Re: [PATCH v3] ASoC: tas2552: Support TI TAS2552 Amplifier

[Dan Murphy <dmurphy@ti.com>]

Felipe

As always great feedback thanks!!!

On 07/02/2014 10:43 AM, Felipe Balbi wrote:
> Hi,
>
> On Wed, Jul 02, 2014 at 10:30:25AM -0500, Dan Murphy wrote:
>> On 07/02/2014 10:03 AM, Felipe Balbi wrote:
>>> Hi,
>>>
>>> On Wed, Jul 02, 2014 at 09:53:10AM -0500, Dan Murphy wrote:
>>>> Felipe
>>>> Thanks for the review
>>>>
>>>> On 07/02/2014 09:10 AM, Felipe Balbi wrote:
>>>>> Hi,
>>>>>
>>>>> On Wed, Jul 02, 2014 at 08:30:52AM -0500, Dan Murphy wrote:
>>>>>> Support the TI TAS2552 Class D amplifier.
>>>>>>
>>>>>> The TAS2552 is a high efficiency Class-D audio
>>>>>> power amplifier with advanced battery current
>>>>>> management and an integrated Class-G boost
>>>>>> The device constantly measures the
>>>>>> current and voltage across the load and provides a
>>>>>> digital stream of this information.
>>>>>>
>>>>>> Signed-off-by: Dan Murphy <dmurphy@ti.com>
>>>>>> ---
>>>>>>
>>>>>> v3 - Updated bindings doc per comments, rearranged probe pdata vs 
>>>>>> np check - https://patchwork.kernel.org/patch/4453481/
>>>>>>
>>>>>>  .../devicetree/bindings/sound/tas2552.txt          |   22 +
>>>>>>  include/sound/tas2552-plat.h                       |   25 ++
>>>>>>  sound/soc/codecs/Kconfig                           |    5 +
>>>>>>  sound/soc/codecs/Makefile                          |    2 +
>>>>>>  sound/soc/codecs/tas2552.c                         |  463 ++++++++++++++++++++
>>>>>>  sound/soc/codecs/tas2552.h                         |   75 ++++
>>>>>>  6 files changed, 592 insertions(+)
>>>>>>  create mode 100644 Documentation/devicetree/bindings/sound/tas2552.txt
>>>>>>  create mode 100644 include/sound/tas2552-plat.h
>>>>>>  create mode 100644 sound/soc/codecs/tas2552.c
>>>>>>  create mode 100644 sound/soc/codecs/tas2552.h
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/sound/tas2552.txt b/Documentation/devicetree/bindings/sound/tas2552.txt
>>>>>> new file mode 100644
>>>>>> index 0000000..ada8fd4
>>>>>> --- /dev/null
>>>>>> +++ b/Documentation/devicetree/bindings/sound/tas2552.txt
>>>>>> @@ -0,0 +1,22 @@
>>>>>> +Texas Instruments - tas2552 Codec module
>>>>>> +
>>>>>> +The tas2552 serial control bus communicates through I2C protocols
>>>>>> +
>>>>>> +Required properties:
>>>>>> +
>>>>>> +- compatible - One of:
>>>>>> +    "ti,tas2552" - TAS2552
>>>>>> +
>>>>>> +- reg -  I2C slave address
>>>>>> +
>>>>>> +Optional properties:
>>>>>> +
>>>>>> +- power-gpio - gpio pin to enable/disable the device
>>>>>> +
>>>>>> +Example:
>>>>>> +
>>>>>> +tas2552: tas2552@41 {
>>>>>> +	compatible = "ti,tas2552";
>>>>>> +	reg = <0x41>;
>>>>>> +	enable-gpio = <&gpio4 2 GPIO_ACTIVE_HIGH>;
>>>>> you probably want to add:
>>>>>
>>>>> 	pvdd-supply = <&pvdd>;
>>>>> 	vbat-supply = <&vbat>;
>>>>> 	avdd-supply = <&avdd>;
>>>>> 	iovdd-supply = <&iovdd>;
>>>>>
>>>>> that way you can make sure to switch your regulators on from the driver.
>>>>> Since they must be all on, you can just grab them all with
>>>>> regulator_bulk_get() and enable them all with regulator_bulk_enable().
>>>> I could add this but I don't have a use case for this so I did not add
>>>> the code.
>>> actually, you do. Right now you have a device which is powered by
>>> several different sources (fixed or not).
>> Does the regulator_enable *gaurantee* that the supplies will be turned on in
>> the following order?
>>
>> 1. VBAT,
>> 2. IOVDD,
>> 3. AVDD.
> you can always regulator_enable() each one in the order you want.

