From: kernel@martin.sperl.org
To: Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
Stephen Warren <swarren@wwwdotorg.org>,
Lee Jones <lee@kernel.org>, Eric Anholt <eric@anholt.net>,
Remi Pommarel <repk@triplefau.lt>,
linux-clk@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org
Cc: Martin Sperl <kernel@martin.sperl.org>
Subject: [PATCH V4 1/7] clk: bcm2835: the minimum clock divider is 2
Date: Fri, 15 Jan 2016 14:21:00 +0000 [thread overview]
Message-ID: <1452867667-2447-2-git-send-email-kernel@martin.sperl.org> (raw)
In-Reply-To: <1452867667-2447-1-git-send-email-kernel@martin.sperl.org>
From: Martin Sperl <kernel@martin.sperl.org>
Testing with different clock divider values has shown
that (at least for the PCM clock) the clock divider
has to be at least 2, otherwise the clock will not
output a signal.
So the clamping has changed from 1 to 2 and comments
about the kind of clamping applied have been added.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
---
drivers/clk/bcm/clk-bcm2835.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 015e687..10e97b7 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1178,7 +1178,11 @@ static u32 bcm2835_clock_choose_div(struct clk_hw *hw,
div &= ~unused_frac_mask;
/* Clamp to the limits. */
- div = max(div, unused_frac_mask + 1);
+
+ /* divider must be >= 2 */
+ div = max_t(u32, div, (2 << CM_DIV_FRAC_BITS));
+
+ /* clamp to max divider allowed */
div = min_t(u32, div, GENMASK(data->int_bits + CM_DIV_FRAC_BITS - 1,
CM_DIV_FRAC_BITS - data->frac_bits));
--
1.7.10.4
next prev parent reply other threads:[~2016-01-15 14:21 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-15 14:20 [PATCH V4 0/7] clk: bcm2835: add clocks and add MASH support kernel
2016-01-15 14:21 ` kernel [this message]
2016-02-01 23:15 ` [PATCH V4 1/7] clk: bcm2835: the minimum clock divider is 2 Eric Anholt
2016-02-02 1:52 ` Eric Anholt
2016-02-08 10:39 ` Martin Sperl
2016-02-08 10:28 ` Martin Sperl
2016-02-13 0:28 ` Eric Anholt
2016-01-15 14:21 ` [PATCH V4 2/7] clk: bcm2835: clamp clock divider to highest integer only kernel
2016-02-01 23:19 ` Eric Anholt
2016-02-08 12:20 ` Martin Sperl
2016-01-15 14:21 ` [PATCH V4 3/7] clk: bcm2835: remove use of BCM2835_CLOCK_COUNT in driver kernel
[not found] ` <1452867667-2447-1-git-send-email-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2016-01-15 14:21 ` [PATCH V4 4/7] clk: bcm2835: enable management of PCM clock kernel-TqfNSX0MhmxHKSADF0wUEw
2016-01-15 14:21 ` [PATCH V4 5/7] clk: bcm2835: add missing 22 HW-clocks kernel
2016-02-02 1:51 ` Eric Anholt
2016-02-08 11:12 ` Martin Sperl
2016-02-17 18:25 ` Martin Sperl
2016-02-17 20:01 ` Stefan Wahren
2016-01-15 14:21 ` [PATCH V4 6/7] clk: bcm2835: enable fractional and mash support kernel
2016-01-15 14:21 ` [PATCH V4 7/7] clk: bcm2835: apply limits on dividers to MASH mode kernel
2016-01-16 9:40 ` [PATCH V4 0/7] clk: bcm2835: add clocks and add MASH support Martin Sperl
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