Date:   Thu, 19 Oct 2023 17:23:59 +0100
From:   Lee Jones <lee@...nel.org>
To:     James Ogletree <james.ogletree@...nsource.cirrus.com>
Cc:     James Ogletree <james.ogletree@...rus.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Fred Treven <fred.treven@...rus.com>,
        Ben Bright <ben.bright@...rus.com>,
        linux-input@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/4] mfd: cs40l50: Add support for CS40L50 core driver

On Wed, 18 Oct 2023, James Ogletree wrote:

> From: James Ogletree <james.ogletree@...rus.com>
> 
> Introduce support for Cirrus Logic Device CS40L50: a
> haptic driver with waveform memory, integrated DSP,
> and closed-loop algorithms.
> 
> The MFD component registers and initializes the device.
> 
> Signed-off-by: James Ogletree <james.ogletree@...rus.com>
> ---
>  MAINTAINERS                 |   2 +
>  drivers/mfd/Kconfig         |  30 +++
>  drivers/mfd/Makefile        |   4 +
>  drivers/mfd/cs40l50-core.c  | 443 ++++++++++++++++++++++++++++++++++++
>  drivers/mfd/cs40l50-i2c.c   |  69 ++++++
>  drivers/mfd/cs40l50-spi.c   |  68 ++++++
>  include/linux/mfd/cs40l50.h | 198 ++++++++++++++++
>  7 files changed, 814 insertions(+)
>  create mode 100644 drivers/mfd/cs40l50-core.c
>  create mode 100644 drivers/mfd/cs40l50-i2c.c
>  create mode 100644 drivers/mfd/cs40l50-spi.c
>  create mode 100644 include/linux/mfd/cs40l50.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 57daf77bf550..08e1e9695d49 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4971,7 +4971,9 @@ L:	patches@...nsource.cirrus.com
>  S:	Supported
>  F:	Documentation/devicetree/bindings/input/cirrus,cs40l50.yaml
>  F:	drivers/input/misc/cirrus*
> +F:	drivers/mfd/cs40l*
>  F:	include/linux/input/cirrus*
> +F:	include/linux/mfd/cs40l*
>  
>  CIRRUS LOGIC DSP FIRMWARE DRIVER
>  M:	Simon Trimmer <simont@...nsource.cirrus.com>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 8b93856de432..a133d04a7859 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -2187,6 +2187,36 @@ config MCP_UCB1200_TS
>  
>  endmenu
>  
> +config MFD_CS40L50_CORE
> +	tristate
> +	select MFD_CORE
> +	select CS_DSP
> +	select REGMAP_IRQ
> +
> +config MFD_CS40L50_I2C
> +	tristate "Cirrus Logic CS40L50 (I2C)"
> +	select REGMAP_I2C
> +	select MFD_CS40L50_CORE
> +	depends on I2C
> +	help
> +	  Select this to support the Cirrus Logic CS40L50 Haptic
> +	  Driver over I2C.
> +
> +	  This driver can be built as a module. If built as a module it will be
> +	  called "cs40l50-i2c".
> +
> +config MFD_CS40L50_SPI
> +	tristate "Cirrus Logic CS40L50 (SPI)"
> +	select REGMAP_SPI
> +	select MFD_CS40L50_CORE
> +	depends on SPI
> +	help
> +	  Select this to support the Cirrus Logic CS40L50 Haptic
> +	  Driver over SPI.
> +
> +	  This driver can be built as a module. If built as a module it will be
> +	  called "cs40l50-spi".
> +
>  config MFD_VEXPRESS_SYSREG
>  	tristate "Versatile Express System Registers"
>  	depends on VEXPRESS_CONFIG && GPIOLIB
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 7ed3ef4a698c..3b1a43b3acaf 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -95,6 +95,10 @@ obj-$(CONFIG_MFD_MADERA)	+= madera.o
>  obj-$(CONFIG_MFD_MADERA_I2C)	+= madera-i2c.o
>  obj-$(CONFIG_MFD_MADERA_SPI)	+= madera-spi.o
>  
> +obj-$(CONFIG_MFD_CS40L50_CORE)	+= cs40l50-core.o
> +obj-$(CONFIG_MFD_CS40L50_I2C)	+= cs40l50-i2c.o
> +obj-$(CONFIG_MFD_CS40L50_SPI)	+= cs40l50-spi.o
> +
>  obj-$(CONFIG_TPS6105X)		+= tps6105x.o
>  obj-$(CONFIG_TPS65010)		+= tps65010.o
>  obj-$(CONFIG_TPS6507X)		+= tps6507x.o
> diff --git a/drivers/mfd/cs40l50-core.c b/drivers/mfd/cs40l50-core.c
> new file mode 100644
> index 000000000000..f1eadd80203a
> --- /dev/null
> +++ b/drivers/mfd/cs40l50-core.c
> @@ -0,0 +1,443 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * CS40L50 Advanced Haptic Driver with waveform memory,

s/Driver/device/

> + * integrated DSP, and closed-loop algorithms
> + *
> + * Copyright 2023 Cirrus Logic, Inc.
> + *

Remove this line.

No Author?

> + */
> +
> +#include <linux/gpio/consumer.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/cs40l50.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
> +
> +static const struct mfd_cell cs40l50_devs[] = {
> +	{
> +		.name = "cs40l50-vibra",
> +	},

This should be on one line.

