diff options
| author | Hugo Villeneuve <hvilleneuve@dimonoff.com> | 2026-04-17 10:53:37 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-05-11 17:20:18 +0200 |
| commit | ebd57bda9df6234d93e05dfe2fd250c6535ca3bb (patch) | |
| tree | 40b9e1d722a14075849f3839adaa586085949376 /drivers | |
| parent | 922cc077b248a786a93339e7b76bc21ed8575ac7 (diff) | |
serial: max310x: add comments for PLL limits
Add comments to help clarify the provenance of the various hardcoded values
used in computing the ref clk.
Assisted-by: Gemini:Pro
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20260417-max310x-2-v1-10-b424e105ecac@dimonoff.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/serial/max310x.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index 748306d1a932..9f423b3b4201 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -585,6 +585,23 @@ static u8 max310x_pll_mult_to_id(u8 pll_mult) } } +/* + * From table 7 in datasheet: PLLFactor Selector Guide + * + * +-----------+----------------+-------------------+-------------------+ + * | PLLFactor | MULTIPLICATION | fPLLIN | fREF | + * | (1 & 0) | FACTOR +---------+---------+---------+---------+ + * | | | MIN | MAX | MIN | MAX | + * +-----------+----------------+---------+---------+---------+---------+ + * | 0 | 6 | 500kHz | 800kHz | 3MHz | 4.8MHz | + * +-----------+----------------+---------+---------+---------+---------+ + * | 1 | 48 | 850kHz | 1.2MHz | 40.8MHz | 56MHz | + * +-----------+----------------+---------+---------+---------+---------+ + * | 2 | 96 | 425kHz | 1MHz | 40.8MHz | 96MHz | + * +-----------+----------------+---------+---------+---------+---------+ + * | 3 | 144 | 390kHz | 667kHz | 56MHz | 96MHz | + * +-----------+----------------+---------+---------+---------+---------+ + */ static int max310x_set_ref_clk(struct device *dev, struct max310x_port *s, unsigned int freq, unsigned int *fref, bool xtal) { |