[1/2] dt-bindings: mfd: Add Spreadtrum SC27xx PMIC documentation

Message ID 73965e7fb34d6a96529589cdf48e54e95ed666b8.1507723345.git.baolin.wang@spreadtrum.com
State Superseded
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  • [1/2] dt-bindings: mfd: Add Spreadtrum SC27xx PMIC documentation
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Commit Message

Baolin Wang Oct. 11, 2017, 12:17 p.m.
This patch adds the binding documentation for Spreadtrum SC27xx series
PMIC device.

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
---
 .../devicetree/bindings/mfd/sprd,sc27xx-pmic.txt   |   23 ++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt

Comments

Lee Jones Oct. 13, 2017, 9:07 a.m. | #1
On Wed, 11 Oct 2017, Baolin Wang wrote:

> This patch adds the binding documentation for Spreadtrum SC27xx series
> PMIC device.
> 
> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> ---
>  .../devicetree/bindings/mfd/sprd,sc27xx-pmic.txt   |   23 ++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
> 
> diff --git a/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
> new file mode 100644
> index 0000000..333c818
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
> @@ -0,0 +1,23 @@
> +Spreadtrum SC27xx Power Management Integrated Circuit (PMIC)

More info please.

What does the ship do and what other devices are available.

> +Required properties:
> +- compatible: Should be "sprd,sc2731".
> +- reg: SPI chip select.

Really?  Not an address?

What is the range?

> +- spi-max-frequency: Typically set to 26000000.
> +- interrupts: The interrupt line the device is connected to.
> +- interrupt-controller: Marks the device node as an interrupt controller.
> +- #interrupt-cells: The number of cells to describe an PMIC IRQ, should be 2.

What if it's not 2?  Will it still work?

> +- #address-cells: Child device offset number of cells, should be 1.

Same.

> +- #size-cells: Child device size number of cells, should be 0.

Same.

> +
> +Example:
> +pmic: pmic@0 {

What other nodes are you referencing this one from?

> +	compatible = "sprd,sc2731";
> +	reg = <0>;
> +	spi-max-frequency = <26000000>;
> +	interrupts = <GIC_SPI 31 IRQ_TYPE_LEVEL_HIGH>;
> +	interrupt-controller;
> +	#interrupt-cells = <2>;
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +};
Lee Jones Oct. 13, 2017, 9:26 a.m. | #2
On Wed, 11 Oct 2017, Baolin Wang wrote:

> This patch adds support for Spreadtrum SC27xx series PMIC MFD core, and It
> provides communication through the SPI interfaces. The SC27xx series PMICs
> contains the following 6 major components:
> - DCDCs
> - LDOs
> - Battery management system
> - Audio codec
> - User interface function, such as indicator, flash LED
> - IC level function, such as power on/off, type-c
> 
> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> ---
>  drivers/mfd/Kconfig           |   10 ++
>  drivers/mfd/Makefile          |    1 +
>  drivers/mfd/sprd-sc27xx-spi.c |  273 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 284 insertions(+)
>  create mode 100644 drivers/mfd/sprd-sc27xx-spi.c
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index fc5e4fe..4753cd5 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1057,6 +1057,16 @@ config MFD_SMSC
>          To compile this driver as a module, choose M here: the
>          module will be called smsc.
>  
> +config MFD_SC27XX_PMIC
> +	tristate "Spreadtrum SC27xx PMICs"
> +	depends on ARCH_SPRD || COMPILE_TEST
> +	depends on SPI_MASTER
> +	select MFD_CORE
> +	select REGMAP_SPI
> +	select REGMAP_IRQ
> +	help
> +	  This enables support for the Spreadtrum SC27xx PMICs.
> +
>  config ABX500_CORE
>  	bool "ST-Ericsson ABX500 Mixed Signal Circuit register functions"
>  	default y if ARCH_U300 || ARCH_U8500 || COMPILE_TEST
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index c3d0a1b..a377e0f 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -226,3 +226,4 @@ obj-$(CONFIG_MFD_SUN4I_GPADC)	+= sun4i-gpadc.o
>  obj-$(CONFIG_MFD_STM32_LPTIMER)	+= stm32-lptimer.o
>  obj-$(CONFIG_MFD_STM32_TIMERS) 	+= stm32-timers.o
>  obj-$(CONFIG_MFD_MXS_LRADC)     += mxs-lradc.o
> +obj-$(CONFIG_MFD_SC27XX_PMIC)	+= sprd-sc27xx-spi.o
> diff --git a/drivers/mfd/sprd-sc27xx-spi.c b/drivers/mfd/sprd-sc27xx-spi.c
> new file mode 100644
> index 0000000..2b3f2bc
> --- /dev/null
> +++ b/drivers/mfd/sprd-sc27xx-spi.c
> @@ -0,0 +1,273 @@
> +/*
> + * Copyright (C) 2017 Spreadtrum Communications Inc.
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * 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/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mfd/core.h>
> +#include <linux/of_device.h>
> +#include <linux/spi/spi.h>
> +#include <linux/regmap.h>

Alphabetical.

> +#define SPRD_PMIC_INT_MASK_STATUS	0x0
> +#define SPRD_PMIC_INT_RAW_STATU		0x4
> +#define SPRD_PMIC_INT_EN		0x8
> +
> +struct sprd_pmic {
> +	struct regmap *regmap;
> +	struct device *dev;
> +	struct regmap_irq *irqs;
> +	struct regmap_irq_chip irq_chip;
> +	struct regmap_irq_chip_data *irq_data;
> +	int irq;
> +};
> +
> +struct sprd_pmic_data {
> +	u32 irq_base;
> +	u32 num_irqs;
> +};
> +
> +static const struct sprd_pmic_data sc2731_data = {
> +	.irq_base = 0x140,
> +	.num_irqs = 16,
> +};
> +
> +static const struct mfd_cell sprd_pmic_devs[] = {
> +	{
> +		.name = "sc27xx-wdt",
> +		.of_compatible = "sprd,sc27xx-wdt",
> +	},
> +	{

Nit: You can save a few lines here by using the format:

