c_timings {
u32 bus_freq_hz;
@@ -571,6 +572,7 @@ struct i2c_timings {
u32 scl_int_delay_ns;
u32 sda_fall_ns;
u32 sda_hold_ns;
+ u32 filter_width_ns;
};

/**
--
2.7.4