Re: [PATCH v3 1/7] mfd: qcom-spmi-pmic: expose the PMIC revid information to clients

[Caleb Connolly <caleb.connolly@xxxxxxxxxx>]

On 09/01/2022 16:57, Jonathan Cameron wrote:
> On Thu,  6 Jan 2022 17:31:25 +0000
> Caleb Connolly <caleb.connolly@xxxxxxxxxx> wrote:
>
> > Some PMIC functions such as the RRADC need to be aware of the PMIC
> > chip revision information to implement errata or otherwise adjust
> > behaviour, export the PMIC information to enable this.
> >
> > This is specifically required to enable the RRADC to adjust
> > coefficients based on which chip fab the PMIC was produced in,
> > this can vary per unique device and therefore has to be read at
> > runtime.
> >
> > Signed-off-by: Caleb Connolly <caleb.connolly@xxxxxxxxxx>
> Hi Caleb,
>
> Some comments inline.
Hi Jonathan,

Thanks for the feedback, I had a question about one of your points below.
> Thanks,
>
> Jonathan
>
> > ---
> >   drivers/mfd/qcom-spmi-pmic.c | 108 +++++++++++++++++------------------
> >   include/soc/qcom/qcom-pmic.h |  63 ++++++++++++++++++++
> >   2 files changed, 114 insertions(+), 57 deletions(-)
> >   create mode 100644 include/soc/qcom/qcom-pmic.h
> >
> > diff --git a/drivers/mfd/qcom-spmi-pmic.c b/drivers/mfd/qcom-spmi-pmic.c
> > index 1cacc00aa6c9..6b75c2f52b74 100644
> > --- a/drivers/mfd/qcom-spmi-pmic.c
> > +++ b/drivers/mfd/qcom-spmi-pmic.c
> > @@ -3,51 +3,24 @@
> >    * Copyright (c) 2014, The Linux Foundation. All rights reserved.
> >    */
> >   
> > +#include <linux/device.h>
> > +#include <linux/gfp.h>
> >   #include <linux/kernel.h>
> >   #include <linux/module.h>
> > +#include <linux/slab.h>
> >   #include <linux/spmi.h>
> >   #include <linux/regmap.h>
> >   #include <linux/of_platform.h>
> > +#include <soc/qcom/qcom-pmic.h>
> >   
> >   #define PMIC_REV2		0x101
> >   #define PMIC_REV3		0x102
> >   #define PMIC_REV4		0x103
> >   #define PMIC_TYPE		0x104
> >   #define PMIC_SUBTYPE		0x105
> > -
> > +#define PMIC_FAB_ID		0x1f2
> >   #define PMIC_TYPE_VALUE		0x51
> >   
> > -#define COMMON_SUBTYPE		0x00
> > -#define PM8941_SUBTYPE		0x01
> > -#define PM8841_SUBTYPE		0x02
> > -#define PM8019_SUBTYPE		0x03
> > -#define PM8226_SUBTYPE		0x04
> > -#define PM8110_SUBTYPE		0x05
> > -#define PMA8084_SUBTYPE		0x06
> > -#define PMI8962_SUBTYPE		0x07
> > -#define PMD9635_SUBTYPE		0x08
> > -#define PM8994_SUBTYPE		0x09
> > -#define PMI8994_SUBTYPE		0x0a
> > -#define PM8916_SUBTYPE		0x0b
> > -#define PM8004_SUBTYPE		0x0c
> > -#define PM8909_SUBTYPE		0x0d
> > -#define PM8028_SUBTYPE		0x0e
> > -#define PM8901_SUBTYPE		0x0f
> > -#define PM8950_SUBTYPE		0x10
> > -#define PMI8950_SUBTYPE		0x11
> > -#define PM8998_SUBTYPE		0x14
> > -#define PMI8998_SUBTYPE		0x15
> > -#define PM8005_SUBTYPE		0x18
> > -#define PM660L_SUBTYPE		0x1A
> > -#define PM660_SUBTYPE		0x1B
> > -#define PM8150_SUBTYPE		0x1E
> > -#define PM8150L_SUBTYPE		0x1f
> > -#define PM8150B_SUBTYPE		0x20
> > -#define PMK8002_SUBTYPE		0x21
> > -#define PM8009_SUBTYPE		0x24
> > -#define PM8150C_SUBTYPE		0x26
> > -#define SMB2351_SUBTYPE		0x29
> > -
> >   static const struct of_device_id pmic_spmi_id_table[] = {
> >   	{ .compatible = "qcom,pm660",     .data = (void *)PM660_SUBTYPE },
> >   	{ .compatible = "qcom,pm660l",    .data = (void *)PM660L_SUBTYPE },
> > @@ -81,42 +54,47 @@ static const struct of_device_id pmic_spmi_id_table[] = {
> >   	{ }
> >   };
> >   
> > -static void pmic_spmi_show_revid(struct regmap *map, struct device *dev)
> > +static int pmic_spmi_load_revid(struct regmap *map, struct device *dev,
