[PATCH v2 08/18] clk: at91: sckc: register slow_rc with accuracy option

From: Claudiu Beznea
Date: Wed Jul 22 2020 - 03:39:05 EST


Chapter 57.7.5 of SAM9X60 datasheet specifies that the maximum drift of
this oscillator is +- 3KHz. Use that value and the formula at [1]
or the calculator at [2] to compute the PPB value.

[1] https://www.everythingrf.com/rf-calculators/ppm-to-hz-calculator
[2] https://www.changpuak.ch/electronics/ppm_to_Hz_converter.php

Fixes: 04bcc4275e601 ("clk: at91: sckc: add support for SAM9X60")
Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
---
drivers/clk/at91/sckc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/at91/sckc.c b/drivers/clk/at91/sckc.c
index 15dc4cd86d76..2d65770d8665 100644
--- a/drivers/clk/at91/sckc.c
+++ b/drivers/clk/at91/sckc.c
@@ -471,8 +471,9 @@ static void __init of_sam9x60_sckc_setup(struct device_node *np)
if (!regbase)
return;

- slow_rc = clk_hw_register_fixed_rate(NULL, parent_names[0], NULL, 0,
- 32768);
+ slow_rc = clk_hw_register_fixed_rate_with_accuracy(NULL, parent_names[0],
+ NULL, 0, 32768,
+ 93750000);
if (IS_ERR(slow_rc))
return;

--
2.7.4