linux/drivers/pwm
Sascha Hauer 9fb27fac39 pwm: imx: Remove ipg clock and enable per clock when required
The use of the ipg clock was introduced with commit 7b27c160c6 ("pwm:
i.MX: fix clock lookup"). In the commit message it was claimed that the
ipg clock is enabled for register accesses. This is true for the
->config() callback, but not for the ->set_enable() callback. Given that
the ipg clock is not consistently enabled for all register accesses we
can assume that either it is not required at all or that the current
code does not work. Remove the ipg clock code for now so that it's no
longer in the way of refactoring the driver.

On the other hand, the i.MX 7 IP requires the peripheral clock to be
enabled before accessing its registers. Since ->config() can be called
when the PWM is disabled (in which case, the peripheral clock is also
disabled), we need to surround the imx->config() with
clk_prepare_enable(per_clk)/clk_disable_unprepare(per_clk) calls.

Note that the driver was working fine for the i.MX 7 IP so far because
the ipg and peripheral clock use the same hardware clock gate, which
guaranteed peripheral clock activation even when ->config() was called
when the PWM was disabled.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Tested-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-01-30 09:12:18 +01:00
..
core.c pwm: Unexport children before chip removal 2016-09-05 16:45:39 +02:00
Kconfig pwm: bcm-iproc: Update dependencies for compile-test 2017-01-19 00:38:17 +01:00
Makefile pwm: Add PWM driver for HiSilicon BVT SOCs 2016-11-29 16:50:12 +01:00
pwm-ab8500.c pwm: drop owner assignment from platform_drivers 2014-10-20 16:21:28 +02:00
pwm-atmel-hlcdc.c pwm: atmel-hlcdc: Fix default PWM polarity 2016-06-14 10:51:45 +02:00
pwm-atmel-tcb.c misc: atmel_tclib: get and use slow clock 2015-10-06 12:33:14 +02:00
pwm-atmel.c pwm: atmel: Use of_device_get_match_data() 2016-07-11 12:49:36 +02:00
pwm-bcm2835.c pwm: bcm2835: Fix email address specification 2015-12-16 16:45:32 +01:00
pwm-bcm-iproc.c pwm: Add support for Broadcom iProc PWM controller 2016-07-11 12:49:25 +02:00
pwm-bcm-kona.c pwm: kona: Modify settings application sequence 2015-08-17 16:19:41 +02:00
pwm-berlin.c pwm: berlin: Add suspend/resume support 2016-09-06 10:48:52 +02:00
pwm-bfin.c pwm: constify pwm_ops structures 2017-01-19 00:38:17 +01:00
pwm-brcmstb.c pwm: brcmstb: Fix check of devm_ioremap_resource() return code 2016-03-23 17:11:45 +01:00
pwm-clps711x.c pwm: clps711x: Changing the compatibility string to match with the smallest supported chip 2016-07-06 17:38:17 +02:00
pwm-crc.c pwm: Use pwm_get/set_xxx() helpers where appropriate 2016-05-17 14:44:59 +02:00
pwm-cros-ec.c pwm: cros-ec: Add __packed to prevent padding 2016-09-06 10:48:54 +02:00
pwm-ep93xx.c pwm: Add the pwm_is_enabled() helper 2015-07-20 09:46:06 +02:00
pwm-fsl-ftm.c pwm: fsl-ftm: Use flat regmap cache 2016-04-14 16:54:00 +02:00
pwm-hibvt.c pwm: Add PWM driver for HiSilicon BVT SOCs 2016-11-29 16:50:12 +01:00
pwm-img.c pwm: img: Test clock rate to avoid division by 0 2016-03-23 17:11:02 +01:00
pwm-imx.c pwm: imx: Remove ipg clock and enable per clock when required 2017-01-30 09:12:18 +01:00
pwm-jz4740.c pwm: drop owner assignment from platform_drivers 2014-10-20 16:21:28 +02:00
pwm-lp3943.c pwm: drop owner assignment from platform_drivers 2014-10-20 16:21:28 +02:00
pwm-lpc18xx-sct.c pwm: lpc-18xx: use pwm_set_chip_data 2016-09-08 10:55:05 +02:00
pwm-lpc32xx.c pwm: lpc32xx: Set PWM_PIN_LEVEL bit to default value 2016-07-11 12:49:29 +02:00
pwm-lpss-pci.c pwm: lpss: Add Intel Gemini Lake PCI ID 2017-01-30 08:17:18 +01:00
pwm-lpss-platform.c pwm: lpss: Do not export board infos for different PWM types 2017-01-30 08:16:55 +01:00
pwm-lpss.c pwm: lpss: Do not export board infos for different PWM types 2017-01-30 08:16:55 +01:00
pwm-lpss.h pwm: lpss: Do not export board infos for different PWM types 2017-01-30 08:16:55 +01:00
pwm-meson.c pwm: Changes for v4.10-rc1 2016-12-15 11:45:13 -08:00
pwm-mtk-disp.c pwm: Add MediaTek MT2701 display PWM driver support 2016-09-06 10:48:53 +02:00
pwm-mxs.c pwm: Add the pwm_is_enabled() helper 2015-07-20 09:46:06 +02:00
pwm-omap-dmtimer.c pwm: omap-dmtimer: Allow for setting dmtimer clock source 2016-06-29 21:54:00 -07:00
pwm-pca9685.c pwm: pca9685: Fix period change with same duty cycle 2017-01-20 07:43:22 +01:00
pwm-puv3.c pwm: drop owner assignment from platform_drivers 2014-10-20 16:21:28 +02:00
pwm-pxa.c pwm: constify pwm_ops structures 2017-01-19 00:38:17 +01:00
pwm-rcar.c pwm: rcar: Make use of pwm_is_enabled() 2016-05-17 14:44:57 +02:00
pwm-renesas-tpu.c pwm: Add the pwm_is_enabled() helper 2015-07-20 09:46:06 +02:00
pwm-rockchip.c pwm: rockchip: Add support for atomic update 2016-07-11 12:49:28 +02:00
pwm-samsung.c pwm: samsung: Fix to use lowest div for large enough modulation bits 2016-09-06 10:48:55 +02:00
pwm-spear.c pwm: drop owner assignment from platform_drivers 2014-10-20 16:21:28 +02:00
pwm-sti.c pwm: sti: Take the opportunity to conduct a little house keeping 2016-09-08 10:55:12 +02:00
pwm-stmpe.c pwm: Add a driver for the STMPE PWM 2016-07-11 12:49:29 +02:00
pwm-sun4i.c pwm: sunxi: Add H3 support 2016-09-08 10:55:05 +02:00
pwm-tegra.c pwm: tegra: Add support for Tegra186 2016-07-11 12:49:34 +02:00
pwm-tiecap.c pwm: pwm-ti*: Remove support for local clock gating 2016-07-11 12:07:18 +02:00
pwm-tiehrpwm.c pwm: pwm-ti*: Remove support for local clock gating 2016-07-11 12:07:18 +02:00
pwm-tipwmss.c pwm: pwm-tipwmss: Remove all runtime PM gets/puts 2016-09-06 10:48:54 +02:00
pwm-twl-led.c pwm: twl-led: Include linux/of.h header 2013-10-08 15:45:44 +02:00
pwm-twl.c pwm: twl: Reliably disable TWL6030 PWMs 2016-09-05 07:13:47 +02:00
pwm-vt8500.c pwm: constify pwm_ops structures 2017-01-19 00:38:17 +01:00
sysfs.c pwm: Fix device reference leak 2016-11-29 16:43:24 +01:00