> +	}, {

> +		.name = "sc27xx-rtc",
> +		.of_compatible = "sprd,sc27xx-rtc",
> +	},
> +	{
> +		.name = "sc27xx-charger",
> +		.of_compatible = "sprd,sc27xx-charger",
> +	},
> +	{
> +		.name = "sc27xx-chg-timer",
> +		.of_compatible = "sprd,sc27xx-chg-timer",
> +	},
> +	{
> +		.name = "sc27xx-fast-chg",
> +		.of_compatible = "sprd,sc27xx-fast-chg",
> +	},
> +	{
> +		.name = "sc27xx-chg-wdt",
> +		.of_compatible = "sprd,sc27xx-chg-wdt",
> +	},
> +	{
> +		.name = "sc27xx-typec",
> +		.of_compatible = "sprd,sc27xx-typec",
> +	},
> +	{
> +		.name = "sc27xx-flash",
> +		.of_compatible = "sprd,sc27xx-flash",
> +	},
> +	{
> +		.name = "sc27xx-eic",
> +		.of_compatible = "sprd,sc27xx-eic",
> +	},
> +	{
> +		.name = "sc27xx-efuse",
> +		.of_compatible = "sprd,sc27xx-efuse",
> +	},
> +	{
> +		.name = "sc27xx-thermal",
> +		.of_compatible = "sprd,sc27xx-thermal",
> +	},
> +	{
> +		.name = "sc27xx-adc",
> +		.of_compatible = "sprd,sc27xx-adc",
> +	},
> +	{
> +		.name = "sc27xx-audio-codec",
> +		.of_compatible = "sprd,sc27xx-audio-codec",
> +	},
> +	{
> +		.name = "sc27xx-regulator",
> +		.of_compatible = "sprd,sc27xx-regulator",
> +	},
> +	{
> +		.name = "sc27xx-vibrator",
> +		.of_compatible = "sprd,sc27xx-vibrator",
> +	},
> +	{
> +		.name = "sc27xx-keypad-led",
> +		.of_compatible = "sprd,sc27xx-keypad-led",
> +	},
> +	{
> +		.name = "sc27xx-bltc",
> +		.of_compatible = "sprd,sc27xx-bltc",
> +	},
> +	{
> +		.name = "sc27xx-fgu",
> +		.of_compatible = "sprd,sc27xx-fgu",
> +	},
> +	{
> +		.name = "sc27xx-7sreset",
> +		.of_compatible = "sprd,sc27xx-7sreset",
> +	},
> +	{
> +		.name = "sc27xx-poweroff",
> +		.of_compatible = "sprd,sc27xx-poweroff",
> +	},
> +};
> +
> +static int sprd_pmic_spi_write(void *context, const void *data, size_t count)
> +{
> +	struct device *dev = context;
> +	struct spi_device *spi = to_spi_device(dev);
> +
> +	return spi_write(spi, data, count);
> +}
> +
> +static int sprd_pmic_spi_read(void *context,
> +			      const void *reg, size_t reg_size,
> +			      void *val, size_t val_size)
> +{
> +	struct device *dev = context;
> +	struct spi_device *spi = to_spi_device(dev);
> +	u32 rx_buf[2] = { 0 };
> +	int ret;
> +
> +	rx_buf[0] = *(u32 *)reg;
> +	ret = spi_read(spi, rx_buf, 1);
> +	if (ret < 0)
> +		return ret;
> +
> +	memcpy(val, rx_buf, val_size);

This looks like you're asking for trouble.

What if val_size > sizeof(rx_buf)?

You should probably check for that.

> +	return 0;
> +}
> +
> +static struct regmap_bus sprd_pmic_regmap = {
> +	.write = sprd_pmic_spi_write,
> +	.read = sprd_pmic_spi_read,
> +	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +};
> +
> +static const struct regmap_config sprd_pmic_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.max_register = 0xffff,
> +};
> +
> +static int sprd_pmic_probe(struct spi_device *spi)
> +{
> +	struct sprd_pmic *sprd_pmic;
> +	const struct sprd_pmic_data *data;
> +	int ret, i;
> +
> +	data = of_device_get_match_data(&spi->dev);
> +	if (!data) {
> +		dev_err(&spi->dev, "No matching driver data found\n");
> +		return -EINVAL;
> +	}
> +
> +	sprd_pmic = devm_kzalloc(&spi->dev, sizeof(*sprd_pmic), GFP_KERNEL);
> +	if (!sprd_pmic)
> +		return -ENOMEM;
> +
> +	sprd_pmic->regmap = devm_regmap_init(&spi->dev, &sprd_pmic_regmap,
> +					     &spi->dev, &sprd_pmic_config);
> +	if (IS_ERR(sprd_pmic->regmap)) {
> +		ret = PTR_ERR(sprd_pmic->regmap);
> +		dev_err(&spi->dev, "Failed to allocate register map %d\n", ret);
> +		return ret;
> +	}
> +
> +	spi_set_drvdata(spi, sprd_pmic);
> +	sprd_pmic->dev = &spi->dev;
> +	sprd_pmic->irq = spi->irq;
> +
> +	sprd_pmic->irq_chip.name = dev_name(&spi->dev);
> +	sprd_pmic->irq_chip.status_base =
> +		data->irq_base + SPRD_PMIC_INT_MASK_STATUS;
> +	sprd_pmic->irq_chip.mask_base = data->irq_base + SPRD_PMIC_INT_EN;
> +	sprd_pmic->irq_chip.ack_base = 0;
> +	sprd_pmic->irq_chip.num_regs = 1;
> +	sprd_pmic->irq_chip.num_irqs = data->num_irqs;
> +	sprd_pmic->irq_chip.mask_invert = true;
> +
> +	sprd_pmic->irqs = devm_kzalloc(&spi->dev, sizeof(struct regmap_irq) *
> +				       data->num_irqs, GFP_KERNEL);
> +	if (!sprd_pmic->irqs)
> +		return -ENOMEM;
> +
> +	sprd_pmic->irq_chip.irqs = sprd_pmic->irqs;
> +	for (i = 0; i < data->num_irqs; i++) {
> +		sprd_pmic->irqs[i].reg_offset = i / data->num_irqs;
> +		sprd_pmic->irqs[i].mask = BIT(i % data->num_irqs);
> +	}

Why don't you do this live, instead of pre-calculating?

> +	ret = devm_regmap_add_irq_chip(&spi->dev, sprd_pmic->regmap,
> +				       sprd_pmic->irq,
> +				       IRQF_ONESHOT | IRQF_NO_SUSPEND, 0,
> +				       &sprd_pmic->irq_chip,
> +				       &sprd_pmic->irq_data);
> +	if (ret) {
> +		dev_err(&spi->dev, "Failed to add PMIC irq chip %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = mfd_add_devices(&spi->dev, PLATFORM_DEVID_AUTO, sprd_pmic_devs,
> +			      ARRAY_SIZE(sprd_pmic_devs), NULL, 0,
> +			      regmap_irq_get_domain(sprd_pmic->irq_data));
> +	if (ret) {
> +		dev_err(&spi->dev, "Failed to register device %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sprd_pmic_remove(struct spi_device *spi)
> +{
> +	mfd_remove_devices(&spi->dev);

'\n' here please.

