Re: [PATCH v4 2/9] mfd: Add ST Multi-Function eXpander (STMFX) core driver

[Lee Jones]

On Wed, 27 Feb 2019, Amelie Delaunay wrote:

> STMicroelectronics Multi-Function eXpander (STMFX) is a slave controller
> using I2C for communication with the main MCU. Main features are:
> - 16 fast GPIOs individually configurable in input/output
> - 8 alternate GPIOs individually configurable in input/output when other
> STMFX functions are not used
> - Main MCU IDD measurement
> - Resistive touchscreen controller
> 
> Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
> ---
>  drivers/mfd/Kconfig       |  13 ++
>  drivers/mfd/Makefile      |   2 +-
>  drivers/mfd/stmfx.c       | 568 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/stmfx.h | 123 ++++++++++
>  4 files changed, 705 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/mfd/stmfx.c
>  create mode 100644 include/linux/mfd/stmfx.h

Very nice first attempt for what is a pretty complex driver.

Just a couple of nits below.

[...]

> +static int stmfx_chip_init(struct i2c_client *client)
> +{
> +	struct stmfx *stmfx = i2c_get_clientdata(client);
> +	u32 id;
> +	u8 version[2];
> +	int ret;
> +
> +	stmfx->vdd = devm_regulator_get_optional(&client->dev, "vdd");
> +	if (IS_ERR(stmfx->vdd)) {
> +		ret = PTR_ERR(stmfx->vdd);
> +		if (ret != -ENODEV) {
> +			if (ret != -EPROBE_DEFER)
> +				dev_err(&client->dev,
> +					"No VDD regulator found:%d\n", ret);

Actually -ENODEV means this, which is okay.

In this case we failed to obtain a provided regulator.

> +			return ret;
> +		}
> +	} else {

	if (IS_ERR(stmfx->vdd) && PTR_ERR(stmfx->vdd) == -EPROBE_DEFER) {
		return PTR_ERR(stmfx->vdd);
	} else (IS_ERR(stmfx->vdd) && PTR_ERR(stmfx->vdd) == -ENODEV) {
		stmfx->vdd = NULL;
	} else (IS_ERR(stmfx->vdd))) {
		dev_err(&client->dev, "Failed to get VDD regulator:%d\n", ret);
		return PTR_ERR(stmfx->vdd);
	}

	if (stmfx->vdd) {

> +		ret = regulator_enable(stmfx->vdd);
> +		if (ret) {
> +			dev_err(&client->dev, "VDD enable failed: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +

[...]

> +static const struct resource stmfx_ts_resources[] = {
> +	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_DET),
> +	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_NE),
> +	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_TH),
> +	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_FULL),
> +	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_OVF),
> +};

Please move everything from here --------------->

> +static struct mfd_cell stmfx_cells[] = {
> +	{
> +		.of_compatible = "st,stmfx-0300-pinctrl",
> +		.name = "stmfx-pinctrl",
> +		.resources = stmfx_pinctrl_resources,
> +		.num_resources = ARRAY_SIZE(stmfx_pinctrl_resources),
> +	},
> +	{
> +		.of_compatible = "st,stmfx-0300-idd",
> +		.name = "stmfx-idd",
> +		.resources = stmfx_idd_resources,
> +		.num_resources = ARRAY_SIZE(stmfx_idd_resources),
> +	},
> +	{
> +		.of_compatible = "st,stmfx-0300-ts",
> +		.name = "stmfx-ts",
> +		.resources = stmfx_ts_resources,
> +		.num_resources = ARRAY_SIZE(stmfx_ts_resources),
> +	},
> +};
> +
> +static bool stmfx_reg_volatile(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case STMFX_REG_SYS_CTRL:
> +	case STMFX_REG_IRQ_SRC_EN:
> +	case STMFX_REG_IRQ_PENDING:
> +	case STMFX_REG_IRQ_GPI_PENDING1:
> +	case STMFX_REG_IRQ_GPI_PENDING2:
> +	case STMFX_REG_IRQ_GPI_PENDING3:
> +	case STMFX_REG_GPIO_STATE1:
> +	case STMFX_REG_GPIO_STATE2:
> +	case STMFX_REG_GPIO_STATE3:
> +	case STMFX_REG_IRQ_GPI_SRC1:
> +	case STMFX_REG_IRQ_GPI_SRC2:
> +	case STMFX_REG_IRQ_GPI_SRC3:
> +	case STMFX_REG_GPO_SET1:
> +	case STMFX_REG_GPO_SET2:
> +	case STMFX_REG_GPO_SET3:
> +	case STMFX_REG_GPO_CLR1:
> +	case STMFX_REG_GPO_CLR2:
> +	case STMFX_REG_GPO_CLR3:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool stmfx_reg_writeable(struct device *dev, unsigned int reg)
> +{
> +	return (reg >= STMFX_REG_SYS_CTRL);
> +}
> +
> +static const struct regmap_config stmfx_regmap_config = {
> +	.reg_bits	= 8,
> +	.reg_stride	= 1,
> +	.val_bits	= 8,
> +	.max_register	= STMFX_REG_MAX,
> +	.volatile_reg	= stmfx_reg_volatile,
> +	.writeable_reg	= stmfx_reg_writeable,
> +	.cache_type	= REGCACHE_RBTREE,
> +};

----------------------->

... to here, up to the top, just below the includes.

