Thread (142 messages) flat view 142 messages, 11 authors, 2017-07-31

Re: [PATCH 12/13] pwm: jz4740: Let the pinctrl driver configure the pins

From: Thierry Reding <hidden>
Date: 2017-01-18 07:29:04
Also in: linux-devicetree, linux-gpio, linux-mips, linux-mmc, linux-pwm, lkml

On Wed, Jan 18, 2017 at 12:14:20AM +0100, Paul Cercueil wrote:
quoted hunk ↗ jump to hunk
Now that the JZ4740 and similar SoCs have a pinctrl driver, we rely on
the pins being properly configured before the driver probes.

One inherent problem of this new approach is that the pinctrl framework
does not allow us to configure each pin on demand, when the various PWM
channels are requested or released. For instance, the PWM channels can
be configured from sysfs, which would require all PWM pins to be configured
properly beforehand for the PWM function, eventually causing conflicts
with other platform or board drivers.

The proper solution here would be to modify the pwm-jz4740 driver to
handle only one PWM channel, and create an instance of this driver
for each one of the 8 PWM channels. Then, it could use the pinctrl
framework to dynamically configure the PWM pin it controls.

Until this can be done, the only jz4740 board supported upstream
(Qi lb60) could configure all of its connected PWM pins in PWM function
mode, if those are not used by other drivers nor by GPIOs on the
board.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 drivers/pwm/pwm-jz4740.c | 29 -----------------------------
 1 file changed, 29 deletions(-)
diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
index 76d13150283f..a75ff3622450 100644
--- a/drivers/pwm/pwm-jz4740.c
+++ b/drivers/pwm/pwm-jz4740.c
@@ -21,22 +21,10 @@
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 
-#include <asm/mach-jz4740/gpio.h>
What about the linux/gpio.h header? It seems to me like that would be no
longer needed after this patch either.

Other than that this looks like the patch I'd expect if the pinmux was
configured statically, based on board design.

Thierry

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