> +	return 0;
> +}
> +
> +static const struct of_device_id sprd_pmic_match[] = {
> +	{ .compatible = "sprd,sc2731", .data = &sc2731_data },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, sprd_pmic_match);
> +
> +static struct spi_driver sprd_pmic_driver = {
> +	.driver = {
> +		   .name = "sc27xx-pmic",
> +		   .bus = &spi_bus_type,
> +		   .of_match_table = sprd_pmic_match,

Odd tabbing here.  Should be 8 chars.

> +	},
> +	.probe = sprd_pmic_probe,
> +	.remove = sprd_pmic_remove,
> +};
> +
> +static int __init sprd_pmic_init(void)
> +{
> +	return spi_register_driver(&sprd_pmic_driver);
> +}
> +subsys_initcall(sprd_pmic_init);
> +
> +static void __exit sprd_pmic_exit(void)
> +{
> +	spi_unregister_driver(&sprd_pmic_driver);
> +}
> +module_exit(sprd_pmic_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("SPI support for SC27xx PMICs");
> +MODULE_AUTHOR("Baolin Wang <baolin.wang@spreadtrum.com>");
Baolin Wang Oct. 13, 2017, 9:28 a.m. | #3
Hi Lee,

On 13 October 2017 at 17:07, Lee Jones <lee.jones@linaro.org> wrote:
> On Wed, 11 Oct 2017, Baolin Wang wrote:
>
>> This patch adds the binding documentation for Spreadtrum SC27xx series
>> PMIC device.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
>> ---
>>  .../devicetree/bindings/mfd/sprd,sc27xx-pmic.txt   |   23 ++++++++++++++++++++
>>  1 file changed, 23 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
>> new file mode 100644
>> index 0000000..333c818
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
>> @@ -0,0 +1,23 @@
>> +Spreadtrum SC27xx Power Management Integrated Circuit (PMIC)
>
> More info please.
>
> What does the ship do and what other devices are available.

OK. I will add more information in next version.

>
>> +Required properties:
>> +- compatible: Should be "sprd,sc2731".
>> +- reg: SPI chip select.
>
> Really?  Not an address?

Yes, it should be device address.

>
> What is the range?
>
>> +- spi-max-frequency: Typically set to 26000000.
>> +- interrupts: The interrupt line the device is connected to.
>> +- interrupt-controller: Marks the device node as an interrupt controller.
>> +- #interrupt-cells: The number of cells to describe an PMIC IRQ, should be 2.
>
> What if it's not 2?  Will it still work?

Must be 2, if not it can not work well. Will update in next version.

>
>> +- #address-cells: Child device offset number of cells, should be 1.
>
> Same.

OK.

>
>> +- #size-cells: Child device size number of cells, should be 0.
>
> Same.

OK.

>
>> +
>> +Example:
>> +pmic: pmic@0 {
>
> What other nodes are you referencing this one from?

This node should be under our ADI/SPI master device node, as one SPI
device. I will add the SPI master node in next version. Very
appreciated for your comments.
Baolin Wang Oct. 13, 2017, 9:37 a.m. | #4
Hi Lee,

On 13 October 2017 at 17:26, Lee Jones <lee.jones@linaro.org> wrote:
> On Wed, 11 Oct 2017, Baolin Wang wrote:
>
>> This patch adds support for Spreadtrum SC27xx series PMIC MFD core, and It
>> provides communication through the SPI interfaces. The SC27xx series PMICs
>> contains the following 6 major components:
>> - DCDCs
>> - LDOs
>> - Battery management system
>> - Audio codec
>> - User interface function, such as indicator, flash LED
>> - IC level function, such as power on/off, type-c
>>
>> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
>> ---
>>  drivers/mfd/Kconfig           |   10 ++
>>  drivers/mfd/Makefile          |    1 +
>>  drivers/mfd/sprd-sc27xx-spi.c |  273 +++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 284 insertions(+)
>>  create mode 100644 drivers/mfd/sprd-sc27xx-spi.c
>>
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index fc5e4fe..4753cd5 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -1057,6 +1057,16 @@ config MFD_SMSC
>>          To compile this driver as a module, choose M here: the
>>          module will be called smsc.
>>
>> +config MFD_SC27XX_PMIC
>> +     tristate "Spreadtrum SC27xx PMICs"
>> +     depends on ARCH_SPRD || COMPILE_TEST
>> +     depends on SPI_MASTER
>> +     select MFD_CORE
>> +     select REGMAP_SPI
>> +     select REGMAP_IRQ
>> +     help
>> +       This enables support for the Spreadtrum SC27xx PMICs.
>> +
>>  config ABX500_CORE
>>       bool "ST-Ericsson ABX500 Mixed Signal Circuit register functions"
>>       default y if ARCH_U300 || ARCH_U8500 || COMPILE_TEST
>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>> index c3d0a1b..a377e0f 100644
>> --- a/drivers/mfd/Makefile
>> +++ b/drivers/mfd/Makefile
>> @@ -226,3 +226,4 @@ obj-$(CONFIG_MFD_SUN4I_GPADC)     += sun4i-gpadc.o
>>  obj-$(CONFIG_MFD_STM32_LPTIMER)      += stm32-lptimer.o
>>  obj-$(CONFIG_MFD_STM32_TIMERS)       += stm32-timers.o
>>  obj-$(CONFIG_MFD_MXS_LRADC)     += mxs-lradc.o
>> +obj-$(CONFIG_MFD_SC27XX_PMIC)        += sprd-sc27xx-spi.o
>> diff --git a/drivers/mfd/sprd-sc27xx-spi.c b/drivers/mfd/sprd-sc27xx-spi.c
>> new file mode 100644
>> index 0000000..2b3f2bc
>> --- /dev/null
>> +++ b/drivers/mfd/sprd-sc27xx-spi.c
>> @@ -0,0 +1,273 @@
>> +/*
>> + * Copyright (C) 2017 Spreadtrum Communications Inc.
>> + *
>> + * This software is licensed under the terms of the GNU General Public
>> + * License version 2, as published by the Free Software Foundation, and
>> + * may be copied, distributed, and modified under those terms.
>> + *
>> + * 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/interrupt.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/mfd/core.h>
>> +#include <linux/of_device.h>
>> +#include <linux/spi/spi.h>
>> +#include <linux/regmap.h>
>
> Alphabetical.

Ah, sorry. Will fix in next version.