> +static int stmfx_probe(struct i2c_client *client,
> +		       const struct i2c_device_id *id)
> +{
> +	struct device *dev = &client->dev;
> +	struct stmfx *stmfx;
> +	int i, ret;
> +
> +	stmfx = devm_kzalloc(dev, sizeof(*stmfx), GFP_KERNEL);
> +	if (!stmfx)
> +		return -ENOMEM;
> +
> +	i2c_set_clientdata(client, stmfx);
> +
> +	stmfx->dev = dev;
> +
> +	stmfx->map = devm_regmap_init_i2c(client, &stmfx_regmap_config);
> +	if (IS_ERR(stmfx->map)) {
> +		ret = PTR_ERR(stmfx->map);
> +		dev_err(dev, "Failed to allocate register map: %d\n", ret);
> +		return ret;
> +	}
> +
> +	mutex_init(&stmfx->lock);
> +
> +	ret = stmfx_chip_init(client);
> +	if (ret) {
> +		if (ret == -ETIMEDOUT)
> +			return -EPROBE_DEFER;
> +		return ret;
> +	}
> +
> +	if (client->irq < 0) {
> +		dev_err(dev, "Failed to get IRQ: %d\n", client->irq);
> +		ret = client->irq;
> +		goto err_chip_exit;
> +	}
> +
> +	ret = stmfx_irq_init(client);
> +	if (ret)
> +		goto err_chip_exit;
> +
> +	for (i = 0; i < ARRAY_SIZE(stmfx_cells); i++) {
> +		stmfx_cells[i].platform_data = stmfx;
> +		stmfx_cells[i].pdata_size = sizeof(struct stmfx);
> +	}

Pass this though dev_get_drvdata() instead.

...

Actually, didn't you already set this with i2c_set_clientdata()?  That
does exactly the same thing.  So you can get this back from the client
via i2c_get_clientdata().  No need to send it though platform data.

> +	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
> +				   stmfx_cells, ARRAY_SIZE(stmfx_cells), NULL,
> +				   0, stmfx->irq_domain);
> +	if (ret)
> +		goto err_irq_exit;
> +
> +	return 0;
> +
> +err_irq_exit:
> +	stmfx_irq_exit(client);
> +err_chip_exit:
> +	stmfx_chip_exit(client);
> +
> +	return ret;
> +}
> +
> +static int stmfx_remove(struct i2c_client *client)
> +{
> +	stmfx_irq_exit(client);
> +
> +	return stmfx_chip_exit(client);
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int stmfx_backup_regs(struct stmfx *stmfx)
> +{
> +	int ret;
> +
> +	ret = regmap_raw_read(stmfx->map, STMFX_REG_SYS_CTRL,
> +			      &stmfx->bkp_sysctrl, sizeof(stmfx->bkp_sysctrl));
> +	if (ret)
> +		return ret;

'\n' here.

> +	ret = regmap_raw_read(stmfx->map, STMFX_REG_IRQ_OUT_PIN,
> +			      &stmfx->bkp_irqoutpin,
> +			      sizeof(stmfx->bkp_irqoutpin));
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int stmfx_restore_regs(struct stmfx *stmfx)
> +{
> +	int ret;
> +
> +	ret = regmap_raw_write(stmfx->map, STMFX_REG_SYS_CTRL,
> +			       &stmfx->bkp_sysctrl, sizeof(stmfx->bkp_sysctrl));
> +	if (ret)
> +		return ret;

'\n' here.

> +	ret = regmap_raw_write(stmfx->map, STMFX_REG_IRQ_OUT_PIN,
> +			       &stmfx->bkp_irqoutpin,
> +			       sizeof(stmfx->bkp_irqoutpin));
> +	if (ret)
> +		return ret;

'\n' here.

> +	ret = regmap_raw_write(stmfx->map, STMFX_REG_IRQ_SRC_EN,
> +			       &stmfx->irq_src, sizeof(stmfx->irq_src));
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int stmfx_suspend(struct device *dev)
> +{
> +	struct stmfx *stmfx = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = stmfx_backup_regs(stmfx);

Don't think you need a separate function for this.  Just move the
regmap_raw_write() commands here.

> +	if (ret) {
> +		dev_err(stmfx->dev, "Registers backup failure\n");
> +		return ret;
> +	}
> +
> +	if (!IS_ERR(stmfx->vdd)) {
> +		ret = regulator_disable(stmfx->vdd);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int stmfx_resume(struct device *dev)
> +{
> +	struct stmfx *stmfx = dev_get_drvdata(dev);
> +	int ret;
> +
> +	if (!IS_ERR(stmfx->vdd)) {
> +		ret = regulator_enable(stmfx->vdd);
> +		if (ret) {
> +			dev_err(stmfx->dev,
> +				"VDD enable failed: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	ret = stmfx_restore_regs(stmfx);

As above.

> +	if (ret) {
> +		dev_err(stmfx->dev, "Registers restoration failure\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(stmfx_dev_pm_ops, stmfx_suspend, stmfx_resume);
> +
> +static const struct of_device_id stmfx_of_match[] = {
> +	{ .compatible = "st,stmfx-0300", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, stmfx_of_match);
> +
> +static struct i2c_driver stmfx_driver = {
> +	.driver = {
> +		.name = "stmfx-core",
> +		.of_match_table = of_match_ptr(stmfx_of_match),
> +		.pm = &stmfx_dev_pm_ops,
> +	},
> +	.probe = stmfx_probe,
> +	.remove = stmfx_remove,
> +};
> +module_i2c_driver(stmfx_driver);
> +
> +MODULE_DESCRIPTION("STMFX core driver");
> +MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@xxxxxx>");
> +MODULE_LICENSE("GPL v2");

[...]

-- 
Lee Jones [æçæ]
Linaro Services Technical Lead
Linaro.org â Open source software for ARM SoCs
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