> > +				 struct qcom_spmi_pmic *pmic)
> >   {
> > -	unsigned int rev2, minor, major, type, subtype;
> > -	const char *name = "unknown";
> >   	int ret, i;
> >   
> > -	ret = regmap_read(map, PMIC_TYPE, &type);
> > +	ret = regmap_read(map, PMIC_TYPE, &pmic->type);
> >   	if (ret < 0)
> > -		return;
> > +		return ret;
> >   
> > -	if (type != PMIC_TYPE_VALUE)
> > -		return;
> > +	if (pmic->type != PMIC_TYPE_VALUE)
> > +		return ret;
> >   
> > -	ret = regmap_read(map, PMIC_SUBTYPE, &subtype);
> > +	ret = regmap_read(map, PMIC_SUBTYPE, &pmic->subtype);
> >   	if (ret < 0)
> > -		return;
> > +		return ret;
> >   
> >   	for (i = 0; i < ARRAY_SIZE(pmic_spmi_id_table); i++) {
> > -		if (subtype == (unsigned long)pmic_spmi_id_table[i].data)
> > +		if (pmic->subtype == (unsigned long)pmic_spmi_id_table[i].data)
> >   			break;
> >   	}
> >   
> >   	if (i != ARRAY_SIZE(pmic_spmi_id_table))
> > -		name = pmic_spmi_id_table[i].compatible;
> > +		pmic->name = devm_kstrdup_const(dev, pmic_spmi_id_table[i].compatible, GFP_KERNEL);
>
> Managed allocation that you call kfree on in remove().
>
> >   
> > -	ret = regmap_read(map, PMIC_REV2, &rev2);
> > +	ret = regmap_read(map, PMIC_REV2, &pmic->rev2);
> >   	if (ret < 0)
> > -		return;
> > +		return ret;
> >   
> > -	ret = regmap_read(map, PMIC_REV3, &minor);
> > +	ret = regmap_read(map, PMIC_REV3, &pmic->minor);
> >   	if (ret < 0)
> > -		return;
> > +		return ret;
> >   
> > -	ret = regmap_read(map, PMIC_REV4, &major);
> > +	ret = regmap_read(map, PMIC_REV4, &pmic->major);
> >   	if (ret < 0)
> > -		return;
> > +		return ret;
> > +
> > +	if (pmic->subtype == PMI8998_SUBTYPE || pmic->subtype == PM660_SUBTYPE) {
> > +		ret = regmap_read(map, PMIC_FAB_ID, &pmic->fab_id);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> >   
> >   	/*
> >   	 * In early versions of PM8941 and PM8226, the major revision number
> > @@ -124,14 +102,14 @@ static void pmic_spmi_show_revid(struct regmap *map, struct device *dev)
> >   	 * Increment the major revision number here if the chip is an early
> >   	 * version of PM8941 or PM8226.
> >   	 */
> > -	if ((subtype == PM8941_SUBTYPE || subtype == PM8226_SUBTYPE) &&
> > -	    major < 0x02)
> > -		major++;
> > +	if ((pmic->subtype == PM8941_SUBTYPE || pmic->subtype == PM8226_SUBTYPE) &&
> > +	    pmic->major < 0x02)
> > +		pmic->major++;
> >   
> > -	if (subtype == PM8110_SUBTYPE)
> > -		minor = rev2;
> > +	if (pmic->subtype == PM8110_SUBTYPE)
> > +		pmic->minor = pmic->rev2;
> >   
> > -	dev_dbg(dev, "%x: %s v%d.%d\n", subtype, name, major, minor);
> > +	return 0;
> >   }
> >   
> >   static const struct regmap_config spmi_regmap_config = {
> > @@ -144,22 +122,38 @@ static const struct regmap_config spmi_regmap_config = {
> >   static int pmic_spmi_probe(struct spmi_device *sdev)
> >   {
> >   	struct regmap *regmap;
> > +	struct qcom_spmi_pmic *pmic;
> >   
> >   	regmap = devm_regmap_init_spmi_ext(sdev, &spmi_regmap_config);
> >   	if (IS_ERR(regmap))
> >   		return PTR_ERR(regmap);
> >   
> > +	pmic = devm_kzalloc(&sdev->dev, sizeof(*pmic), GFP_KERNEL);
> > +	if (!pmic)
> > +		return -ENOMEM;
>
> Within the code visible here, why can't this just be on the stack?
I allocated on the heap beacuse the data has to be read by other drivers 
(it's handed over in spmi_device_set_drvdata() below). I don't have a 
whole lot of C experience so please forgive the potentially ignorant 
questions - is it ok to allocate on the stack if the object needs to 
have a lifetime longer than the function?
