Commit Graph

7 Commits

Author SHA1 Message Date
Jerome Brunet fd7b2be8cb pwm: meson: Improve PWM calculation precision
When using input clocks with high rates, such as clk81 (166MHz), the
fin_ns = NSEC_PER_SEC / fin_freq can introduce a significant error.

Ex: fin_freq = 166666667, NSEC_PER_SEC = 1000000000
    fin_ns = 5,9999999

which is, of course, rounded down to 5. This introduces an error of ~20%
on the period requested from the PWM.

This patch uses ps instead of ns (and 64 bit integers) to perform the
calculation. This should give a good enough precision.

Fixes: 211ed63075 ("pwm: Add support for Meson PWM Controller")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

squash! pwm: meson: Improve pwm calculation precision
2017-07-06 17:15:43 +02:00
Jerome Brunet d396b20a1e pwm: meson: Add compatible for the gxbb ao PWMs
On the gxbb (and gxl) family, the PWMs of the AO domain require a
specific compatible because the possible input clocks are different
from the EE PWMs input clocks.

Since the number of possible input clocks is also different, the
'num_parents' field is added to all the Meson PWM data.

Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-07-06 09:05:22 +02:00
Linus Torvalds 57d64e6f5f pwm: Changes for v4.10-rc1
This is a very tiny pull request, with just a new driver for HiSilicon
 BVT SoCs and a cleanup for the Amlogic Meson driver.
 
 There are other patches on the list, but my timing was really bad this
 time and I ended up not having the time to look at them in enough detail
 to be comfortable merging them.
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Merge tag 'pwm/for-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This is a very tiny pull request, with just a new driver for HiSilicon
  BVT SoCs and a cleanup for the Amlogic Meson driver.

  There are other patches on the list, but my timing was really bad this
  time and I ended up not having the time to look at them in enough
  detail to be comfortable merging them"

* tag 'pwm/for-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  pwm: Add PWM driver for HiSilicon BVT SOCs
  pwm: meson: Remove unneeded platform MODULE_ALIAS
2016-12-15 11:45:13 -08:00
Javier Martinez Canillas 58d5b69363 pwm: meson: Remove unneeded platform MODULE_ALIAS
The Amlogic Meson is a DT-only platform, which means the devices are
registered via OF and not using the legacy platform devices support.

So there's no need to have a MODULE_ALIAS("platform:meson-pwm") since
the reported uevent MODALIAS to user-space will always be the OF one.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-10-21 09:12:41 +02:00
Axel Lin c699995663 pwm: meson: Add missing spin_lock_init()
The driver uses the spin_lock but does not initialize it. Fix it.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-10-21 09:10:11 +02:00
Arnd Bergmann 2fbc487df6 pwm: meson: Handle unknown ID values
When building with -Wmaybe-uninitialized, we get a couple of harmless
warnings about three functions in this new driver that don't look
safe to the compiler:

drivers/pwm/pwm-meson.c: In function 'meson_pwm_get_state':
drivers/pwm/pwm-meson.c:355:26: error: 'mask' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/pwm/pwm-meson.c: In function 'meson_pwm_disable':
drivers/pwm/pwm-meson.c:263:13: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/pwm/pwm-meson.c: In function 'meson_pwm_apply':
drivers/pwm/pwm-meson.c:231:13: error: 'clk_shift' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/pwm/pwm-meson.c:231:36: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/pwm/pwm-meson.c:231:24: error: 'clk_enable' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Specifically, if we have a device with an ID other than 0 or 1,
this would result in undefined behavior. This is currently not
possible, but the compiler cannot be expected to know this.

This patch adds a 'default' clause to let the compiler know
what to do instead, which shuts up the warning and makes the
code slightly more resiliant in case it gets extended to other
identifiers.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-09-08 10:58:33 +02:00
Neil Armstrong 211ed63075 pwm: Add support for Meson PWM Controller
Add support for the PWM controller found in the Amlogic SoCs. This
driver supports the Meson8b and GXBB SoCs.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-09-08 10:55:00 +02:00