>
>> +#define SPRD_PMIC_INT_MASK_STATUS    0x0
>> +#define SPRD_PMIC_INT_RAW_STATU              0x4
>> +#define SPRD_PMIC_INT_EN             0x8
>> +
>> +struct sprd_pmic {
>> +     struct regmap *regmap;
>> +     struct device *dev;
>> +     struct regmap_irq *irqs;
>> +     struct regmap_irq_chip irq_chip;
>> +     struct regmap_irq_chip_data *irq_data;
>> +     int irq;
>> +};
>> +
>> +struct sprd_pmic_data {
>> +     u32 irq_base;
>> +     u32 num_irqs;
>> +};
>> +
>> +static const struct sprd_pmic_data sc2731_data = {
>> +     .irq_base = 0x140,
>> +     .num_irqs = 16,
>> +};
>> +
>> +static const struct mfd_cell sprd_pmic_devs[] = {
>> +     {
>> +             .name = "sc27xx-wdt",
>> +             .of_compatible = "sprd,sc27xx-wdt",
>> +     },
>> +     {
>
> Nit: You can save a few lines here by using the format:

OK.

>
>> +     }, {
>
>> +             .name = "sc27xx-rtc",
>> +             .of_compatible = "sprd,sc27xx-rtc",
>> +     },
>> +     {
>> +             .name = "sc27xx-charger",
>> +             .of_compatible = "sprd,sc27xx-charger",
>> +     },
>> +     {
>> +             .name = "sc27xx-chg-timer",
>> +             .of_compatible = "sprd,sc27xx-chg-timer",
>> +     },
>> +     {
>> +             .name = "sc27xx-fast-chg",
>> +             .of_compatible = "sprd,sc27xx-fast-chg",
>> +     },
>> +     {
>> +             .name = "sc27xx-chg-wdt",
>> +             .of_compatible = "sprd,sc27xx-chg-wdt",
>> +     },
>> +     {
>> +             .name = "sc27xx-typec",
>> +             .of_compatible = "sprd,sc27xx-typec",
>> +     },
>> +     {
>> +             .name = "sc27xx-flash",
>> +             .of_compatible = "sprd,sc27xx-flash",
>> +     },
>> +     {
>> +             .name = "sc27xx-eic",
>> +             .of_compatible = "sprd,sc27xx-eic",
>> +     },
>> +     {
>> +             .name = "sc27xx-efuse",
>> +             .of_compatible = "sprd,sc27xx-efuse",
>> +     },
>> +     {
>> +             .name = "sc27xx-thermal",
>> +             .of_compatible = "sprd,sc27xx-thermal",
>> +     },
>> +     {
>> +             .name = "sc27xx-adc",
>> +             .of_compatible = "sprd,sc27xx-adc",
>> +     },
>> +     {
>> +             .name = "sc27xx-audio-codec",
>> +             .of_compatible = "sprd,sc27xx-audio-codec",
>> +     },
>> +     {
>> +             .name = "sc27xx-regulator",
>> +             .of_compatible = "sprd,sc27xx-regulator",
>> +     },
>> +     {
>> +             .name = "sc27xx-vibrator",
>> +             .of_compatible = "sprd,sc27xx-vibrator",
>> +     },
>> +     {
>> +             .name = "sc27xx-keypad-led",
>> +             .of_compatible = "sprd,sc27xx-keypad-led",
>> +     },
>> +     {
>> +             .name = "sc27xx-bltc",
>> +             .of_compatible = "sprd,sc27xx-bltc",
>> +     },
>> +     {
>> +             .name = "sc27xx-fgu",
>> +             .of_compatible = "sprd,sc27xx-fgu",
>> +     },
>> +     {
>> +             .name = "sc27xx-7sreset",
>> +             .of_compatible = "sprd,sc27xx-7sreset",
>> +     },
>> +     {
>> +             .name = "sc27xx-poweroff",
>> +             .of_compatible = "sprd,sc27xx-poweroff",
>> +     },
>> +};
>> +
>> +static int sprd_pmic_spi_write(void *context, const void *data, size_t count)
>> +{
>> +     struct device *dev = context;
>> +     struct spi_device *spi = to_spi_device(dev);
>> +
>> +     return spi_write(spi, data, count);
>> +}
>> +
>> +static int sprd_pmic_spi_read(void *context,
>> +                           const void *reg, size_t reg_size,
>> +                           void *val, size_t val_size)
>> +{
>> +     struct device *dev = context;
>> +     struct spi_device *spi = to_spi_device(dev);
>> +     u32 rx_buf[2] = { 0 };
>> +     int ret;
>> +
>> +     rx_buf[0] = *(u32 *)reg;
>> +     ret = spi_read(spi, rx_buf, 1);
>> +     if (ret < 0)
>> +             return ret;
>> +
>> +     memcpy(val, rx_buf, val_size);
>
> This looks like you're asking for trouble.
>
> What if val_size > sizeof(rx_buf)?
>
> You should probably check for that.

Since we always read one register every time, which means the reg_size
and val_size are always 4. But it will be more helpful to check
incorrect parameters by adding one check here.

