From: boris.brezillon@free-electrons•com (Boris BREZILLON)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 1/7] mfd: add atmel-hlcdc driver
Date: Sun, 15 Jun 2014 16:48:58 +0200 [thread overview]
Message-ID: <539DB25A.4000201@free-electrons.com> (raw)
In-Reply-To: <539D5F24.1020304@traphandler.com>
Hello JJ,
On 15/06/2014 10:53, Jean-Jacques Hiblot wrote:
> On 06/09/2014 06:04 PM, Boris BREZILLON wrote:
>> The HLCDC IP available on some Atmel SoCs (i.e. at91sam9n12, at91sam9x5
>> family or sama5d3 family) exposes 2 subdevices:
>> - a display controller (controlled by a DRM driver)
>> - a PWM chip
>>
>> Add support for the MFD device which will just retrieve HLCDC clocks and
>> create a regmap so that subdevices can access the HLCDC register range
>> concurrently.
>>
>> Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons•com>
>> ---
>> .../devicetree/bindings/mfd/atmel-hlcdc.txt | 41 ++++++++
>> drivers/mfd/Kconfig | 11 ++
>> drivers/mfd/Makefile | 1 +
[...]
>> + memset(&config, 0, sizeof(config));
>> + config.reg_bits = 32;
>> + config.val_bits = 32;
>> + config.reg_stride = 4;
>> + config.max_register = (resource_size(res) / 4) - 1;
>> + hlcdc->regmap = devm_regmap_init_mmio_clk(dev, "periph_clk", regs,
>> + &config);
> I don't think it's necessary to use "periph_clk" here. This clock will
> always be running because the HLCDC needs it to work (it's not just an
> interface clock). In the end it's just some extra work for each register
> access.
Yes, I thought about removing this clk from regmap registration too (for
the exact same reason: avoiding extra enable/disable work when accessing
registers), but ATM I do not prepare/enable periph_clk in the hlcdc-pwm
driver, this means the regmap won't work until the hlcdc-dc driver has
probed the display controller device.
How about preparing/enabling the periph_clk in the MFD device, so that
PWM and Display Controller subdevices won't have to bother about this
clk, and the regmap will work as expected ?
Or, should we just prepare/enable the periph clock in each subdevices ?
Best Regards,
Boris
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
next prev parent reply other threads:[~2014-06-15 14:48 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-09 16:04 [PATCH v2 0/7] drm: add support for Atmel HLCDC Display Controller Boris BREZILLON
2014-06-09 16:04 ` [PATCH v2 1/7] mfd: add atmel-hlcdc driver Boris BREZILLON
2014-06-15 8:53 ` Jean-Jacques Hiblot
2014-06-15 14:48 ` Boris BREZILLON [this message]
2014-06-16 7:46 ` Jean-Jacques Hiblot
2014-06-16 12:50 ` Lee Jones
2014-06-16 13:23 ` Boris BREZILLON
2014-06-16 17:03 ` Lee Jones
2014-06-16 17:09 ` Boris BREZILLON
2014-06-09 16:04 ` [PATCH v2 2/7] pwm: add support for atmel-hlcdc-pwm device Boris BREZILLON
2014-06-13 11:43 ` Alexandre Belloni
2014-06-13 12:17 ` Boris BREZILLON
2014-06-15 9:11 ` Jean-Jacques Hiblot
2014-06-15 14:55 ` Boris BREZILLON
2014-07-04 13:31 ` Boris BREZILLON
2014-06-09 16:04 ` [PATCH v2 3/7] drm: add Atmel HLCDC Display Controller support Boris BREZILLON
[not found] ` <539D6839.1070703@traphandler.com>
2014-06-15 15:00 ` Boris BREZILLON
2014-06-09 16:04 ` [PATCH v2 4/7] ARM: at91/dt: split sama5d3 lcd pin definitions to match RGB mode configs Boris BREZILLON
2014-06-19 7:07 ` Bo Shen
2014-06-19 7:40 ` Boris BREZILLON
2014-06-19 11:42 ` Boris BREZILLON
2014-06-09 16:04 ` [PATCH v2 5/7] ARM: at91/dt: define the HLCDC node available on sama5d3 SoCs Boris BREZILLON
2014-06-09 16:04 ` [PATCH v2 6/7] ARM: at91/dt: add LCD panel description to sama5d3xdm.dtsi Boris BREZILLON
2014-06-09 16:04 ` [PATCH v2 7/7] ARM: at91/dt: enable the LCD panel on sama5d3xek boards Boris BREZILLON
2014-06-19 7:12 ` Bo Shen
2014-06-19 7:54 ` Boris BREZILLON
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