Where are the other devices?  Without them, it's not an MFD.

> +};
> +
> +const struct regmap_config cs40l50_regmap = {
> +	.reg_bits =		32,
> +	.reg_stride =		4,
> +	.val_bits =		32,
> +	.reg_format_endian =	REGMAP_ENDIAN_BIG,
> +	.val_format_endian =	REGMAP_ENDIAN_BIG,
> +};
> +EXPORT_SYMBOL_GPL(cs40l50_regmap);
> +
> +static struct regulator_bulk_data cs40l50_supplies[] = {
> +	{
> +		.supply = "vp",
> +	},
> +	{
> +		.supply = "vio",
> +	},

One line each please.

> +};
> +
> +static int cs40l50_handle_f0_est_done(struct cs40l50_private *cs40l50)
> +{
> +	u32 f_zero;
> +	int error;
> +
> +	error = regmap_read(cs40l50->regmap, CS40L50_F0_ESTIMATION, &f_zero);
> +	if (error)
> +		return error;
> +
> +	return regmap_write(cs40l50->regmap, CS40L50_F0_STORED, f_zero);
> +}

I have no idea what this is doing (probably goes for the following
functions too.  Either give the function a friendly name or provide
commentary so people can read it.

> +static int cs40l50_handle_redc_est_done(struct cs40l50_private *cs40l50)
> +{
> +	int error, fractional, integer, stored;

err or ret is traditional.

The other variables need better nomenclature.

> +	u32 redc;

This one too.

I won't mention this again, but is likely to apply throughout.

> +
> +	error = regmap_read(cs40l50->regmap, CS40L50_RE_EST_STATUS, &redc);
> +	if (error)
> +		return error;
> +
> +	error = regmap_write(cs40l50->regmap, CS40L50_REDC_ESTIMATION, redc);
> +	if (error)
> +		return error;
> +
> +	/* Convert from Q8.15 to (Q7.17 * 29/240) */

I have no idea what this is supposed to be telling me.

> +	integer = ((redc >> 15) & 0xFF) << 17;
> +	fractional = (redc & 0x7FFF) * 4;
> +	stored = (integer | fractional) * 29 / 240;

No magic numbers.  Define them all please.

> +	return regmap_write(cs40l50->regmap, CS40L50_REDC_STORED, stored);
> +}
> +
> +static int cs40l50_error_release(struct cs40l50_private *cs40l50)
> +{
> +	int error;
> +
> +	error = regmap_write(cs40l50->regmap, CS40L50_ERR_RLS,
> +			     CS40L50_GLOBAL_ERR_RLS);
> +	if (error)
> +		return error;
> +
> +	return regmap_write(cs40l50->regmap, CS40L50_ERR_RLS, 0);
> +}
> +
> +static int cs40l50_mailbox_read_next(struct cs40l50_private *cs40l50, u32 *val)
> +{
> +	u32 rd_ptr, wt_ptr;
> +	int error;
> +
> +	error = regmap_read(cs40l50->regmap, CS40L50_MBOX_QUEUE_WT, &wt_ptr);
> +	if (error)
> +		return error;
> +
> +	error = regmap_read(cs40l50->regmap, CS40L50_MBOX_QUEUE_RD, &rd_ptr);
> +	if (error)
> +		return error;
> +
> +	if (wt_ptr == rd_ptr) {
> +		*val = 0;
> +		return 0;
> +	}
> +
> +	error = regmap_read(cs40l50->regmap, rd_ptr, val);
> +	if (error)
> +		return error;
> +
> +	rd_ptr += sizeof(u32);
> +	if (rd_ptr > CS40L50_MBOX_QUEUE_END)
> +		rd_ptr = CS40L50_MBOX_QUEUE_BASE;
> +
> +	return regmap_write(cs40l50->regmap, CS40L50_MBOX_QUEUE_RD, rd_ptr);
> +}
> +
> +static irqreturn_t cs40l50_process_mbox(int irq, void *data)
> +{
> +	struct cs40l50_private *cs40l50 = data;
> +	int error = 0;
> +	u32 val;
> +
> +	mutex_lock(&cs40l50->lock);
> +
> +	while (!cs40l50_mailbox_read_next(cs40l50, &val)) {
> +		switch (val) {
> +		case 0:
> +			mutex_unlock(&cs40l50->lock);
> +			dev_dbg(cs40l50->dev, "Reached end of queue\n");
> +			return IRQ_HANDLED;
> +		case CS40L50_MBOX_HAPTIC_TRIGGER_GPIO:
> +			dev_dbg(cs40l50->dev, "Mailbox: TRIGGER_GPIO\n");

These all appear to be no-ops?

