The driver has an OF match table, still, it uses an ID lookup table for
retrieving match data. Currently, the driver is working on the
assumption that an I2C device registered via OF will always match a
legacy I2C device ID. The correct approach is to have an OF device ID
table using i2c_get_match_data() if the devices are registered via OF/ID.
Unify the OF/ID table by using max_freq as match data instead of
enum si544_speed_grade and replace the ID lookup table for
the match data by i2c_get_match_data(). This allows to simplify both
probe() and is_valid_frequency().
Drop enum si544_speed_grade as there is no user.
While at it, remove the trailing comma in the terminator entry for the OF
table making code robust against (theoretical) misrebases or other similar
things where the new entry goes _after_ the termination without the
compiler noticing.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20230909155418.24426-1-biju.das.jz@bp.renesas.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
The Si544 supports changing frequencies "on the fly" when the change is
less than 950 ppm from the current center frequency. The driver now
uses the small adjustment routine for implementing this.
Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This adds prepare/unprepare/is_prepared functionality to the drivers for
the SI544 and SI514 chips, allowing the clock output to be disabled when
the clock is not in use.
Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
The si544 driver had a rounding problem that using the result of clk_round_rate
may set the clock to yet another rate, for example:
clk_round_rate(195000000) = 194999999
clk_round_rate(194999999) = 194999998
Clients would expect that after clk_set_rate(clk, freq2=clk_round_rate(clk, freq)) the
chip will be running at exactly freq2.
The problem was in the calculation of the feedback divider, it was always rounded
down instead of to the nearest possible VCO value.
After this change, the following holds true for any supported frequency:
actual_freq = clk_round_rate(clk, freq);
clk_set_rate(clk, actual_freq);
clk_round_rate(clk, actual_freq) == actual_freq && clk_get_rate(clk) == actual_freq
Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Fixes: 953cc3e811 ("clk: Add driver for the si544 clock generator chip")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This patch adds the driver and devicetree documentation for the
Silicon Labs SI544 clock generator chip. This is an I2C controlled
oscillator capable of generating clock signals ranging from 200kHz
to 1500MHz.
Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
[sboyd: assign max_freq to 0 in is_valid_frequency() to squelch warning]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
