Re: [PATCH v6 4/6] mfd: Add hi6421 PMIC core driver
From: Guodong Xu
Date: Mon Aug 25 2014 - 05:17:30 EST
Hi, Lee
Thanks. I added for most of your comments. Some items, I have a
different understanding. I added in below.
On 08/20/2014 04:09 PM, Lee Jones wrote:
> On Mon, 18 Aug 2014, Guodong Xu wrote:
>> This adds driver to support HiSilicon Hi6421 PMIC. Hi6421 includes multi-
>> functions, such as regulators, codec, ADCs, Coulomb counter, etc.
>> This driver includes core APIs _only_.
>>
>> Drivers for individul components, like voltage regulators, are
>> implemented in corresponding driver directories and files.
>>
>> Registers in Hi6421 are memory mapped, so using regmap-mmio API.
>>
>> Signed-off-by: Guodong Xu <guodong.xu@xxxxxxxxxx>
>> ---
>> Documentation/devicetree/bindings/mfd/hi6421.txt | 37 +++++++
>
> DT documentation should be in a patch of its own.
>
> See: Documentation/devicetree/bindings/submitting-patches.txt
>
Thanks. Will do.
>> drivers/mfd/Kconfig | 13 +++
>> drivers/mfd/Makefile | 1 +
>> drivers/mfd/hi6421-pmic-core.c | 117 +++++++++++++++++++++++
>> include/linux/mfd/hi6421-pmic.h | 39 ++++++++
>> 5 files changed, 207 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/mfd/hi6421.txt
>> create mode 100644 drivers/mfd/hi6421-pmic-core.c
>> create mode 100644 include/linux/mfd/hi6421-pmic.h
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/hi6421.txt b/Documentation/devicetree/bindings/mfd/hi6421.txt
>> new file mode 100644
>> index 0000000..1512123
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mfd/hi6421.txt
>> @@ -0,0 +1,37 @@
>> +* HI6421 Multi-Functional Device (MFD), by HiSilicon Ltd.
>> +
>> +Required parent device properties:
>> +- reg : register range space of hi6421;
>
> You need to describe the compatible string here.
>
Yes.
>> +Supported Hi6421 sub-devices include:
>> +
>> +Device IRQ Names Supply Names Description
>> +------ --------- ------------ -----------
>> +regulators : : : Regulators
>
> If a cell has been intentionally left blank, put 'None' to be clear.
>
> When will the other devices be added?
>
RTC and irq will follow up next Month.
>> +Required child device properties:
>> +None.
>> +
>> +Example:
>> + pmic: pmic@c00000 {
>
> 24bit addressing?
>
No. that's due to a range property in parent node. I will change it to
32-bit address.
> Is this node referenced by another node via phandle? If not, you can
> drop the "pmic" label. If it is referenced by another node, but there
> is more than one PMIC, label "pmic" won't do.
>
ok. Will change node name to
+ hi6421 {
...
>> + compatible = "hisilicon,hi6421-pmic";
>> + reg = <0xc00000 0x0180>; /* 0x60 << 2 */
>> +
>> + regulators {
>> + // supply for MLC NAND/ eMMC
>> + hi6421_vout0_reg: hi6421_vout0 {
>> + regulator-name = "VOUT0";
>
> I may be mistaken, but "vout0" doesn't come across as a very good
> regulator name to me.
>
Right, but 'VOUT0' is the name used in hi4511 boards' schematic. So I
used this name to facilitate dts and board design matching.
>> + regulator-min-microvolt = <2850000>;
>> + regulator-max-microvolt = <2850000>;
>> + };
>> +
>> + // supply for 26M Oscillator
>> + hi6421_vout1_reg: hi6421_vout1 {
>> + regulator-name = "VOUT1";
>> + regulator-min-microvolt = <1700000>;
>> + regulator-max-microvolt = <2000000>;
>> + regulator-boot-on;
>> + regulator-always-on;
>
> Again an assumption here, but doesn't 'egulator-always-on' insinuate
> 'regulator-boot-on', or does it simply mean "once it's on, it must
> stay on"?
>
>From Documentation/devicetree/bindings/regulator/regulator.txt,
- regulator-boot-on: bootloader/firmware enabled regulator
- regulator-always-on: boolean, regulator should never be disabled
'regulator-boot-on' is describing a board status, so I added it into dts
file. Although in kernel code there is no much operation depending on it.
>> + };
>> + };
>> + };
>
> Your tabbing is out here.
>
Sorry. will fix.
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index de5abf2..347cbf6 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -210,6 +210,19 @@ config MFD_MC13XXX_I2C
>> help
>> Select this if your MC13xxx is connected via an I2C bus.
>>
>> +config MFD_HI6421_PMIC
>> + tristate "HiSilicon Hi6421 PMU/Codec IC"
>> + depends on OF
>> + select MFD_CORE
>> + select REGMAP_MMIO
>> + help
>> + This driver supports HiSilicon Hi6421 PMIC. Hi6421 includes multi-
>
> It doesn't support it, it adds support for it - subtle difference.