> +			break;
> +		case CS40L50_MBOX_HAPTIC_TRIGGER_MBOX:
> +			dev_dbg(cs40l50->dev, "Mailbox: TRIGGER_MBOX\n");
> +			break;
> +		case CS40L50_MBOX_HAPTIC_TRIGGER_I2S:
> +			dev_dbg(cs40l50->dev, "Mailbox: TRIGGER_I2S\n");
> +			break;
> +		case CS40L50_MBOX_HAPTIC_COMPLETE_MBOX:
> +			dev_dbg(cs40l50->dev, "Mailbox: COMPLETE_MBOX\n");
> +			break;
> +		case CS40L50_MBOX_HAPTIC_COMPLETE_GPIO:
> +			dev_dbg(cs40l50->dev, "Mailbox: COMPLETE_GPIO\n");
> +			break;
> +		case CS40L50_MBOX_HAPTIC_COMPLETE_I2S:
> +			dev_dbg(cs40l50->dev, "Mailbox: COMPLETE_I2S\n");
> +			break;
> +		case CS40L50_MBOX_F0_EST_START:
> +			dev_dbg(cs40l50->dev, "Mailbox: F0_EST_START\n");
> +			break;
> +		case CS40L50_MBOX_F0_EST_DONE:
> +			dev_dbg(cs40l50->dev, "Mailbox: F0_EST_DONE\n");
> +			error = cs40l50_handle_f0_est_done(cs40l50);
> +			if (error)
> +				goto out_mutex;
> +			break;
> +		case CS40L50_MBOX_REDC_EST_START:
> +			dev_dbg(cs40l50->dev, "Mailbox: REDC_EST_START\n");
> +			break;
> +		case CS40L50_MBOX_REDC_EST_DONE:
> +			dev_dbg(cs40l50->dev, "Mailbox: REDC_EST_DONE\n");
> +			error = cs40l50_handle_redc_est_done(cs40l50);
> +			if (error)
> +				goto out_mutex;
> +			break;
> +		case CS40L50_MBOX_LE_EST_START:
> +			dev_dbg(cs40l50->dev, "Mailbox: LE_EST_START\n");
> +			break;
> +		case CS40L50_MBOX_LE_EST_DONE:
> +			dev_dbg(cs40l50->dev, "Mailbox: LE_EST_DONE\n");
> +			break;
> +		case CS40L50_MBOX_AWAKE:
> +			dev_dbg(cs40l50->dev, "Mailbox: AWAKE\n");
> +			break;
> +		case CS40L50_MBOX_INIT:
> +			dev_dbg(cs40l50->dev, "Mailbox: INIT\n");
> +			break;
> +		case CS40L50_MBOX_ACK:
> +			dev_dbg(cs40l50->dev, "Mailbox: ACK\n");
> +			break;
> +		case CS40L50_MBOX_ERR_EVENT_UNMAPPED:
> +			dev_err(cs40l50->dev, "Unmapped event\n");
> +			break;
> +		case CS40L50_MBOX_ERR_EVENT_MODIFY:
> +			dev_err(cs40l50->dev, "Failed to modify event index\n");
> +			break;
> +		case CS40L50_MBOX_ERR_NULLPTR:
> +			dev_err(cs40l50->dev, "Null pointer\n");
> +			break;
> +		case CS40L50_MBOX_ERR_BRAKING:
> +			dev_err(cs40l50->dev, "Braking not in progress\n");
> +			break;
> +		case CS40L50_MBOX_ERR_INVAL_SRC:
> +			dev_err(cs40l50->dev, "Suspend/resume invalid source\n");
> +			break;
> +		case CS40L50_MBOX_ERR_ENABLE_RANGE:
> +			dev_err(cs40l50->dev, "GPIO enable out of range\n");
> +			break;
> +		case CS40L50_MBOX_ERR_GPIO_UNMAPPED:
> +			dev_err(cs40l50->dev, "GPIO not mapped\n");
> +			break;
> +		case CS40L50_MBOX_ERR_ISR_RANGE:
> +			dev_err(cs40l50->dev, "GPIO ISR out of range\n");
> +			break;
> +		case CS40L50_MBOX_PERMANENT_SHORT:
> +			dev_crit(cs40l50->dev, "Permanent short detected\n");
> +			break;
> +		case CS40L50_MBOX_RUNTIME_SHORT:
> +			dev_err(cs40l50->dev, "Runtime short detected\n");
> +			error = cs40l50_error_release(cs40l50);
> +			if (error)
> +				goto out_mutex;
> +			break;
> +		default:
> +			dev_err(cs40l50->dev, "Payload %#X not recognized\n", val);
> +			error = -EINVAL;
> +			goto out_mutex;
> +		}
> +	}
> +
> +	error = -EIO;
> +
> +out_mutex:
> +	mutex_unlock(&cs40l50->lock);
> +
> +	return IRQ_RETVAL(!error);
> +}

Should the last two drivers live in drivers/mailbox?

> +static irqreturn_t cs40l50_error(int irq, void *data);

Why is this being forward declared?

> +static const struct cs40l50_irq cs40l50_irqs[] = {
> +	CS40L50_IRQ(AMP_SHORT,		"Amp short",		error),

I assume that last parameter is half of a function name.

Better to have 2 different structures and do 2 requests I feel.

