linux-kernel - Re: [PATCH] Input: synaptics-rmi4: Support regulator supplies

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Date:	Thu, 31 Mar 2016 18:47:49 -0700
From:	Andrew Duggan <aduggan@...aptics.com>
To:	Bjorn Andersson <bjorn.andersson@...aro.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:	Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Christopher Heiny <cheiny@...aptics.com>,
	<linux-input@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	Bjorn Andersson <bjorn.andersson@...ymobile.com>
Subject: Re: [PATCH] Input: synaptics-rmi4: Support regulator supplies

On 03/31/2016 12:14 PM, Bjorn Andersson wrote:
> On Thu 31 Mar 11:19 PDT 2016, Dmitry Torokhov wrote:
>
>> Hi Bjorn,
>>
>> On Wed, Mar 30, 2016 at 09:57:29AM -0700, Bjorn Andersson wrote:
>>> From: Bjorn Andersson <bjorn.andersson@...ymobile.com>
>>>
>>> Support the two supplies - vdd and vio - to make it possible to control
>>> power to the Synaptics chip.
>>>
>>> Signed-off-by: Bjorn Andersson <bjorn.andersson@...ymobile.com>
>>> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
>>> ---
>>>   .../devicetree/bindings/input/rmi4/rmi_i2c.txt     |  7 ++++
>>>   drivers/input/rmi4/rmi_i2c.c                       | 45 ++++++++++++++++++++++
>> Would not we need pretty much the same changes for SPI devices? Can this
>> be done in core?
>>
> Yes, I believe it needs the exact same steps.
>
> I did a initial quick hack on v1 of the patchset and back then it was
> possible, when I rebased it a few weeks back I kept ending up in getting
> interrupts with the power off.
>
> Looking at the code this is likely because in the resume paths the IRQ
> is enabled before we jump to rmi_driver_resume(), so putting this in the
> core I ended up calling rmi_process_interrupt_requests() before powering
> up the chip.

Actually, I don't think the irq needs to be enabled before calling 
rmi_driver_resume(). Typically, the functions are just reading and 
writing to registers and do not need to handle interrupts. We could 
probably call to rmi_driver_resume() before enabling the irq. I can 
double check that there are not any exceptions to this.

I have also considered adding a power callback to the core so that the 
transport drivers can set the power independently of suspend and resume. 
One example would be to shut off power to a touchpad if a mouse is 
connected. If we do need to have the irq enabled before calling 
rmi_driver_resume() we could still move regulator support to the core 
and call the power callback from the transport drivers.