>
Thanks, will fix.
>> + functions, such as regulators, codec, ADCs, Coulomb counter, etc.
>> + This driver includes core APIs _only_. You have to select
>> + individul components like voltage regulators under corresponding
>> + menus in order to enable them.
>> + Memory-mapped I/O is the way to communicate with Hi6421.
>
> "We communicate with the Hi6421 via memory-mapped I/O."
>
>> config HTC_EGPIO
>> bool "HTC EGPIO support"
>> depends on GPIOLIB && ARM
>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>> index f001487..dc59efd 100644
>> --- a/drivers/mfd/Makefile
>> +++ b/drivers/mfd/Makefile
>> @@ -169,6 +169,7 @@ obj-$(CONFIG_MFD_AS3711) += as3711.o
>> obj-$(CONFIG_MFD_AS3722) += as3722.o
>> obj-$(CONFIG_MFD_STW481X) += stw481x.o
>> obj-$(CONFIG_MFD_IPAQ_MICRO) += ipaq-micro.o
>> +obj-$(CONFIG_MFD_HI6421_PMIC) += hi6421-pmic-core.o
>>
>> intel-soc-pmic-objs := intel_soc_pmic_core.o intel_soc_pmic_crc.o
>> obj-$(CONFIG_INTEL_SOC_PMIC) += intel-soc-pmic.o
>> diff --git a/drivers/mfd/hi6421-pmic-core.c b/drivers/mfd/hi6421-pmic-core.c
>> new file mode 100644
>> index 0000000..2be4d3f
>> --- /dev/null
>> +++ b/drivers/mfd/hi6421-pmic-core.c
>> @@ -0,0 +1,117 @@
>> +/*
>> + * Device driver for Hi6421 IC
>> + *
>> + * Copyright (c) <2011-2014> HiSilicon Technologies Co., Ltd.
>> + * http://www.hisilicon.com
>> + * Copyright (c) <2013-2014> Linaro Ltd.
>> + * http://www.linaro.org
>
> I'm not sure Linaro own the copyright to this driver. It should still
> belong to HiSilicon.
>
That was discussed with HiSilicon and agreement was we need both. The
driver code is a complete re-write by me. HiSilicon original driver is
reference for functionality understanding purpose.
>> + * Author: Guodong Xu <guodong.xu@xxxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>
> This should also contain a link to the full licence.
>
> See: COPYING
>
Thanks. I checked COPYING, but there is no 'link' to full license. I
copied a link from other c source: http://www.gnu.org/licenses/
is that OK?
>> + */
>> +
>> +#include <linux/device.h>
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/mfd/core.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/of_address.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +#include <linux/slab.h>
>> +#include <linux/mfd/hi6421-pmic.h>
>> +
>> +static struct of_device_id of_hi6421_pmic_match_tbl[] = {
>> + {
>> + .compatible = "hisilicon,hi6421-pmic",
>> + },
>
> This can be just one line.
>
>> + { /* end */ }
>
> No real need for this comment.
>
Fixed.
>> +};
>> +
>> +static const struct mfd_cell hi6421_devs[] = {
>> + {
>> + .name = "hi6421-regulator",
>> + },
>
> Again, one line.
>
>> +};
>> +
>> +static struct regmap_config hi6421_regmap_config = {
>> + .reg_bits = 32,
>> + .reg_stride = 4,
>> + .val_bits = 8,
>> + .max_register = HI6421_REG_TO_BUS_ADDR(0xFF),
>
> 0xFF should really be defined.
>
>> +};
>> +
>> +static int hi6421_pmic_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>
> You only use this a couple of times. You use '&pdev->dev' more
> regularly. May as well remove it and just use '&pdev->dev' all
> the time.
>
Right. Will fix.
>> + struct hi6421_pmic *pmic = NULL;
>
> No need to initialise this.
>
>> + struct resource *res;
>> + void __iomem *base;
>> + int ret;
>> +
>> + pmic = devm_kzalloc(dev, sizeof(*pmic), GFP_KERNEL);
>> + if (!pmic) {
>> + dev_err(dev, "cannot allocate hi6421_pmic device info\n");
>
> No need to print out messages on OOM, the OS will do that for you.
>
>> + return -ENOMEM;
>> + }
>> +
>> + /* get resources */
>
> This comment doesn't add to the code. The name of the function call
> is clear enough.
>
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (unlikely(!res)) {
>
> Only 21 out of 1718 uses of platform_get_resource() use unlikely() to
> check the return value. I think it's okay to drop it.
>
>> + dev_err(&pdev->dev, "Invalid mem resource.\n");
>
> "No memory resource specified"?