>
>> +     return 0;
>> +}
>> +
>> +static struct regmap_bus sprd_pmic_regmap = {
>> +     .write = sprd_pmic_spi_write,
>> +     .read = sprd_pmic_spi_read,
>> +     .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
>> +     .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
>> +};
>> +
>> +static const struct regmap_config sprd_pmic_config = {
>> +     .reg_bits = 32,
>> +     .val_bits = 32,
>> +     .reg_stride = 4,
>> +     .max_register = 0xffff,
>> +};
>> +
>> +static int sprd_pmic_probe(struct spi_device *spi)
>> +{
>> +     struct sprd_pmic *sprd_pmic;
>> +     const struct sprd_pmic_data *data;
>> +     int ret, i;
>> +
>> +     data = of_device_get_match_data(&spi->dev);
>> +     if (!data) {
>> +             dev_err(&spi->dev, "No matching driver data found\n");
>> +             return -EINVAL;
>> +     }
>> +
>> +     sprd_pmic = devm_kzalloc(&spi->dev, sizeof(*sprd_pmic), GFP_KERNEL);
>> +     if (!sprd_pmic)
>> +             return -ENOMEM;
>> +
>> +     sprd_pmic->regmap = devm_regmap_init(&spi->dev, &sprd_pmic_regmap,
>> +                                          &spi->dev, &sprd_pmic_config);
>> +     if (IS_ERR(sprd_pmic->regmap)) {
>> +             ret = PTR_ERR(sprd_pmic->regmap);
>> +             dev_err(&spi->dev, "Failed to allocate register map %d\n", ret);
>> +             return ret;
>> +     }
>> +
>> +     spi_set_drvdata(spi, sprd_pmic);
>> +     sprd_pmic->dev = &spi->dev;
>> +     sprd_pmic->irq = spi->irq;
>> +
>> +     sprd_pmic->irq_chip.name = dev_name(&spi->dev);
>> +     sprd_pmic->irq_chip.status_base =
>> +             data->irq_base + SPRD_PMIC_INT_MASK_STATUS;
>> +     sprd_pmic->irq_chip.mask_base = data->irq_base + SPRD_PMIC_INT_EN;
>> +     sprd_pmic->irq_chip.ack_base = 0;
>> +     sprd_pmic->irq_chip.num_regs = 1;
>> +     sprd_pmic->irq_chip.num_irqs = data->num_irqs;
>> +     sprd_pmic->irq_chip.mask_invert = true;
>> +
>> +     sprd_pmic->irqs = devm_kzalloc(&spi->dev, sizeof(struct regmap_irq) *
>> +                                    data->num_irqs, GFP_KERNEL);
>> +     if (!sprd_pmic->irqs)
>> +             return -ENOMEM;
>> +
>> +     sprd_pmic->irq_chip.irqs = sprd_pmic->irqs;
>> +     for (i = 0; i < data->num_irqs; i++) {
>> +             sprd_pmic->irqs[i].reg_offset = i / data->num_irqs;
>> +             sprd_pmic->irqs[i].mask = BIT(i % data->num_irqs);
>> +     }
>
> Why don't you do this live, instead of pre-calculating?

Since the SC27xx series PMICs have different interrupts number (such
as SC2731 has 16 interrupts and SC2720 has 6 interrupts).

>
>> +     ret = devm_regmap_add_irq_chip(&spi->dev, sprd_pmic->regmap,
>> +                                    sprd_pmic->irq,
>> +                                    IRQF_ONESHOT | IRQF_NO_SUSPEND, 0,
>> +                                    &sprd_pmic->irq_chip,
>> +                                    &sprd_pmic->irq_data);
>> +     if (ret) {
>> +             dev_err(&spi->dev, "Failed to add PMIC irq chip %d\n", ret);
>> +             return ret;
>> +     }
>> +
>> +     ret = mfd_add_devices(&spi->dev, PLATFORM_DEVID_AUTO, sprd_pmic_devs,
>> +                           ARRAY_SIZE(sprd_pmic_devs), NULL, 0,
>> +                           regmap_irq_get_domain(sprd_pmic->irq_data));
>> +     if (ret) {
>> +             dev_err(&spi->dev, "Failed to register device %d\n", ret);
>> +             return ret;
>> +     }
>> +
>> +     return 0;
>> +}
>> +
>> +static int sprd_pmic_remove(struct spi_device *spi)
>> +{
>> +     mfd_remove_devices(&spi->dev);
>
> '\n' here please.

OK.

>
>> +     return 0;
>> +}
>> +
>> +static const struct of_device_id sprd_pmic_match[] = {
>> +     { .compatible = "sprd,sc2731", .data = &sc2731_data },
>> +     {},
>> +};
>> +MODULE_DEVICE_TABLE(of, sprd_pmic_match);
>> +
>> +static struct spi_driver sprd_pmic_driver = {
>> +     .driver = {
>> +                .name = "sc27xx-pmic",
>> +                .bus = &spi_bus_type,
>> +                .of_match_table = sprd_pmic_match,
>
> Odd tabbing here.  Should be 8 chars.

I will fix this mistake in next version. Thanks for your comments.
Lee Jones Oct. 13, 2017, 9:55 a.m. | #5
On Fri, 13 Oct 2017, Baolin Wang wrote:
> On 13 October 2017 at 17:07, Lee Jones <lee.jones@linaro.org> wrote:
> > On Wed, 11 Oct 2017, Baolin Wang wrote:
> >
> >> This patch adds the binding documentation for Spreadtrum SC27xx series
> >> PMIC device.
> >>
> >> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> >> ---
> >>  .../devicetree/bindings/mfd/sprd,sc27xx-pmic.txt   |   23 ++++++++++++++++++++
> >>  1 file changed, 23 insertions(+)
> >>  create mode 100644 Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
> >> new file mode 100644
> >> index 0000000..333c818
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
> >> @@ -0,0 +1,23 @@
> >> +Spreadtrum SC27xx Power Management Integrated Circuit (PMIC)
> >
> > More info please.
> >
> > What does the ship do and what other devices are available.
> 
> OK. I will add more information in next version.
> 
> >
> >> +Required properties:
> >> +- compatible: Should be "sprd,sc2731".
> >> +- reg: SPI chip select.
> >
> > Really?  Not an address?
> 
> Yes, it should be device address.
> 
> >
> > What is the range?
> >
> >> +- spi-max-frequency: Typically set to 26000000.
> >> +- interrupts: The interrupt line the device is connected to.
> >> +- interrupt-controller: Marks the device node as an interrupt controller.
> >> +- #interrupt-cells: The number of cells to describe an PMIC IRQ, should be 2.
> >
> > What if it's not 2?  Will it still work?
> 
> Must be 2, if not it can not work well. Will update in next version.
> 
> >
> >> +- #address-cells: Child device offset number of cells, should be 1.
> >
> > Same.
> 
> OK.
> 
> >
> >> +- #size-cells: Child device size number of cells, should be 0.
> >
> > Same.
> 
> OK.
> 
> >
> >> +
> >> +Example:
> >> +pmic: pmic@0 {
> >
> > What other nodes are you referencing this one from?
> 
> This node should be under our ADI/SPI master device node, as one SPI
> device. I will add the SPI master node in next version. Very
> appreciated for your comments.