> > +
> >   	/* Only the first slave id for a PMIC contains this information */
> > -	if (sdev->usid % 2 == 0)
> > -		pmic_spmi_show_revid(regmap, &sdev->dev);
> > +	if (sdev->usid % 2 == 0) {
> > +		pmic_spmi_load_revid(regmap, &sdev->dev, pmic);
> > +		spmi_device_set_drvdata(sdev, pmic);
> > +		qcom_pmic_print_info(&sdev->dev, pmic);
> > +	}
> >   
> >   	return devm_of_platform_populate(&sdev->dev);
> >   }
> >   
> > +static void pmic_spmi_remove(struct spmi_device *sdev)
> > +{
> > +	struct qcom_spmi_pmic *pmic = spmi_device_get_drvdata(sdev);
> > +
> > +	kfree(pmic->name);
>
> Looks like this is cleaning up a managed allocation unless I'm missing something
> which means you'll get a double free on remove.
>
> > +}
> > +
> >   MODULE_DEVICE_TABLE(of, pmic_spmi_id_table);
> >   
> >   static struct spmi_driver pmic_spmi_driver = {
> >   	.probe = pmic_spmi_probe,
> > +	.remove = pmic_spmi_remove,
> >   	.driver = {
> >   		.name = "pmic-spmi",
> >   		.of_match_table = pmic_spmi_id_table,
> > diff --git a/include/soc/qcom/qcom-pmic.h b/include/soc/qcom/qcom-pmic.h
> > new file mode 100644
> > index 000000000000..59114988582d
> > --- /dev/null
> > +++ b/include/soc/qcom/qcom-pmic.h
> > @@ -0,0 +1,63 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/* Copyright (c) 2021 Linaro. All rights reserved.
> > + * Copyright (c) 2021 Caleb Connolly <caleb.connolly@xxxxxxxxxx>
> > + */
> > +
> > +#ifndef __QCOM_PMIC_H__
> > +#define __QCOM_PMIC_H__
> > +
> > +#define COMMON_SUBTYPE		0x00
> > +#define PM8941_SUBTYPE		0x01
> > +#define PM8841_SUBTYPE		0x02
> > +#define PM8019_SUBTYPE		0x03
> > +#define PM8226_SUBTYPE		0x04
> > +#define PM8110_SUBTYPE		0x05
> > +#define PMA8084_SUBTYPE		0x06
> > +#define PMI8962_SUBTYPE		0x07
> > +#define PMD9635_SUBTYPE		0x08
> > +#define PM8994_SUBTYPE		0x09
> > +#define PMI8994_SUBTYPE		0x0a
> > +#define PM8916_SUBTYPE		0x0b
> > +#define PM8004_SUBTYPE		0x0c
> > +#define PM8909_SUBTYPE		0x0d
> > +#define PM8028_SUBTYPE		0x0e
> > +#define PM8901_SUBTYPE		0x0f
> > +#define PM8950_SUBTYPE		0x10
> > +#define PMI8950_SUBTYPE		0x11
> > +#define PM8998_SUBTYPE		0x14
> > +#define PMI8998_SUBTYPE		0x15
> > +#define PM8005_SUBTYPE		0x18
> > +#define PM660L_SUBTYPE		0x1A
> > +#define PM660_SUBTYPE		0x1B
> > +#define PM8150_SUBTYPE		0x1E
> > +#define PM8150L_SUBTYPE		0x1f
> > +#define PM8150B_SUBTYPE		0x20
> > +#define PMK8002_SUBTYPE		0x21
> > +#define PM8009_SUBTYPE		0x24
> > +#define PM8150C_SUBTYPE		0x26
> > +#define SMB2351_SUBTYPE		0x29
> > +
> > +#define PMI8998_FAB_ID_SMIC	0x11
> > +#define PMI8998_FAB_ID_GF	0x30
> > +
> > +#define PM660_FAB_ID_GF		0x0
> > +#define PM660_FAB_ID_TSMC	0x2
> > +#define PM660_FAB_ID_MX		0x3
> > +
> > +struct qcom_spmi_pmic {
> > +	unsigned int type;
> > +	unsigned int subtype;
> > +	unsigned int major;
> > +	unsigned int minor;
> > +	unsigned int rev2;
> > +	unsigned int fab_id;
> > +	const char *name;
> > +};
> > +
> struct device;
>
> > +static inline void qcom_pmic_print_info(struct device *dev, struct qcom_spmi_pmic *pmic)
> > +{
>
> Need an include to get you access to dev_info() and possibly so
>
> Headers should stand and build on their own including any inline functions they
> contain.
>
>
> > +	dev_info(dev, "%x: %s v%d.%d\n",
> > +		pmic->subtype, pmic->name, pmic->major, pmic->minor);
> > +}
> > +
> > +#endif /* __QCOM_PMIC_H__ */

--
Kind Regards,
Caleb (they/them)