>
>> + return -ENODEV;
>> + }
>
> Actually, scrap all that. You can remove error checking altogether
> for platform_get_resource(), as devm_ioremap_resource() does it for
> you. Code should read:
>
Thanks. Will do.
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> base = devm_ioremap_resource(dev, res);
> if (IS_ERR(base))
> return PTR_ERR(base);
>
>> + base = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(base))
>> + return PTR_ERR(base);
>> +
>> + pmic->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
>> + &hi6421_regmap_config);
>> + if (IS_ERR(pmic->regmap)) {
>> + dev_err(&pdev->dev, "regmap init failed: %ld\n",
>> + PTR_ERR(pmic->regmap));
>
> Can you break the line at the first ',/' and line up against '('?
>
>> + return PTR_ERR(pmic->regmap);
>> + }
>> +
>> + pmic->dev = dev;
>> + platform_set_drvdata(pdev, pmic);
>
> It's not _that_ important, but I like to see this at the end after you
> know everything else has succeeded.
>
When I move this after mfd_add_devices(), it fails to boot. In mfd
devices's probe, pmic->regmap is used.
>> + /* set over-current protection debounce 8ms*/
>
> Should be a ' ' between '8ms' and '*/'.
>
>> + regmap_update_bits(pmic->regmap, HI6421_OCP_DEB_CTRL_REG,
>> + (HI6421_OCP_DEB_SEL_MASK | HI6421_OCP_EN_DEBOUNCE_MASK |
>> + HI6421_OCP_AUTO_STOP_MASK),
>> + (HI6421_OCP_DEB_SEL_8MS | HI6421_OCP_EN_DEBOUNCE_ENABLE));
>> +
>> + ret = mfd_add_devices(dev, 0, hi6421_devs,
>> + ARRAY_SIZE(hi6421_devs), NULL, 0, NULL);
>
> I'd like to see an error message if mfd_add_devices() fails.
>
Will do.
>> + return ret;
>> +}
>> +
>> +static int hi6421_pmic_remove(struct platform_device *pdev)
>> +{
>> + mfd_remove_devices(&pdev->dev);
>> +
>> + return 0;
>> +}
>> +
>> +static struct platform_driver hi6421_pmic_driver = {
>> + .driver = {
>> + .name = "hi6421_pmic",
>> + .owner = THIS_MODULE,
>
> This is taken care of for you, you can remove it.
>
Will do.
>> + .of_match_table = of_hi6421_pmic_match_tbl,
>> + },
>> + .probe = hi6421_pmic_probe,
>> + .remove = hi6421_pmic_remove,
>> +};
>> +module_platform_driver(hi6421_pmic_driver);
>> +
>> +MODULE_AUTHOR("Guodong Xu <guodong.xu@xxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Hi6421 PMIC driver");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/include/linux/mfd/hi6421-pmic.h b/include/linux/mfd/hi6421-pmic.h
>> new file mode 100644
>> index 0000000..36bcb34
>> --- /dev/null
>> +++ b/include/linux/mfd/hi6421-pmic.h
>> @@ -0,0 +1,39 @@
>> +/*
>> + * Header file for device driver Hi6421 PMIC
>> + *
>> + * Copyright (c) <2011-2014> HiSilicon Technologies Co., Ltd.
>> + * http://www.hisilicon.com
>> + * Copyright (c) <2013-2014> Linaro Ltd.
>> + * http://www.linaro.org
>> + *
>> + * Author: Guodong Xu <guodong.xu@xxxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#ifndef __HI6421_PMIC_H
>> +#define __HI6421_PMIC_H
>> +
>> +/* Hi6421 registers are mapped to memory bus in 4 bytes stride */
>> +#define HI6421_REG_TO_BUS_ADDR(x) (x << 2)
>> +
>> +/* Hi6421 OCP (over current protection) and DEB (debounce) control register */
>> +#define HI6421_OCP_DEB_CTRL_REG HI6421_REG_TO_BUS_ADDR(0x51)
>> +#define HI6421_OCP_DEB_SEL_MASK (0x0C)
>> +#define HI6421_OCP_DEB_SEL_8MS (0x00)
>> +#define HI6421_OCP_DEB_SEL_16MS (0x04)
>> +#define HI6421_OCP_DEB_SEL_32MS (0x08)
>> +#define HI6421_OCP_DEB_SEL_64MS (0x0C)
>> +#define HI6421_OCP_EN_DEBOUNCE_MASK (0x02)
>> +#define HI6421_OCP_EN_DEBOUNCE_ENABLE (0x02)
>> +#define HI6421_OCP_AUTO_STOP_MASK (0x01)
>> +#define HI6421_OCP_AUTO_STOP_ENABLE (0x01)
>
> Remove the ()'s.
>
Will do.
Thanks.
Guodong
>> +struct hi6421_pmic {
>> + struct device *dev;
>> + struct regmap *regmap;
>> +};
>> +
>> +#endif /* __HI6421_PMIC_H */
>
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