Sorry, what I'm getting at is; is the 'pmic:' label really required?
Lee Jones Oct. 13, 2017, 10:13 a.m. | #6
On Fri, 13 Oct 2017, Baolin Wang wrote:
> On 13 October 2017 at 17:26, Lee Jones <lee.jones@linaro.org> wrote:
> > On Wed, 11 Oct 2017, Baolin Wang wrote:
> >
> >> This patch adds support for Spreadtrum SC27xx series PMIC MFD core, and It
> >> provides communication through the SPI interfaces. The SC27xx series PMICs
> >> contains the following 6 major components:
> >> - DCDCs
> >> - LDOs
> >> - Battery management system
> >> - Audio codec
> >> - User interface function, such as indicator, flash LED
> >> - IC level function, such as power on/off, type-c
> >>
> >> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> >> ---
> >>  drivers/mfd/Kconfig           |   10 ++
> >>  drivers/mfd/Makefile          |    1 +
> >>  drivers/mfd/sprd-sc27xx-spi.c |  273 +++++++++++++++++++++++++++++++++++++++++
> >>  3 files changed, 284 insertions(+)
> >>  create mode 100644 drivers/mfd/sprd-sc27xx-spi.c
> >>
> >> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> >> index fc5e4fe..4753cd5 100644
> >> --- a/drivers/mfd/Kconfig
> >> +++ b/drivers/mfd/Kconfig
> >> @@ -1057,6 +1057,16 @@ config MFD_SMSC
> >>          To compile this driver as a module, choose M here: the
> >>          module will be called smsc.
> >>
> >> +config MFD_SC27XX_PMIC
> >> +     tristate "Spreadtrum SC27xx PMICs"
> >> +     depends on ARCH_SPRD || COMPILE_TEST
> >> +     depends on SPI_MASTER
> >> +     select MFD_CORE
> >> +     select REGMAP_SPI
> >> +     select REGMAP_IRQ
> >> +     help
> >> +       This enables support for the Spreadtrum SC27xx PMICs.
> >> +
> >>  config ABX500_CORE
> >>       bool "ST-Ericsson ABX500 Mixed Signal Circuit register functions"
> >>       default y if ARCH_U300 || ARCH_U8500 || COMPILE_TEST
> >> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> >> index c3d0a1b..a377e0f 100644
> >> --- a/drivers/mfd/Makefile
> >> +++ b/drivers/mfd/Makefile
> >> @@ -226,3 +226,4 @@ obj-$(CONFIG_MFD_SUN4I_GPADC)     += sun4i-gpadc.o
> >>  obj-$(CONFIG_MFD_STM32_LPTIMER)      += stm32-lptimer.o
> >>  obj-$(CONFIG_MFD_STM32_TIMERS)       += stm32-timers.o
> >>  obj-$(CONFIG_MFD_MXS_LRADC)     += mxs-lradc.o
> >> +obj-$(CONFIG_MFD_SC27XX_PMIC)        += sprd-sc27xx-spi.o
> >> diff --git a/drivers/mfd/sprd-sc27xx-spi.c b/drivers/mfd/sprd-sc27xx-spi.c
> >> new file mode 100644
> >> index 0000000..2b3f2bc
> >> --- /dev/null
> >> +++ b/drivers/mfd/sprd-sc27xx-spi.c
> >> @@ -0,0 +1,273 @@
> >> +/*
> >> + * Copyright (C) 2017 Spreadtrum Communications Inc.
> >> + *
> >> + * This software is licensed under the terms of the GNU General Public
> >> + * License version 2, as published by the Free Software Foundation, and
> >> + * may be copied, distributed, and modified under those terms.
> >> + *
> >> + * 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.
> >> + */

[...]

> >> +static int sprd_pmic_spi_read(void *context,
> >> +                           const void *reg, size_t reg_size,
> >> +                           void *val, size_t val_size)
> >> +{
> >> +     struct device *dev = context;
> >> +     struct spi_device *spi = to_spi_device(dev);
> >> +     u32 rx_buf[2] = { 0 };
> >> +     int ret;
> >> +
> >> +     rx_buf[0] = *(u32 *)reg;
> >> +     ret = spi_read(spi, rx_buf, 1);
> >> +     if (ret < 0)
> >> +             return ret;
> >> +
> >> +     memcpy(val, rx_buf, val_size);
> >
> > This looks like you're asking for trouble.
> >
> > What if val_size > sizeof(rx_buf)?
> >
> > You should probably check for that.
> 
> Since we always read one register every time, which means the reg_size
> and val_size are always 4. But it will be more helpful to check
> incorrect parameters by adding one check here.
> 
> >
> >> +     return 0;
> >> +}
> >> +
> >> +static struct regmap_bus sprd_pmic_regmap = {
> >> +     .write = sprd_pmic_spi_write,
> >> +     .read = sprd_pmic_spi_read,
> >> +     .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
> >> +     .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
> >> +};
> >> +
> >> +static const struct regmap_config sprd_pmic_config = {
> >> +     .reg_bits = 32,
> >> +     .val_bits = 32,
> >> +     .reg_stride = 4,
> >> +     .max_register = 0xffff,
> >> +};
> >> +
> >> +static int sprd_pmic_probe(struct spi_device *spi)
> >> +{
> >> +     struct sprd_pmic *sprd_pmic;
> >> +     const struct sprd_pmic_data *data;
> >> +     int ret, i;
> >> +
> >> +     data = of_device_get_match_data(&spi->dev);
> >> +     if (!data) {
> >> +             dev_err(&spi->dev, "No matching driver data found\n");
> >> +             return -EINVAL;
> >> +     }
> >> +
> >> +     sprd_pmic = devm_kzalloc(&spi->dev, sizeof(*sprd_pmic), GFP_KERNEL);
> >> +     if (!sprd_pmic)
> >> +             return -ENOMEM;
> >> +
> >> +     sprd_pmic->regmap = devm_regmap_init(&spi->dev, &sprd_pmic_regmap,
> >> +                                          &spi->dev, &sprd_pmic_config);
> >> +     if (IS_ERR(sprd_pmic->regmap)) {
> >> +             ret = PTR_ERR(sprd_pmic->regmap);
> >> +             dev_err(&spi->dev, "Failed to allocate register map %d\n", ret);
> >> +             return ret;
> >> +     }
> >> +
> >> +     spi_set_drvdata(spi, sprd_pmic);
> >> +     sprd_pmic->dev = &spi->dev;
> >> +     sprd_pmic->irq = spi->irq;
> >> +
> >> +     sprd_pmic->irq_chip.name = dev_name(&spi->dev);
> >> +     sprd_pmic->irq_chip.status_base =
> >> +             data->irq_base + SPRD_PMIC_INT_MASK_STATUS;
> >> +     sprd_pmic->irq_chip.mask_base = data->irq_base + SPRD_PMIC_INT_EN;
> >> +     sprd_pmic->irq_chip.ack_base = 0;
> >> +     sprd_pmic->irq_chip.num_regs = 1;
> >> +     sprd_pmic->irq_chip.num_irqs = data->num_irqs;
> >> +     sprd_pmic->irq_chip.mask_invert = true;
> >> +
> >> +     sprd_pmic->irqs = devm_kzalloc(&spi->dev, sizeof(struct regmap_irq) *
> >> +                                    data->num_irqs, GFP_KERNEL);
> >> +     if (!sprd_pmic->irqs)
> >> +             return -ENOMEM;
> >> +
> >> +     sprd_pmic->irq_chip.irqs = sprd_pmic->irqs;
> >> +     for (i = 0; i < data->num_irqs; i++) {
> >> +             sprd_pmic->irqs[i].reg_offset = i / data->num_irqs;
> >> +             sprd_pmic->irqs[i].mask = BIT(i % data->num_irqs);
> >> +     }
> >
> > Why don't you do this live, instead of pre-calculating?
> 
> Since the SC27xx series PMICs have different interrupts number (such
> as SC2731 has 16 interrupts and SC2720 has 6 interrupts).

