linux-kernel - Re: [PATCH v5 2/3] mfd: lp873x: Add lp873x PMIC support

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Date:	Fri, 5 Aug 2016 10:01:47 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Keerthy <a0393675@...com>
Cc:	Keerthy <j-keerthy@...com>, linus.walleij@...aro.org,
	gnurou@...il.com, linux-omap@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-gpio@...r.kernel.org, broonie@...nel.org, robh+dt@...nel.org,
	tony@...mide.com
Subject: Re: [PATCH v5 2/3] mfd: lp873x: Add lp873x PMIC support

On Fri, 05 Aug 2016, Keerthy wrote:
> On Friday 05 August 2016 01:33 PM, Lee Jones wrote:
> > On Wed, 29 Jun 2016, Keerthy wrote:
> > 
> > > The LP873X chip is a power management IC for Portable Navigation Systems
> > >      and Tablet Computing devices. It contains the following components:
> > > 
> > >       - Regulators.
> > >       - Configurable General Purpose Output Signals(GPO).
> > > 
> > > PMIC interacts with the main processor through i2c. PMIC has
> > > couple of LDOs(Linear Regulators), couple of BUCKs (Step-Down DC-DC
> > > Converter Cores) and GPOs(General Purpose Output Signals).
> > > 
> > > Signed-off-by: Keerthy <j-keerthy@...com>
> > > ---
> > > 
> > > Changes in v4:
> > > 
> > >    * Added Author.
> > >    * Added the mfd_cell for gpio.
> > > 
> > > Changes in v3:
> > > 
> > >    * Reordered the probe code.
> > >    * Fixed Typo in Kconfig description.
> > >    * Removed unused member from struct lp873x.
> > > 
> > >   drivers/mfd/Kconfig        |  14 +++
> > >   drivers/mfd/Makefile       |   2 +
> > >   drivers/mfd/lp873x.c       |  99 +++++++++++++++++
> > >   include/linux/mfd/lp873x.h | 264 +++++++++++++++++++++++++++++++++++++++++++++
> > >   4 files changed, 379 insertions(+)
> > >   create mode 100644 drivers/mfd/lp873x.c
> > >   create mode 100644 include/linux/mfd/lp873x.h
> > > 
> > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > > index 9987d86..e68ac28 100644
> > > --- a/drivers/mfd/Kconfig
> > > +++ b/drivers/mfd/Kconfig
> > > @@ -1221,6 +1221,20 @@ config MFD_TPS65217
> > >   	  This driver can also be built as a module.  If so, the module
> > >   	  will be called tps65217.
> > > 
> > > +config MFD_LP873X
> > 
> > Nicer as MFD_TI_LP873X I think.
> > 
> > > +	tristate "TI LP873X Power Management IC"
> > > +	depends on I2C
> > > +	select MFD_CORE
> > > +	select REGMAP_I2C
> > > +	help
> > > +	  If you say yes here then you get support for the LP873X series of
> > > +	  power management integrated circuits(PMIC).
> > 
> > Power Management Integrated Circuits (PMIC).
> 
> Okay
> 
> > 
> > > +	  These include voltage regulators, Thermal protection, Configurable
> > > +	  general purpose outputs(GPO) that are used in portable devices.
> > 
> > Some here.  Please standardise your capitalisation.
> 
> Okay
> 
> > 
> > > +	  This driver can also be built as a module.  If so, the module
> > > +	  will be called lp873x.
> > > +
> > >   config MFD_TPS65218
> > >   	tristate "TI TPS65218 Power Management chips"
> > >   	depends on I2C
> > > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> > > index 2ba3ba3..7d9b965 100644
> > > --- a/drivers/mfd/Makefile
> > > +++ b/drivers/mfd/Makefile
> > > @@ -22,6 +22,8 @@ obj-$(CONFIG_HTC_EGPIO)		+= htc-egpio.o
> > >   obj-$(CONFIG_HTC_PASIC3)	+= htc-pasic3.o
> > >   obj-$(CONFIG_HTC_I2CPLD)	+= htc-i2cpld.o
> > > 
> > > +obj-$(CONFIG_MFD_LP873X)	+= lp873x.o
> > > +
> > >   obj-$(CONFIG_MFD_DAVINCI_VOICECODEC)	+= davinci_voicecodec.o
> > >   obj-$(CONFIG_MFD_DM355EVM_MSP)	+= dm355evm_msp.o
> > >   obj-$(CONFIG_MFD_TI_AM335X_TSCADC)	+= ti_am335x_tscadc.o