> +	CS40L50_IRQ(VIRT2_MBOX,		"Mailbox",		process_mbox),
> +	CS40L50_IRQ(TEMP_ERR,		"Overtemperature",	error),
> +	CS40L50_IRQ(BST_UVP,		"Boost undervoltage",	error),
> +	CS40L50_IRQ(BST_SHORT,		"Boost short",		error),
> +	CS40L50_IRQ(BST_ILIMIT,		"Boost current limit",	error),
> +	CS40L50_IRQ(UVLO_VDDBATT,	"Boost UVLO",		error),
> +	CS40L50_IRQ(GLOBAL_ERROR,	"Global",		error),
> +};
> +
> +static irqreturn_t cs40l50_error(int irq, void *data)
> +{
> +	struct cs40l50_private *cs40l50 = data;
> +
> +	dev_err(cs40l50->dev, "%s error\n", cs40l50_irqs[irq].name);

> +	return IRQ_RETVAL(!cs40l50_error_release(cs40l50));

Please break the function out of the parentheses.

We don't tend to put functions in if()s either.

> +}
> +
> +static const struct regmap_irq cs40l50_reg_irqs[] = {
> +	CS40L50_REG_IRQ(IRQ1_INT_1,	AMP_SHORT),

I commented on these where you defined them - see below.

> +	CS40L50_REG_IRQ(IRQ1_INT_2,	VIRT2_MBOX),
> +	CS40L50_REG_IRQ(IRQ1_INT_8,	TEMP_ERR),
> +	CS40L50_REG_IRQ(IRQ1_INT_9,	BST_UVP),
> +	CS40L50_REG_IRQ(IRQ1_INT_9,	BST_SHORT),
> +	CS40L50_REG_IRQ(IRQ1_INT_9,	BST_ILIMIT),
> +	CS40L50_REG_IRQ(IRQ1_INT_10,	UVLO_VDDBATT),
> +	CS40L50_REG_IRQ(IRQ1_INT_18,	GLOBAL_ERROR),
> +};
> +
> +static struct regmap_irq_chip cs40l50_irq_chip = {
> +	.name =			"CS40L50 IRQ Controller",
> +
> +	.status_base =		CS40L50_IRQ1_INT_1,
> +	.mask_base =		CS40L50_IRQ1_MASK_1,
> +	.ack_base =		CS40L50_IRQ1_INT_1,
> +	.num_regs =		22,
> +
> +	.irqs =			cs40l50_reg_irqs,
> +	.num_irqs =		ARRAY_SIZE(cs40l50_reg_irqs),
> +
> +	.runtime_pm =		true,
> +};
> +
> +static int cs40l50_irq_init(struct cs40l50_private *cs40l50)
> +{
> +	struct device *dev = cs40l50->dev;
> +	int error, i, irq;
> +
> +	error = devm_regmap_add_irq_chip(dev, cs40l50->regmap, cs40l50->irq,
> +					 IRQF_ONESHOT | IRQF_SHARED, 0,
> +					 &cs40l50_irq_chip, &cs40l50->irq_data);
> +	if (error)
> +		return error;
> +
> +	for (i = 0; i < ARRAY_SIZE(cs40l50_irqs); i++) {
> +		irq = regmap_irq_get_virq(cs40l50->irq_data, cs40l50_irqs[i].irq);
> +		if (irq < 0) {
> +			dev_err(dev, "Failed getting %s\n", cs40l50_irqs[i].name);
> +			return irq;
> +		}
> +
> +		error = devm_request_threaded_irq(dev, irq, NULL,
> +						  cs40l50_irqs[i].handler,
> +						  IRQF_ONESHOT | IRQF_SHARED,
> +						  cs40l50_irqs[i].name, cs40l50);
> +		if (error) {
> +			dev_err(dev, "Failed requesting %s\n", cs40l50_irqs[i].name);
> +			return error;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int cs40l50_part_num_resolve(struct cs40l50_private *cs40l50)
> +{
> +	struct device *dev = cs40l50->dev;
> +	int error;
> +
> +	error = regmap_read(cs40l50->regmap, CS40L50_DEVID, &cs40l50->devid);
> +	if (error)
> +		return error;
> +
> +	if (cs40l50->devid != CS40L50_DEVID_A) {
> +		dev_err(dev, "Invalid device ID: %#010X\n", cs40l50->devid);
> +		return -EINVAL;
> +	}
> +
> +	error = regmap_read(cs40l50->regmap, CS40L50_REVID, &cs40l50->revid);
> +	if (error)
> +		return error;
> +
> +	if (cs40l50->revid != CS40L50_REVID_B0) {
> +		dev_err(dev, "Invalid revision: %#04X\n", cs40l50->revid);
> +		return -EINVAL;
> +	}
> +
> +	dev_info(dev, "Cirrus Logic CS40L50 revision %02X\n", cs40l50->revid);
> +
> +	return 0;
> +}
> +
> +int cs40l50_probe(struct cs40l50_private *cs40l50)

Previous Cirrus drivers have omitted the "_private" part, which I think
is better.  "_ddata" is also common and acceptable.

> +{
> +	struct device *dev = cs40l50->dev;
> +	int error;
> +
> +	mutex_init(&cs40l50->lock);

Don't you need to destroy this in the error path?

> +	cs40l50->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(cs40l50->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(cs40l50->reset_gpio),
> +				     "Failed getting reset GPIO\n");
> +
> +	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(cs40l50_supplies),
> +					cs40l50_supplies);
> +	if (error)
> +		goto err_reset;
> +
> +	error = regulator_bulk_enable(ARRAY_SIZE(cs40l50_supplies),
> +				      cs40l50_supplies);
> +	if (error)
> +		goto err_reset;
> +
> +	usleep_range(CS40L50_CP_READY_US, CS40L50_CP_READY_US + 100);

A comment for why this is required please.