Right, so save num_irqs in your device data structure.
Baolin Wang Oct. 13, 2017, 1:28 p.m. | #7
On 13 October 2017 at 17:55, Lee Jones <lee.jones@linaro.org> wrote:
> On Fri, 13 Oct 2017, Baolin Wang wrote:
>> On 13 October 2017 at 17:07, Lee Jones <lee.jones@linaro.org> wrote:
>> > On Wed, 11 Oct 2017, Baolin Wang wrote:
>> >
>> >> This patch adds the binding documentation for Spreadtrum SC27xx series
>> >> PMIC device.
>> >>
>> >> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
>> >> ---
>> >>  .../devicetree/bindings/mfd/sprd,sc27xx-pmic.txt   |   23 ++++++++++++++++++++
>> >>  1 file changed, 23 insertions(+)
>> >>  create mode 100644 Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
>> >>
>> >> diff --git a/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
>> >> new file mode 100644
>> >> index 0000000..333c818
>> >> --- /dev/null
>> >> +++ b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
>> >> @@ -0,0 +1,23 @@
>> >> +Spreadtrum SC27xx Power Management Integrated Circuit (PMIC)
>> >
>> > More info please.
>> >
>> > What does the ship do and what other devices are available.
>>
>> OK. I will add more information in next version.
>>
>> >
>> >> +Required properties:
>> >> +- compatible: Should be "sprd,sc2731".
>> >> +- reg: SPI chip select.
>> >
>> > Really?  Not an address?
>>
>> Yes, it should be device address.
>>
>> >
>> > What is the range?
>> >
>> >> +- spi-max-frequency: Typically set to 26000000.
>> >> +- interrupts: The interrupt line the device is connected to.
>> >> +- interrupt-controller: Marks the device node as an interrupt controller.
>> >> +- #interrupt-cells: The number of cells to describe an PMIC IRQ, should be 2.
>> >
>> > What if it's not 2?  Will it still work?
>>
>> Must be 2, if not it can not work well. Will update in next version.
>>
>> >
>> >> +- #address-cells: Child device offset number of cells, should be 1.
>> >
>> > Same.
>>
>> OK.
>>
>> >
>> >> +- #size-cells: Child device size number of cells, should be 0.
>> >
>> > Same.
>>
>> OK.
>>
>> >
>> >> +
>> >> +Example:
>> >> +pmic: pmic@0 {
>> >
>> > What other nodes are you referencing this one from?
>>
>> This node should be under our ADI/SPI master device node, as one SPI
>> device. I will add the SPI master node in next version. Very
>> appreciated for your comments.
>
> Sorry, what I'm getting at is; is the 'pmic:' label really required?