Will add this then.

>
>>>> The supplies I used were always-on so adding the regulators was not
>>>> testable in this patchset.
>>> it _is_ testable. regulator_get()/regulator_enable() still works on
>>> fixed regulators.
>> I did not say i used fixed regulators.  I indicated that the regulators
>> were always-on.  So regulator_enable/disable would have no affect.  right?
>>
>> I mean you cannot turn off vbat right?
> It depends. If you're sharing VBAT with the board's power source, then
> yeah, you can't disable it. You would still see
> regulator_enable()/regulator_disable() being called, which serves as
> unit testing.
>
> And VBAT, *would* be modeled as a fixed regulator, so all the code paths
> are tested, it's just that there's no gpio (or whatever) to be toggled
> for VBAT.
>
>>>>>> @@ -325,3 +326,4 @@ obj-$(CONFIG_SND_SOC_WM_HUBS)	+= snd-soc-wm-hubs.o
>>>>>>  # Amp
>>>>>>  obj-$(CONFIG_SND_SOC_MAX9877)	+= snd-soc-max9877.o
>>>>>>  obj-$(CONFIG_SND_SOC_TPA6130A2)	+= snd-soc-tpa6130a2.o
>>>>>> +obj-$(CONFIG_SND_SOC_TAS2552)	+= snd-soc-tas2552.o
>>>>>> diff --git a/sound/soc/codecs/tas2552.c b/sound/soc/codecs/tas2552.c
>>>>>> new file mode 100644
>>>>>> index 0000000..79b8212
>>>>>> --- /dev/null
>>>>>> +++ b/sound/soc/codecs/tas2552.c
>>>>>> @@ -0,0 +1,463 @@
>>>>>> +/*
>>>>>> + * ALSA SoC Texas Instruments TAS2552 Mono Audio Amplifier
>>>>>> + *
>>>>>> + * Copyright (C) 2014 Texas Instruments Inc.
>>>>>> + *
>>>>>> + * Author: Dan Murphy <dmurphy@ti.com>
>>>>>> + *
>>>>>> + * This program is free software; you can redistribute it and/or
>>>>>> + * modify it under the terms of the GNU General Public License
>>>>>> + * version 2 as published by the Free Software Foundation.
>>>>>> + *
>>>>>> + * This program is distributed in the hope that it will be useful, but
>>>>>> + * WITHOUT ANY WARRANTY; without even the implied warranty of
>>>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>>>>>> + * General Public License for more details.
>>>>>> + */
>>>>>> +
>>>>>> +#include <linux/module.h>
>>>>>> +#include <linux/errno.h>
>>>>>> +#include <linux/device.h>
>>>>>> +#include <linux/i2c.h>
>>>>>> +#include <linux/gpio.h>
>>>>>> +#include <linux/of_gpio.h>
>>>>>> +#include <linux/regmap.h>
>>>>>> +#include <linux/slab.h>
>>>>>> +
>>>>>> +#include <sound/pcm.h>
>>>>>> +#include <sound/pcm_params.h>
>>>>>> +#include <sound/soc.h>
>>>>>> +#include <sound/soc-dapm.h>
>>>>>> +#include <sound/tlv.h>
>>>>>> +#include <sound/tas2552-plat.h>
>>>>>> +
>>>>>> +#include "tas2552.h"
>>>>>> +
>>>>>> +static struct reg_default tas2552_reg_defs[] = {
>>>>>> +	{TAS2552_CFG_1, 0x16},
>>>>>> +	{TAS2552_CFG_3, 0x5E},
>>>>>> +	{TAS2552_DOUT, 0x00},
>>>>>> +	{TAS2552_OUTPUT_DATA, 0xC8},
>>>>>> +	{TAS2552_PDM_CFG, 0x02},
>>>>>> +	{TAS2552_PGA_GAIN, 0x10},
>>>>>> +	{TAS2552_BOOST_PT_CTRL, 0x0F},
>>>>>> +	{TAS2552_LIMIT_LVL_CTRL, 0x0C},
>>>>>> +	{TAS2552_LIMIT_RATE_HYS, 0x20},
>>>>>> +	{TAS2552_CFG_2, 0xEA},
>>>>>> +	{TAS2552_SER_CTRL_1, 0x00},
>>>>>> +	{TAS2552_SER_CTRL_2, 0x00},
>>>>>> +	{TAS2552_PLL_CTRL_1, 0x10},
>>>>>> +	{TAS2552_PLL_CTRL_2, 0x00},
>>>>>> +	{TAS2552_PLL_CTRL_3, 0x00},
>>>>>> +	{TAS2552_BTIP, 0x8f},
>>>>>> +	{TAS2552_BTS_CTRL, 0x80},
>>>>>> +	{TAS2552_LIMIT_RELEASE, 0x05},
>>>>>> +	{TAS2552_LIMIT_INT_COUNT, 0x00},
>>>>>> +	{TAS2552_EDGE_RATE_CTRL, 0x40},
>>>>>> +	{TAS2552_VBAT_DATA, 0x00},
>>>>>> +};
>>>>>> +
>>>>>> +struct tas2552_data {
>>>>>> +	struct mutex mutex;
>>>>>> +	struct snd_soc_codec *codec;
>>>>>> +	struct regmap *regmap;
>>>>>> +	struct i2c_client *tas2552_client;
>>>>>> +	unsigned char regs[TAS2552_VBAT_DATA];