And why 100us is appropriate.

> +	gpiod_set_value_cansleep(cs40l50->reset_gpio, 1);
> +
> +	usleep_range(CS40L50_CP_READY_US, CS40L50_CP_READY_US + 1000);

As above.

> +	pm_runtime_set_autosuspend_delay(cs40l50->dev, CS40L50_AUTOSUSPEND_MS);
> +	pm_runtime_use_autosuspend(cs40l50->dev);
> +	pm_runtime_set_active(cs40l50->dev);
> +	pm_runtime_get_noresume(cs40l50->dev);
> +	devm_pm_runtime_enable(cs40l50->dev);
> +
> +	error = cs40l50_part_num_resolve(cs40l50);

*_get_model()?

> +	if (error)
> +		goto err_supplies;
> +
> +	error = cs40l50_irq_init(cs40l50);
> +	if (error)
> +		goto err_supplies;
> +
> +	error = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE, cs40l50_devs,
> +				     ARRAY_SIZE(cs40l50_devs), NULL, 0, NULL);
> +	if (error)
> +		goto err_supplies;
> +
> +	pm_runtime_mark_last_busy(cs40l50->dev);
> +	pm_runtime_put_autosuspend(cs40l50->dev);
> +
> +	return 0;
> +
> +err_supplies:
> +	regulator_bulk_disable(ARRAY_SIZE(cs40l50_supplies), cs40l50_supplies);
> +err_reset:
> +	gpiod_set_value_cansleep(cs40l50->reset_gpio, 0);
> +
> +	return error;
> +}
> +EXPORT_SYMBOL_GPL(cs40l50_probe);
> +
> +int cs40l50_remove(struct cs40l50_private *cs40l50)
> +{
> +	regulator_bulk_disable(ARRAY_SIZE(cs40l50_supplies), cs40l50_supplies);
> +	gpiod_set_value_cansleep(cs40l50->reset_gpio, 1);

mutex_destroy()?

> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(cs40l50_remove);
> +
> +static int cs40l50_runtime_suspend(struct device *dev)
> +{
> +	struct cs40l50_private *cs40l50 = dev_get_drvdata(dev);
> +
> +	return regmap_write(cs40l50->regmap, CS40L50_DSP_MBOX, CS40L50_ALLOW_HIBER);
> +}
> +
> +static int cs40l50_runtime_resume(struct device *dev)
> +{
> +	struct cs40l50_private *cs40l50 = dev_get_drvdata(dev);
> +	int error, i;
> +	u32 val;
> +
> +	/* Device NAKs when exiting hibernation, so optionally retry here. */

A comment - hoorah!

> +	for (i = 0; i < CS40L50_DSP_TIMEOUT_COUNT; i++) {
> +		error = regmap_write(cs40l50->regmap, CS40L50_DSP_MBOX,
> +				     CS40L50_PREVENT_HIBER);
> +		if (!error)
> +			break;
> +
> +		usleep_range(CS40L50_DSP_POLL_US, CS40L50_DSP_POLL_US + 100);
> +	}
> +
> +	for (; i < CS40L50_DSP_TIMEOUT_COUNT; i++) {

So, the amount of time this section is given is entirely based on how
well the previous section did.  Is that intentional?

Perhaps some comments to help straighten out your intentions.

> +		error = regmap_read(cs40l50->regmap, CS40L50_DSP_MBOX, &val);
> +		if (!error && val == 0)
> +			return 0;
> +
> +		usleep_range(CS40L50_DSP_POLL_US, CS40L50_DSP_POLL_US + 100);
> +	}
> +
> +	return error ? error : -ETIMEDOUT;

return error ?: -ETIMEDOUT;

> +}
> +
> +EXPORT_GPL_DEV_PM_OPS(cs40l50_pm_ops) = {
> +	RUNTIME_PM_OPS(cs40l50_runtime_suspend, cs40l50_runtime_resume, NULL)
> +};
> +
> +MODULE_DESCRIPTION("CS40L50 Advanced Haptic Driver");
> +MODULE_AUTHOR("James Ogletree, Cirrus Logic Inc. <james.ogletree@...rus.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/mfd/cs40l50-i2c.c b/drivers/mfd/cs40l50-i2c.c
> new file mode 100644
> index 000000000000..be1b130eb94b
> --- /dev/null
> +++ b/drivers/mfd/cs40l50-i2c.c
> @@ -0,0 +1,69 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * CS40L50 I2C Driver

This is not an I2C driver.

Best to describe the hardware rather that the "driver".

> + *
> + * Copyright 2023 Cirrus Logic, Inc.
> + *

Remove please.

> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/mfd/cs40l50.h>
> +
> +static int cs40l50_i2c_probe(struct i2c_client *client,
> +			     const struct i2c_device_id *id)
> +{
> +	struct device *dev = &client->dev;
> +	struct cs40l50_private *cs40l50;
> +
> +	cs40l50 = devm_kzalloc(dev, sizeof(*cs40l50), GFP_KERNEL);
> +	if (!cs40l50)
> +		return -ENOMEM;
> +
> +	i2c_set_clientdata(client, cs40l50);
> +
> +	cs40l50->regmap = devm_regmap_init_i2c(client, &cs40l50_regmap);
> +	if (IS_ERR(cs40l50->regmap))
> +		return dev_err_probe(cs40l50->dev, PTR_ERR(cs40l50->regmap),
> +				     "Failed to initialize register map\n");
> +
> +	cs40l50->dev = dev;
> +	cs40l50->irq = client->irq;
> +
> +	return cs40l50_probe(cs40l50);
> +}
> +
> +static void cs40l50_i2c_remove(struct i2c_client *client)
> +{
> +	struct cs40l50_private *cs40l50 = i2c_get_clientdata(client);
> +
> +	cs40l50_remove(cs40l50);
> +}
> +
> +static const struct i2c_device_id cs40l50_id_i2c[] = {
> +	{"cs40l50", 0},

This second parameter shouldn't be required now.

> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, cs40l50_id_i2c);
> +
> +static const struct of_device_id cs40l50_of_match[] = {
> +	{ .compatible = "cirrus,cs40l50" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, cs40l50_of_match);
> +
> +static struct i2c_driver cs40l50_i2c_driver = {
> +	.driver = {
> +		.name = "cs40l50",
> +		.of_match_table = cs40l50_of_match,
> +		.pm = pm_ptr(&cs40l50_pm_ops),
> +	},
> +	.id_table = cs40l50_id_i2c,
> +	.probe = cs40l50_i2c_probe,
> +	.remove = cs40l50_i2c_remove,
> +};
> +

Remove this line.

> +module_i2c_driver(cs40l50_i2c_driver);
> +
> +MODULE_DESCRIPTION("CS40L50 I2C Driver");
> +MODULE_AUTHOR("James Ogletree, Cirrus Logic Inc. <james.ogletree@...rus.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/mfd/cs40l50-spi.c b/drivers/mfd/cs40l50-spi.c
> new file mode 100644
> index 000000000000..8311d48efedf
> --- /dev/null
> +++ b/drivers/mfd/cs40l50-spi.c
> @@ -0,0 +1,68 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * CS40L50 SPI Driver
> + *
> + * Copyright 2023 Cirrus Logic, Inc.
> + *

Same comments as before.

> + */
> +
> +#include <linux/input/cs40l50.h>
> +#include <linux/mfd/spi.h>
> +
> +static int cs40l50_spi_probe(struct spi_device *spi)
> +{
> +	struct cs40l50_private *cs40l50;
> +	struct device *dev = &spi->dev;
> +
> +	cs40l50 = devm_kzalloc(dev, sizeof(*cs40l50), GFP_KERNEL);
> +	if (!cs40l50)
> +		return -ENOMEM;
> +
> +	spi_set_drvdata(spi, cs40l50);
> +
> +	cs40l50->regmap = devm_regmap_init_spi(spi, &cs40l50_regmap);
> +	if (IS_ERR(cs40l50->regmap))
> +		return dev_err_probe(cs40l50->dev, PTR_ERR(cs40l50->regmap),
> +				     "Failed to initialize register map\n");
> +
> +	cs40l50->dev = dev;
> +	cs40l50->irq = spi->irq;
> +
> +	return cs40l50_probe(cs40l50);
> +}
> +
> +static void cs40l50_spi_remove(struct spi_device *spi)
> +{
> +	struct cs40l50_private *cs40l50 = spi_get_drvdata(spi);
> +
> +	cs40l50_remove(cs40l50);
> +}
> +
> +static const struct spi_device_id cs40l50_id_spi[] = {
> +	{"cs40l50", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(spi, cs40l50_id_spi);
> +
> +static const struct of_device_id cs40l50_of_match[] = {
> +	{ .compatible = "cirrus,cs40l50" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, cs40l50_of_match);
> +
> +static struct spi_driver cs40l50_spi_driver = {
> +	.driver = {
> +		.name = "cs40l50",
> +		.of_match_table = cs40l50_of_match,
> +		.pm = pm_ptr(&cs40l50_pm_ops),
> +	},
> +	.id_table = cs40l50_id_spi,
> +	.probe = cs40l50_spi_probe,
> +	.remove = cs40l50_spi_remove,
> +};
> +
> +module_spi_driver(cs40l50_spi_driver);
> +
> +MODULE_DESCRIPTION("CS40L50 SPI Driver");
> +MODULE_AUTHOR("James Ogletree, Cirrus Logic Inc. <james.ogletree@...rus.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/cs40l50.h b/include/linux/mfd/cs40l50.h
> new file mode 100644
> index 000000000000..c625a999a5ae
> --- /dev/null
> +++ b/include/linux/mfd/cs40l50.h
> @@ -0,0 +1,198 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + *
> + * CS40L50 Advanced Haptic Driver with waveform memory,
> + * integrated DSP, and closed-loop algorithms
> + *
> + * Copyright 2023 Cirrus Logic, Inc.
> + *
> + */
> +
> +#ifndef __CS40L50_H__
> +#define __CS40L50_H__
> +
> +#include <linux/firmware/cirrus/cs_dsp.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/input.h>
> +#include <linux/input/cirrus_haptics.h>
> +#include <linux/interrupt.h>
> +#include <linux/pm.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +
> +/* Power Supply Configuration */
> +#define CS40L50_BLOCK_ENABLES2			0x201C
> +#define CS40L50_ERR_RLS				0x2034
> +#define CS40L50_PWRMGT_CTL			0x2900
> +#define CS40L50_BST_LPMODE_SEL			0x3810
> +#define CS40L50_DCM_LOW_POWER		0x1
> +#define CS40L50_OVERTEMP_WARN		0x4000010
> +
> +/* Interrupts */
> +#define CS40L50_IRQ1_INT_1			0xE010
> +#define CS40L50_IRQ1_INT_2			0xE014
> +#define CS40L50_IRQ1_INT_8			0xE02C
> +#define CS40L50_IRQ1_INT_9			0xE030
> +#define CS40L50_IRQ1_INT_10			0xE034
> +#define CS40L50_IRQ1_INT_18			0xE054
> +#define CS40L50_IRQ1_MASK_1			0xE090
> +#define CS40L50_IRQ1_MASK_2			0xE094
> +#define CS40L50_IRQ1_MASK_20			0xE0DC
> +#define CS40L50_IRQ_MASK_2_OVERRIDE	0xFFDF7FFF
> +#define CS40L50_IRQ_MASK_20_OVERRIDE	0x15C01000
> +#define CS40L50_AMP_SHORT_MASK		BIT(31)
> +#define CS40L50_VIRT2_MBOX_MASK		BIT(21)
> +#define CS40L50_TEMP_ERR_MASK		BIT(31)
> +#define CS40L50_BST_UVP_MASK		BIT(6)
> +#define CS40L50_BST_SHORT_MASK		BIT(7)
> +#define CS40L50_BST_ILIMIT_MASK		BIT(8)
> +#define CS40L50_UVLO_VDDBATT_MASK	BIT(16)
> +#define CS40L50_GLOBAL_ERROR_MASK	BIT(15)
> +#define CS40L50_GLOBAL_ERR_RLS		BIT(11)
> +#define CS40L50_IRQ(_irq, _name, _hand)		\
> +	{					\
> +		.irq = CS40L50_ ## _irq ## _IRQ,\
> +		.name = _name,			\
> +		.handler = cs40l50_ ## _hand,	\
> +	}
> +#define CS40L50_REG_IRQ(_reg, _irq)					\

