Re: [PATCH v5 3/7] mfd: Add MFD driver for ATC260x PMICs

On Wed, 13 Jan 2021, Cristian Ciocaltea wrote:

Add initial support for the Actions Semi ATC260x PMICs which integrates
Audio Codec, Power management, Clock generation and GPIO controller
blocks.

For the moment this driver only supports Regulator, Poweroff and Onkey
functionalities for the ATC2603C and ATC2609A chip variants.

Since the PMICs can be accessed using both I2C and SPI buses, the
following driver structure has been adopted:

           -----> atc260x-core.c (Implements core functionalities)
          /
ATC260x --------> atc260x-i2c.c (Implements I2C interface)
          \
           -----> atc260x-spi.c (Implements SPI interface - TODO)

Co-developed-by: Manivannan Sadhasivam <redacted>
Signed-off-by: Manivannan Sadhasivam <redacted>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
---
Changes in v5:
 - None

Changes in v4 - according to Lee's review:
 - Replaced 'regmap_add_irq_chip()' with 'devm' counterpart and dropped
   'atc260x_device_remove()' and 'atc260x_i2c_remove()' functions
 - Moved kerneldoc sections from prototypes to real functions
 - Placed single line entries on one line for mfd_cells[]
 - Several other minor changes

Changes in v3:
 - Fixed the issues reported by Lee's kernel test robot:
   WARNING: modpost: missing MODULE_LICENSE() in drivers/mfd/atc260x-core.o
   >> FATAL: modpost: drivers/mfd/atc260x-i2c: sizeof(struct i2c_device_id)=24 is
      not a modulo of the size of section __mod_i2c__<identifier>_device_table=588.
   >> Fix definition of struct i2c_device_id in mod_devicetable.h
 - Dropped the usage of '.of_compatible' fields in {atc2603c,atc2609a}_mfd_cells[]
 - Added 'Co-developed-by' tag in commit message and dropped [cristian: ...] line

 drivers/mfd/Kconfig                  |  18 ++
 drivers/mfd/Makefile                 |   3 +
 drivers/mfd/atc260x-core.c           | 293 +++++++++++++++++++++++++
 drivers/mfd/atc260x-i2c.c            |  64 ++++++
 include/linux/mfd/atc260x/atc2603c.h | 281 ++++++++++++++++++++++++
 include/linux/mfd/atc260x/atc2609a.h | 308 +++++++++++++++++++++++++++
 include/linux/mfd/atc260x/core.h     |  58 +++++
 7 files changed, 1025 insertions(+)
 create mode 100644 drivers/mfd/atc260x-core.c
 create mode 100644 drivers/mfd/atc260x-i2c.c
 create mode 100644 include/linux/mfd/atc260x/atc2603c.h
 create mode 100644 include/linux/mfd/atc260x/atc2609a.h
 create mode 100644 include/linux/mfd/atc260x/core.h

[...]

+/**
+ * atc260x_device_probe(): Probe a configured ATC260x device
+ *
+ * @atc260x: ATC260x device to probe (must be configured)
+ *
+ * This function lets the ATC260x core register the ATC260x MFD devices
+ * and IRQCHIP. The ATC260x device passed in must be fully configured
+ * with atc260x_match_device, its IRQ set, and regmap created.
+ */
+int atc260x_device_probe(struct atc260x *atc260x)
+{
+	struct device *dev = atc260x->dev;
+	unsigned int chip_rev;
+	int ret;
+
+	if (!atc260x->irq) {
+		dev_err(dev, "No interrupt support\n");
+		return -EINVAL;
+	}
+
+	/* Initialize the hardware */
+	atc260x->dev_init(atc260x);
+
+	ret = regmap_read(atc260x->regmap, atc260x->rev_reg, &chip_rev);
+	if (ret) {
+		dev_err(dev, "Failed to get chip revision\n");
+		return ret;
+	}
+
+	if (chip_rev > 31) {

Nit: If you have to respin this, please define this magic number.

+		dev_err(dev, "Unknown chip revision: %u\n", chip_rev);
+		return -EINVAL;
+	}
+
+	atc260x->ic_ver = __ffs(chip_rev + 1U);
+
+	dev_info(dev, "Detected chip type %s rev.%c\n",
+		 atc260x->type_name, 'A' + atc260x->ic_ver);
+
+	ret = devm_regmap_add_irq_chip(dev, atc260x->regmap, atc260x->irq, IRQF_ONESHOT,
+				       -1, atc260x->regmap_irq_chip, &atc260x->irq_data);
+	if (ret) {
+		dev_err(dev, "Failed to add IRQ chip: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				   atc260x->cells, atc260x->nr_cells, NULL, 0,
+				   regmap_irq_get_domain(atc260x->irq_data));
+	if (ret) {
+		dev_err(dev, "Failed to add child devices: %d\n", ret);
+		regmap_del_irq_chip(atc260x->irq, atc260x->irq_data);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atc260x_device_probe);

[...]

+static struct i2c_driver atc260x_i2c_driver = {
+	.driver = {
+		.name	= "atc260x",
+		.of_match_table	= of_match_ptr(atc260x_i2c_of_match),
+	},
+	.probe		= atc260x_i2c_probe,
+};

Nit: These spacings/line-ups just look odd.

Please stick to one ' ' after the '='.

+module_i2c_driver(atc260x_i2c_driver);

[...]

+struct atc260x {
+	struct device *dev;
+
+	struct regmap *regmap;
+	const struct regmap_irq_chip *regmap_irq_chip;
+	struct regmap_irq_chip_data *irq_data;
+
+	struct mutex *regmap_mutex;	/* mutex for custom regmap locking */
+
+	const struct mfd_cell *cells;
+	int nr_cells;
+	int irq;
+
+	enum atc260x_type ic_type;
+	enum atc260x_ver ic_ver;
+	const char *type_name;
+	unsigned int rev_reg;
+
+	int (*dev_init)(struct atc260x *atc260x);

Ah, I didn't see this before.

Call-backs of this nature are the devil.  Please populate a struct
with the differentiating register addresses/values instead and always
call a generic deivce_init().

+};
+
+struct regmap_config;
+
+int atc260x_match_device(struct atc260x *atc260x, struct regmap_config *regmap_cfg);
+int atc260x_device_probe(struct atc260x *atc260x);
+
+#endif /* __LINUX_MFD_ATC260X_CORE_H */

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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