Andrew

> I assume it's done this way to allow incoming interrupts while functions
> are being resumed. Andrew, can you comment on this?
>
> Regards,
> Bjorn
>
>> Thanks.
>>
>>>   2 files changed, 52 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/input/rmi4/rmi_i2c.txt b/Documentation/devicetree/bindings/input/rmi4/rmi_i2c.txt
>>> index 95fa715c6046..a8c31f40f816 100644
>>> --- a/Documentation/devicetree/bindings/input/rmi4/rmi_i2c.txt
>>> +++ b/Documentation/devicetree/bindings/input/rmi4/rmi_i2c.txt
>>> @@ -22,6 +22,13 @@ See Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
>>>   - syna,reset-delay-ms: The number of milliseconds to wait after resetting the
>>>   			device.
>>>   
>>> +- vdd-supply: VDD power supply.
>>> +See Documentation/devicetree/bindings/regulator/regulator.txt
>>> +
>>> +- vio-supply: VIO power supply
>>> +See Documentation/devicetree/bindings/regulator/regulator.txt
>>> +
>>> +
>>>   Function Parameters:
>>>   Parameters specific to RMI functions are contained in child nodes of the rmi device
>>>    node. Documentation for the parameters of each function can be found in:
>>> diff --git a/drivers/input/rmi4/rmi_i2c.c b/drivers/input/rmi4/rmi_i2c.c
>>> index a96a326b53bd..a8c794daba04 100644
>>> --- a/drivers/input/rmi4/rmi_i2c.c
>>> +++ b/drivers/input/rmi4/rmi_i2c.c
>>> @@ -11,6 +11,8 @@
>>>   #include <linux/rmi.h>
>>>   #include <linux/irq.h>
>>>   #include <linux/of.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/regulator/consumer.h>
>>>   #include "rmi_driver.h"
>>>   
>>>   #define BUFFER_SIZE_INCREMENT 32
>>> @@ -37,6 +39,8 @@ struct rmi_i2c_xport {
>>>   
>>>   	u8 *tx_buf;
>>>   	size_t tx_buf_size;
>>> +
>>> +	struct regulator_bulk_data supplies[2];
>>>   };
>>>   
>>>   #define RMI_PAGE_SELECT_REGISTER 0xff
>>> @@ -246,6 +250,22 @@ static int rmi_i2c_probe(struct i2c_client *client,
>>>   		return -ENODEV;
>>>   	}
>>>   
>>> +	rmi_i2c->supplies[0].supply = "vdd";
>>> +	rmi_i2c->supplies[1].supply = "vio";
>>> +	retval = devm_regulator_bulk_get(&client->dev,
>>> +					 ARRAY_SIZE(rmi_i2c->supplies),
>>> +					 rmi_i2c->supplies);
>>> +	if (retval < 0)
>>> +		return retval;
>>> +
>>> +	retval = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
>>> +				       rmi_i2c->supplies);
>>> +	if (retval < 0)
>>> +		return retval;
>>> +
>>> +	/* Allow the firmware to get ready */
>>> +	msleep(10);
>>> +
>>>   	rmi_i2c->client = client;
>>>   	mutex_init(&rmi_i2c->page_mutex);
>>>   
>>> @@ -286,6 +306,8 @@ static int rmi_i2c_remove(struct i2c_client *client)
>>>   	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
>>>   
>>>   	rmi_unregister_transport_device(&rmi_i2c->xport);
>>> +	regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
>>> +			       rmi_i2c->supplies);
>>>   
>>>   	return 0;
>>>   }
>>> @@ -308,6 +330,10 @@ static int rmi_i2c_suspend(struct device *dev)
>>>   			dev_warn(dev, "Failed to enable irq for wake: %d\n",
>>>   				ret);
>>>   	}
>>> +
>>> +	regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
>>> +			       rmi_i2c->supplies);
>>> +
>>>   	return ret;
>>>   }
>>>   
>>> @@ -317,6 +343,14 @@ static int rmi_i2c_resume(struct device *dev)
>>>   	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
>>>   	int ret;
>>>   
>>> +	ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
>>> +				    rmi_i2c->supplies);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	/* Allow the firmware to get ready */
>>> +	msleep(10);
>>> +
>>>   	enable_irq(rmi_i2c->irq);
>>>   	if (device_may_wakeup(&client->dev)) {
>>>   		ret = disable_irq_wake(rmi_i2c->irq);
>>> @@ -346,6 +380,9 @@ static int rmi_i2c_runtime_suspend(struct device *dev)
>>>   
>>>   	disable_irq(rmi_i2c->irq);
>>>   
>>> +	regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
>>> +			       rmi_i2c->supplies);
>>> +
>>>   	return 0;
>>>   }
>>>   
>>> @@ -355,6 +392,14 @@ static int rmi_i2c_runtime_resume(struct device *dev)
>>>   	struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
>>>   	int ret;
>>>   
>>> +	ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
>>> +				    rmi_i2c->supplies);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	/* Allow the firmware to get ready */
>>> +	msleep(10);
>>> +
>>>   	enable_irq(rmi_i2c->irq);
>>>   
>>>   	ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev);
>>> -- 
>>> 2.5.0
>>>
>> -- 
>> Dmitry