Please don't reinvent the wheel:

  REGMAP_IRQ_REG_LINE()

> +	[CS40L50_ ## _irq ## _IRQ] = {					\
> +		.reg_offset = (CS40L50_ ## _reg) - CS40L50_IRQ1_INT_1,	\
> +		.mask = CS40L50_ ## _irq ## _MASK			\
> +	}
> +
> +/* Mailbox Inbound Commands */
> +#define CS40L50_RAM_BANK_INDEX_START	0x1000000
> +#define CS40L50_RTH_INDEX_START		0x1400000
> +#define CS40L50_RTH_INDEX_END		0x1400001
> +#define CS40L50_ROM_BANK_INDEX_START	0x1800000
> +#define CS40L50_ROM_BANK_INDEX_END	0x180001A
> +#define CS40L50_PREVENT_HIBER		0x2000003
> +#define CS40L50_ALLOW_HIBER		0x2000004
> +#define CS40L50_OWT_PUSH		0x3000008
> +#define CS40L50_STOP_PLAYBACK		0x5000000
> +#define CS40L50_OWT_DELETE		0xD000000
> +
> +/* Mailbox Outbound Commands */
> +#define CS40L50_MBOX_QUEUE_BASE				0x11004
> +#define CS40L50_MBOX_QUEUE_END				0x1101C
> +#define CS40L50_DSP_MBOX				0x11020
> +#define CS40L50_MBOX_QUEUE_WT				0x28042C8
> +#define CS40L50_MBOX_QUEUE_RD				0x28042CC
> +#define CS40L50_MBOX_HAPTIC_COMPLETE_MBOX	0x1000000
> +#define CS40L50_MBOX_HAPTIC_COMPLETE_GPIO	0x1000001
> +#define CS40L50_MBOX_HAPTIC_COMPLETE_I2S	0x1000002
> +#define CS40L50_MBOX_HAPTIC_TRIGGER_MBOX	0x1000010
> +#define CS40L50_MBOX_HAPTIC_TRIGGER_GPIO	0x1000011
> +#define CS40L50_MBOX_HAPTIC_TRIGGER_I2S		0x1000012
> +#define CS40L50_MBOX_INIT			0x2000000
> +#define CS40L50_MBOX_AWAKE			0x2000002
> +#define CS40L50_MBOX_F0_EST_START		0x7000011
> +#define CS40L50_MBOX_F0_EST_DONE		0x7000021
> +#define CS40L50_MBOX_REDC_EST_START		0x7000012
> +#define CS40L50_MBOX_REDC_EST_DONE		0x7000022
> +#define CS40L50_MBOX_LE_EST_START		0x7000014
> +#define CS40L50_MBOX_LE_EST_DONE		0x7000024
> +#define CS40L50_MBOX_ACK			0xA000000
> +#define CS40L50_MBOX_PANIC			0xC000000
> +#define CS40L50_MBOX_WATERMARK			0xD000000
> +#define CS40L50_MBOX_ERR_EVENT_UNMAPPED		0xC0004B3
> +#define CS40L50_MBOX_ERR_EVENT_MODIFY		0xC0004B4
> +#define CS40L50_MBOX_ERR_NULLPTR		0xC0006A5
> +#define CS40L50_MBOX_ERR_BRAKING		0xC0006A8
> +#define CS40L50_MBOX_ERR_INVAL_SRC		0xC0006AC
> +#define CS40L50_MBOX_ERR_ENABLE_RANGE		0xC000836
> +#define CS40L50_MBOX_ERR_GPIO_UNMAPPED		0xC000837
> +#define CS40L50_MBOX_ERR_ISR_RANGE		0xC000838
> +#define CS40L50_MBOX_PERMANENT_SHORT		0xC000C1C
> +#define CS40L50_MBOX_RUNTIME_SHORT		0xC000C1D
> +
> +/* DSP */
> +#define CS40L50_DSP1_XMEM_PACKED_0		0x2000000
> +#define CS40L50_DSP1_XMEM_UNPACKED32_0		0x2400000
> +#define CS40L50_SYS_INFO_ID			0x25E0000
> +#define CS40L50_DSP1_XMEM_UNPACKED24_0		0x2800000
> +#define CS40L50_RAM_INIT			0x28021DC
> +#define CS40L50_POWER_ON_SEQ			0x2804320