>>>>>> +	int power_gpio;
>>>>>> +	u8 power_state:1;
>>>>>> +};
>>>>>> +
>>>>>> +static int tas2552_power(struct tas2552_data *data, u8 power)
>>>>>> +{
>>>>>> +	int	ret = 0;
>>>>>> +
>>>>>> +	BUG_ON(data->tas2552_client == NULL);
>>>>> don't hang the entire machine because of a bug on the amplifier driver,
>>>>> WARN() should be enough, followed by the return of an error code.
>>>>>
>>>>> In fact, is this really necessary ? It would be a simple bug on the
>>>>> driver to fix.
>>>> Yeah I can remove this.  I was following an older example.
>>>>
>>>>>> +
>>>>>> +	mutex_lock(&data->mutex);
>>>>>> +	if (power == data->power_state)
>>>>> Same here. Is this really necessary ? It's simple to guarantee this case
>>>>> won't happen in code.
>>>> Yes this LOC is necessary.  It is checking the current state of the tas2552.
>>> heh, the point is that all your calls to this function can be balanced
>>> easily, so this check becomes pointless, as it will never be true.
>> I will remove it.
>>
>>>>>> +		goto exit;
>>>>>> +
>>>>>> +	if (power) {
>>>>>> +		if (data->power_gpio >= 0)
>>>>>> +			gpio_set_value(data->power_gpio, 1);
>>>>>> +
>>>>>> +		data->power_state = 1;
>>>>>> +	} else {
>>>>>> +		if (data->power_gpio >= 0)
>>>>>> +			gpio_set_value(data->power_gpio, 0);
>>>>>> +
>>>>>> +		data->power_state = 0;
>>>>>> +	}
>>>>>> +
>>>>>> +exit:
>>>>>> +	mutex_unlock(&data->mutex);
>>>>>> +	return ret;
>>>>>> +}
>>>>>> +
>>>>>> +static void tas2552_sw_shutdown(struct tas2552_data *tas_data, int sw_shutdown)
>>>>>> +{
>>>>>> +	u8 cfg1_reg = 0x0;
>>>>>> +
>>>>>> +	if (sw_shutdown)
>>>>>> +		cfg1_reg |= (sw_shutdown << 1);
>>>>> this line is dangerous. You're using a 32-bit variable to write a single
>>>>> bit on cfg1 register. What if user passes 0xff on sw_shutdown ?
>>>>>
>>>>> I think a better approach would be to:
>>>>>
>>>>> a) first of all, move this sw_shutdown function to
>>>>> runtime_suspend/runtime_resume.
>>>> Yeah that is not the intent of this API.  This API is called when the ALSA layer
>>>> opens/closes the device.  It is not governed by pm calls.
>>> and PM calls are exactly for that. You start with a powered off device,
>>> then when user wants to use it, you power it up. This is exactly what's
>>> you're doing here.
>> I will look into it.
>>
>> But I am not convinced I need these calls yet.
> what your shutdown function is basically a private runtime_pm
> implementation. Look at your usage of it:
>
> 	shutdown(0);
> 	do_something_magical();
> 	shutdown(1);
>
> The translation to:
>
> 	pm_runtime_get_sync();
> 	do_something_magical();
> 	pm_runtime_put_sync();
>
> is really straight forward. You can even move the GPIO enable to
> runtime_resume() and this shutdown(1) to runtime_idle so that it would
> look like:
>
> static int tas2552_runtime_resume(struct device *dev)
> {
> 	struct tas2552_data *tas = dev_get_drvdata(dev);
> 	u8 reg;
>
> 	gpio_set_value(tas->enable_gpio, 1);
> 	reg |= TAS2552_SWS;
> 	snd_soc_update_bits(tas_data->codec, TAS2552_CFG_1,
> 			TAS2552_SWS_MASK, reg);
>
> 	return 0;
> }
>
> static int tas2552_runtime_suspend(struct device *dev)
> {
> 	struct tas2552_data *tas = dev_get_drvdata(dev);
>
> 	gpio_set_value(tas->enable_gpio, 0);
>
> 	return 0;
> }
>
> static int tas2552_runtime_idle(struct device *dev)
> {
> 	struct tas2552_data *tas = dev_get_drvdata(dev);
> 	u8 reg;
>
> 	reg &= ~TAS2552_SWS;
> 	snd_soc_update_bits(tas_data->codec, TAS2552_CFG_1,
> 			TAS2552_SWS_MASK, reg);
> }
>
> how to properly use them in this driver and make sure the device is only
> "suspended" on close() is left as an exercise.

