Thread (32 messages) 32 messages, 3 authors, 2020-07-20

Re: [PATCH 09/19] clk: at91: sckc: register slow_rc with accuracy option

From: <hidden>
Date: 2020-07-15 15:39:39
Also in: linux-clk, lkml


On 15.07.2020 14:24, Claudiu Beznea wrote:
quoted hunk ↗ jump to hunk
Register slow rc with accuracy option.

Fixes: 04bcc4275e601 ("clk: at91: sckc: add support for SAM9X60")
Signed-off-by: Claudiu Beznea <redacted>
---
 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);
I forgot to mention in commit message (I'll do it in v2 once I'll
gather more comments on this series):

Chapter 57.7.5 of SAM9X60 datasheet specifies that the maximum drift of
this oscillator is +- 3KHz. I used 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


Thank you,
Claudiu Beznea
 	if (IS_ERR(slow_rc))
 		return;
 
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