> +#define CS40L50_OWT_BASE			0x2805C34
> +#define CS40L50_NUM_OF_WAVES			0x280CB4C
> +#define CS40L50_CORE_BASE			0x2B80000
> +#define CS40L50_CCM_CORE_CONTROL		0x2BC1000
> +#define CS40L50_DSP1_YMEM_PACKED_0		0x2C00000
> +#define CS40L50_DSP1_YMEM_UNPACKED32_0		0x3000000
> +#define CS40L50_DSP1_YMEM_UNPACKED24_0		0x3400000
> +#define CS40L50_DSP1_PMEM_0			0x3800000
> +#define CS40L50_DSP1_PMEM_5114			0x3804FE8
> +#define CS40L50_MEM_RDY_HW		0x2
> +#define CS40L50_RAM_INIT_FLAG		0x1
> +#define CS40L50_CLOCK_DISABLE		0x80
> +#define CS40L50_CLOCK_ENABLE		0x281
> +#define CS40L50_DSP_POLL_US		1000
> +#define CS40L50_DSP_TIMEOUT_COUNT	100
> +#define CS40L50_CP_READY_US		2200
> +#define CS40L50_PSEQ_SIZE		200
> +#define CS40L50_AUTOSUSPEND_MS		2000
> +
> +/* Firmware */
> +#define CS40L50_FW			"cs40l50.wmfw"
> +#define CS40L50_WT			"cs40l50.bin"
> +
> +/* Calibration */
> +#define CS40L50_REDC_ESTIMATION		0x2802F7C
> +#define CS40L50_F0_ESTIMATION		0x2802F84
> +#define CS40L50_F0_STORED		0x2805C00
> +#define CS40L50_REDC_STORED		0x2805C04
> +#define CS40L50_RE_EST_STATUS		0x3401B40
> +
> +/* Open wavetable */
> +#define CS40L50_OWT_SIZE		0x2805C38
> +#define CS40L50_OWT_NEXT		0x2805C3C
> +#define CS40L50_NUM_OF_OWT_WAVES	0x2805C40
> +
> +/* GPIO */
> +#define CS40L50_GPIO_BASE		0x2804140
> +
> +/* Device */
> +#define CS40L50_DEVID			0x0
> +#define CS40L50_REVID			0x4
> +#define CS40L50_DEVID_A		0x40A50
> +#define CS40L50_REVID_B0	0xB0
> +
> +enum cs40l50_irq_list {
> +	CS40L50_GLOBAL_ERROR_IRQ,
> +	CS40L50_UVLO_VDDBATT_IRQ,
> +	CS40L50_BST_ILIMIT_IRQ,
> +	CS40L50_BST_SHORT_IRQ,
> +	CS40L50_BST_UVP_IRQ,
> +	CS40L50_TEMP_ERR_IRQ,
> +	CS40L50_VIRT2_MBOX_IRQ,
> +	CS40L50_AMP_SHORT_IRQ,
> +};
> +
> +struct cs40l50_irq {
> +	const char *name;
> +	int irq;
> +	irqreturn_t (*handler)(int irq, void *data);
> +};
> +
> +struct cs40l50_private {
> +	struct device *dev;
> +	struct regmap *regmap;
> +	struct cs_dsp dsp;
> +	struct mutex lock;
> +	struct gpio_desc *reset_gpio;
> +	struct regmap_irq_chip_data *irq_data;
> +	struct input_dev *input;

Where is this used?

> +	const struct firmware *wmfw;

Or this.

> +	struct cs_hap haptics;

Or this?

> +	u32 devid;
> +	u32 revid;

Are these used after they're set?

> +	int irq;
> +};
> +
> +int cs40l50_probe(struct cs40l50_private *cs40l50);
> +int cs40l50_remove(struct cs40l50_private *cs40l50);
> +
> +extern const struct regmap_config cs40l50_regmap;
> +extern const struct dev_pm_ops cs40l50_pm_ops;
> +
> +#endif /* __CS40L50_H__ */
> -- 
> 2.25.1
> 

-- 
0)
Lee Jones [李琼斯]

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