> > > diff --git a/drivers/mfd/lp873x.c b/drivers/mfd/lp873x.c
> > > new file mode 100644
> > > index 0000000..54ed0ce
> > > --- /dev/null
> > > +++ b/drivers/mfd/lp873x.c
> > > @@ -0,0 +1,99 @@
> > > +/*
> > > + * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
> > > + *
> > > + * Author: Keerthy <j-keerthy@...com>
> > > + *
> > > + * This program is free software; you can redistribute it and/or
> > > + * modify it under the terms of the GNU General Public License as
> > > + * published by the Free Software Foundation version 2.
> > > + *
> > > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> > > + * kind, whether express or implied; without even the implied warranty
> > > + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > + * GNU General Public License for more details.
> > > + */
> > > +
> > > +#include <linux/interrupt.h>
> > > +#include <linux/mfd/core.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#include <linux/mfd/lp873x.h>
> > > +
> > > +static const struct regmap_config lp873x_regmap_config = {
> > > +	.reg_bits = 8,
> > > +	.val_bits = 8,
> > > +	.max_register = LP873X_REG_MAX,
> > > +};
> > > +
> > > +static const struct mfd_cell lp873x_cells[] = {
> > > +	{ .name = "lp873x-regulator", },
> > > +	{ .name = "lp873x-gpio", },
> > > +};
> > > +
> > > +static int lp873x_probe(struct i2c_client *client,
> > > +			const struct i2c_device_id *ids)
> > > +{
> > > +	struct lp873x *lp873;
> > > +	int ret;
> > > +	unsigned int otpid;
> > > +
> > > +	lp873 = devm_kzalloc(&client->dev, sizeof(*lp873), GFP_KERNEL);
> > > +	if (!lp873)
> > > +		return -ENOMEM;
> > > +
> > > +	lp873->dev = &client->dev;
> > > +
> > > +	lp873->regmap = devm_regmap_init_i2c(client, &lp873x_regmap_config);
> > > +	if (IS_ERR(lp873->regmap)) {
> > > +		ret = PTR_ERR(lp873->regmap);
> > > +		dev_err(lp873->dev, "Failed to initialize register map: %d\n",
> > > +			ret);
> > 
> > Nit: I'd prefer you break after "->dev,".
> 
> Okay
> 
> > 
> > > +		return ret;
> > > +	}
> > > +
> > > +	mutex_init(&lp873->lp873_lock);
> > 
> > How many locks do you have in 'struct lp873x'?
> > 
> > I suggest that 'lock' will do fine.
> 
> Okay.
> 
> > 
> > > +	ret = regmap_read(lp873->regmap, LP873X_REG_OTP_REV, &otpid);
> > > +	if (ret) {
> > > +		dev_err(lp873->dev, "Failed to read OTP ID\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	lp873->rev = otpid & LP873X_OTP_REV_OTP_ID;
> > > +	i2c_set_clientdata(client, lp873);
> > > +	ret = mfd_add_devices(lp873->dev, PLATFORM_DEVID_AUTO, lp873x_cells,
> > > +			      ARRAY_SIZE(lp873x_cells), NULL, 0, NULL);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static const struct of_device_id of_lp873x_match_table[] = {
> > > +	{ .compatible = "ti,lp8733", },
> > > +	{ .compatible = "ti,lp8732", },
> > > +	{}
> > > +};
> > > +MODULE_DEVICE_TABLE(of, of_lp873x_match_table);
> > > +
> > > +static const struct i2c_device_id lp873x_id_table[] = {
> > > +	{ "lp873x", LP873X },
> > > +	{ "lp8732", LP873X },
> > > +	{ "lp8733", LP873X },
> > 
> > Do you use these IDs at any point?
> 
> I have lp8733 and lp8732 at the moment. They are register exact but
> different parts none the less. Hence having separate strings. As of now no
> differences seen in gpio/regulator modules so not using them anywhere.

I have a patch-set pending on the I2C list that removes all unused
'struct i2c_device_id' tables.  To identify which ones are in use and
which ones can be removed, it would help if you could remove the
unused .id field.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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