SGTM I will see what I can do.

>
>>>>> b) to the check as below:
>>>>>
>>>>> 	if (shutdown)
>>>>> 		cfg1_reg |= TAS2552_SWS;
>>>>> 	else
>>>>> 		cfg1_reg &= ~TAS2552_SWS;
>>>>>
>>>>> then, of course #define TAS2552_SWS (1 << 1) (or BIT(1), even)
>>>> But I will make this change.
>>>>
>>>>>> +	else
>>>>>> +		cfg1_reg &= ~TAS2552_SWS_MASK;
>>>>>> +
>>>>>> +	snd_soc_update_bits(tas_data->codec, TAS2552_CFG_1,
>>>>>> +						 TAS2552_SWS_MASK, cfg1_reg);
>>>>>> +}
>>>>>> +
>>>>>> +static void tas2552_init(struct snd_soc_codec *codec)
>>>>>> +{
>>>>>> +	snd_soc_write(codec, TAS2552_CFG_1, 0x16);
>>>>>> +	snd_soc_write(codec, TAS2552_CFG_3, 0x5E);
>>>>>> +	snd_soc_write(codec, TAS2552_DOUT, 0x00);
>>>>>> +	snd_soc_write(codec, TAS2552_OUTPUT_DATA, 0xC8);
>>>>>> +	snd_soc_write(codec, TAS2552_PDM_CFG, 0x02);
>>>>>> +	snd_soc_write(codec, TAS2552_PGA_GAIN, 0x10);
>>>>>> +	snd_soc_write(codec, TAS2552_BOOST_PT_CTRL, 0x0F);
>>>>>> +	snd_soc_write(codec, TAS2552_LIMIT_LVL_CTRL, 0x0C);
>>>>>> +	snd_soc_write(codec, TAS2552_LIMIT_RATE_HYS, 0x20);
>>>>>> +	snd_soc_write(codec, TAS2552_CFG_2, 0xEA);
>>>>> what do all these magic constants mean ? Also, lower case hex numbers
>>>>> are usually preferred.
>>>> I will add comments to what the numbers mean and change to lower case
>>> I would rather see proper bit macros and the driver using them.
>> Yeah I started doing that in my initial driver but the bit macros were getting
>> a little obsessive.
>>
>>>>> No battery tracking ?  Any plans to add that at a later date ? It's
>>>>> probably not needed to have functional audio, but might have some use
>>>>> cases where you want it.
>>>> The battery tracking was not the scope of the driver.  We just need to
>>>> get the basic driver in place with audio functional and add the
>>>> battery tracking later.
>>> it's a single bit
>> I will flip the bit for the default.
>>
>> I looked back in my emails and it was the IVsense code I could not develop not
>> the battery checking.
> if you really want to make sure the device *does* track the battery,
> just hook that pin to a lab power supply and slowly dial down the output
> voltage, then look at the gain to see if it is tracking.
>

I could do that.

But that would be testing the HW itself and not really this code.
I would expect to just verify that the bit was flipped and stayed that
way through operation.


-- 
------------------
Dan Murphy