Ah, sorry for misunderstanding your point. You are right, I will
remove the redundant 'pmic' label in next version. Thanks.
Baolin Wang Oct. 13, 2017, 1:40 p.m. | #8
On 13 October 2017 at 18:13, Lee Jones <lee.jones@linaro.org> wrote:
> On Fri, 13 Oct 2017, Baolin Wang wrote:
>> On 13 October 2017 at 17:26, Lee Jones <lee.jones@linaro.org> wrote:
>> > On Wed, 11 Oct 2017, Baolin Wang wrote:
>> >
>> >> This patch adds support for Spreadtrum SC27xx series PMIC MFD core, and It
>> >> provides communication through the SPI interfaces. The SC27xx series PMICs
>> >> contains the following 6 major components:
>> >> - DCDCs
>> >> - LDOs
>> >> - Battery management system
>> >> - Audio codec
>> >> - User interface function, such as indicator, flash LED
>> >> - IC level function, such as power on/off, type-c
>> >>
>> >> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
>> >> ---
>> >>  drivers/mfd/Kconfig           |   10 ++
>> >>  drivers/mfd/Makefile          |    1 +
>> >>  drivers/mfd/sprd-sc27xx-spi.c |  273 +++++++++++++++++++++++++++++++++++++++++
>> >>  3 files changed, 284 insertions(+)
>> >>  create mode 100644 drivers/mfd/sprd-sc27xx-spi.c
>> >>
>> >> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> >> index fc5e4fe..4753cd5 100644
>> >> --- a/drivers/mfd/Kconfig
>> >> +++ b/drivers/mfd/Kconfig
>> >> @@ -1057,6 +1057,16 @@ config MFD_SMSC
>> >>          To compile this driver as a module, choose M here: the
>> >>          module will be called smsc.
>> >>
>> >> +config MFD_SC27XX_PMIC
>> >> +     tristate "Spreadtrum SC27xx PMICs"
>> >> +     depends on ARCH_SPRD || COMPILE_TEST
>> >> +     depends on SPI_MASTER
>> >> +     select MFD_CORE
>> >> +     select REGMAP_SPI
>> >> +     select REGMAP_IRQ
>> >> +     help
>> >> +       This enables support for the Spreadtrum SC27xx PMICs.
>> >> +
>> >>  config ABX500_CORE
>> >>       bool "ST-Ericsson ABX500 Mixed Signal Circuit register functions"
>> >>       default y if ARCH_U300 || ARCH_U8500 || COMPILE_TEST
>> >> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>> >> index c3d0a1b..a377e0f 100644
>> >> --- a/drivers/mfd/Makefile
>> >> +++ b/drivers/mfd/Makefile
>> >> @@ -226,3 +226,4 @@ obj-$(CONFIG_MFD_SUN4I_GPADC)     += sun4i-gpadc.o
>> >>  obj-$(CONFIG_MFD_STM32_LPTIMER)      += stm32-lptimer.o
>> >>  obj-$(CONFIG_MFD_STM32_TIMERS)       += stm32-timers.o
>> >>  obj-$(CONFIG_MFD_MXS_LRADC)     += mxs-lradc.o
>> >> +obj-$(CONFIG_MFD_SC27XX_PMIC)        += sprd-sc27xx-spi.o
>> >> diff --git a/drivers/mfd/sprd-sc27xx-spi.c b/drivers/mfd/sprd-sc27xx-spi.c
>> >> new file mode 100644
>> >> index 0000000..2b3f2bc
>> >> --- /dev/null
>> >> +++ b/drivers/mfd/sprd-sc27xx-spi.c
>> >> @@ -0,0 +1,273 @@
>> >> +/*
>> >> + * Copyright (C) 2017 Spreadtrum Communications Inc.
>> >> + *
>> >> + * This software is licensed under the terms of the GNU General Public
>> >> + * License version 2, as published by the Free Software Foundation, and
>> >> + * may be copied, distributed, and modified under those terms.
>> >> + *
>> >> + * 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.
>> >> + */
>
> [...]
>
>> >> +static int sprd_pmic_spi_read(void *context,
>> >> +                           const void *reg, size_t reg_size,
>> >> +                           void *val, size_t val_size)
>> >> +{
>> >> +     struct device *dev = context;
>> >> +     struct spi_device *spi = to_spi_device(dev);
>> >> +     u32 rx_buf[2] = { 0 };
>> >> +     int ret;
>> >> +
>> >> +     rx_buf[0] = *(u32 *)reg;
>> >> +     ret = spi_read(spi, rx_buf, 1);
>> >> +     if (ret < 0)
>> >> +             return ret;
>> >> +
>> >> +     memcpy(val, rx_buf, val_size);
>> >
>> > This looks like you're asking for trouble.
>> >
>> > What if val_size > sizeof(rx_buf)?
>> >
>> > You should probably check for that.
>>
>> Since we always read one register every time, which means the reg_size
>> and val_size are always 4. But it will be more helpful to check
>> incorrect parameters by adding one check here.
>>
>> >
>> >> +     return 0;
>> >> +}
>> >> +
>> >> +static struct regmap_bus sprd_pmic_regmap = {
>> >> +     .write = sprd_pmic_spi_write,
>> >> +     .read = sprd_pmic_spi_read,
>> >> +     .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
>> >> +     .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
>> >> +};
>> >> +
>> >> +static const struct regmap_config sprd_pmic_config = {
>> >> +     .reg_bits = 32,
>> >> +     .val_bits = 32,
>> >> +     .reg_stride = 4,
>> >> +     .max_register = 0xffff,
>> >> +};
>> >> +
>> >> +static int sprd_pmic_probe(struct spi_device *spi)
>> >> +{
>> >> +     struct sprd_pmic *sprd_pmic;
>> >> +     const struct sprd_pmic_data *data;
>> >> +     int ret, i;
>> >> +
>> >> +     data = of_device_get_match_data(&spi->dev);
>> >> +     if (!data) {
>> >> +             dev_err(&spi->dev, "No matching driver data found\n");
>> >> +             return -EINVAL;
>> >> +     }
>> >> +
>> >> +     sprd_pmic = devm_kzalloc(&spi->dev, sizeof(*sprd_pmic), GFP_KERNEL);
>> >> +     if (!sprd_pmic)
>> >> +             return -ENOMEM;
>> >> +
>> >> +     sprd_pmic->regmap = devm_regmap_init(&spi->dev, &sprd_pmic_regmap,
>> >> +                                          &spi->dev, &sprd_pmic_config);
>> >> +     if (IS_ERR(sprd_pmic->regmap)) {
>> >> +             ret = PTR_ERR(sprd_pmic->regmap);
>> >> +             dev_err(&spi->dev, "Failed to allocate register map %d\n", ret);
>> >> +             return ret;
>> >> +     }
>> >> +
>> >> +     spi_set_drvdata(spi, sprd_pmic);
>> >> +     sprd_pmic->dev = &spi->dev;
>> >> +     sprd_pmic->irq = spi->irq;
>> >> +
>> >> +     sprd_pmic->irq_chip.name = dev_name(&spi->dev);
>> >> +     sprd_pmic->irq_chip.status_base =
>> >> +             data->irq_base + SPRD_PMIC_INT_MASK_STATUS;
>> >> +     sprd_pmic->irq_chip.mask_base = data->irq_base + SPRD_PMIC_INT_EN;
>> >> +     sprd_pmic->irq_chip.ack_base = 0;
>> >> +     sprd_pmic->irq_chip.num_regs = 1;
>> >> +     sprd_pmic->irq_chip.num_irqs = data->num_irqs;
>> >> +     sprd_pmic->irq_chip.mask_invert = true;
>> >> +
>> >> +     sprd_pmic->irqs = devm_kzalloc(&spi->dev, sizeof(struct regmap_irq) *
>> >> +                                    data->num_irqs, GFP_KERNEL);
>> >> +     if (!sprd_pmic->irqs)
>> >> +             return -ENOMEM;
>> >> +
>> >> +     sprd_pmic->irq_chip.irqs = sprd_pmic->irqs;
>> >> +     for (i = 0; i < data->num_irqs; i++) {
>> >> +             sprd_pmic->irqs[i].reg_offset = i / data->num_irqs;
>> >> +             sprd_pmic->irqs[i].mask = BIT(i % data->num_irqs);
>> >> +     }
>> >
>> > Why don't you do this live, instead of pre-calculating?
>>
>> Since the SC27xx series PMICs have different interrupts number (such
>> as SC2731 has 16 interrupts and SC2720 has 6 interrupts).
>
> Right, so save num_irqs in your device data structure.

Yes. I will add some doc to describe why we need 'sprd_pmic_data'
structure as match data for different PMICs in this SC27xx series.

Patch

diff --git a/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
new file mode 100644
index 0000000..333c818
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/sprd,sc27xx-pmic.txt
@@ -0,0 +1,23 @@ 
+Spreadtrum SC27xx Power Management Integrated Circuit (PMIC)
+
+Required properties:
+- compatible: Should be "sprd,sc2731".
+- reg: SPI chip select.
+- spi-max-frequency: Typically set to 26000000.
+- interrupts: The interrupt line the device is connected to.
+- interrupt-controller: Marks the device node as an interrupt controller.
+- #interrupt-cells: The number of cells to describe an PMIC IRQ, should be 2.
+- #address-cells: Child device offset number of cells, should be 1.
+- #size-cells: Child device size number of cells, should be 0.
+
+Example:
+pmic: pmic@0 {
+	compatible = "sprd,sc2731";
+	reg = <0>;
+	spi-max-frequency = <26000000>;
+	interrupts = <GIC_SPI 31 IRQ_TYPE_LEVEL_HIGH>;
+	interrupt-controller;
+	#interrupt-cells = <2>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+};