Date:   Fri, 5 May 2023 21:01:23 +0100
From:   Cristian Marussi <cristian.marussi@....com>
To:     Oleksii Moisieiev <Oleksii_Moisieiev@...m.com>
Cc:     "sudeep.holla@....com" <sudeep.holla@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Peng Fan <peng.fan@....nxp.com>,
        Michal Simek <michal.simek@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>
Subject: Re: [RFC v2 2/3] pinctrl: Implementation of the generic scmi-pinctrl
 driver

On Wed, Apr 26, 2023 at 01:26:37PM +0000, Oleksii Moisieiev wrote:
> scmi-pinctrl driver implements pinctrl driver interface and using
> SCMI protocol to redirect messages from pinctrl subsystem SDK to
> SCP firmware, which does the changes in HW.
> 
> This setup expects SCP firmware (or similar system, such as ATF)
> to be installed on the platform, which implements pinctrl driver
> for the specific platform.
> 
> SCMI-Pinctrl driver should be configured from the device-tree and uses
> generic device-tree mappings for the configuration.
> 

Hi Oleksii,

just a few remarks down below.

> Signed-off-by: Oleksii Moisieiev <oleksii_moisieiev@...m.com>
> ---
>  MAINTAINERS                    |   1 +
>  drivers/pinctrl/Kconfig        |   9 +
>  drivers/pinctrl/Makefile       |   1 +
>  drivers/pinctrl/pinctrl-scmi.c | 578 +++++++++++++++++++++++++++++++++
>  4 files changed, 589 insertions(+)
>  create mode 100644 drivers/pinctrl/pinctrl-scmi.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0d251ebac437..ba9e3aea6176 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -20322,6 +20322,7 @@ M:	Oleksii Moisieiev <oleksii_moisieiev@...m.com>
>  L:	linux-arm-kernel@...ts.infradead.org
>  S:	Maintained
>  F:	drivers/firmware/arm_scmi/pinctrl.c
> +F:	drivers/pinctrl/pinctrl-scmi.c
>  
>  SYSTEM RESET/SHUTDOWN DRIVERS
>  M:	Sebastian Reichel <sre@...nel.org>
> diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
> index dcb53c4a9584..16bf2c67f095 100644
> --- a/drivers/pinctrl/Kconfig
> +++ b/drivers/pinctrl/Kconfig
> @@ -552,4 +552,13 @@ source "drivers/pinctrl/uniphier/Kconfig"
>  source "drivers/pinctrl/visconti/Kconfig"
>  source "drivers/pinctrl/vt8500/Kconfig"
>  
> +config PINCTRL_SCMI
> +	bool "Pinctrl driver controlled via SCMI interface"

Why not a tristate ? The core SCMI stack can be compiled as module with
all the protocols...at least for testing is useful to have this driver
as M.

> +	depends on ARM_SCMI_PROTOCOL || COMPILE_TEST
> +	help
> +	  This driver provides support for pinctrl which is controlled
> +	  by firmware that implements the SCMI interface.
> +	  It uses SCMI Message Protocol to interact with the
> +	  firmware providing all the pinctrl controls.
> +
>  endif
> diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
> index d5939840bb2a..21366db4f4f4 100644
> --- a/drivers/pinctrl/Makefile
> +++ b/drivers/pinctrl/Makefile
> @@ -51,6 +51,7 @@ obj-$(CONFIG_PINCTRL_TB10X)	+= pinctrl-tb10x.o
>  obj-$(CONFIG_PINCTRL_THUNDERBAY) += pinctrl-thunderbay.o
>  obj-$(CONFIG_PINCTRL_ZYNQMP)	+= pinctrl-zynqmp.o
>  obj-$(CONFIG_PINCTRL_ZYNQ)	+= pinctrl-zynq.o
> +obj-$(CONFIG_PINCTRL_SCMI)	+= pinctrl-scmi.o
>  
>  obj-y				+= actions/
>  obj-$(CONFIG_ARCH_ASPEED)	+= aspeed/
> diff --git a/drivers/pinctrl/pinctrl-scmi.c b/drivers/pinctrl/pinctrl-scmi.c
> new file mode 100644
> index 000000000000..8401db1d030b
> --- /dev/null
> +++ b/drivers/pinctrl/pinctrl-scmi.c
> @@ -0,0 +1,578 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * System Control and Power Interface (SCMI) Protocol based pinctrl driver
> + *
> + * Copyright (C) 2023 EPAM
> + */
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/of.h>
> +#include <linux/module.h>
> +#include <linux/seq_file.h>
> +
> +#include <linux/pinctrl/machine.h>
> +#include <linux/pinctrl/pinconf.h>
> +#include <linux/pinctrl/pinconf-generic.h>
> +#include <linux/pinctrl/pinctrl.h>
> +#include <linux/pinctrl/pinmux.h>
> +#include <linux/scmi_protocol.h>
> +#include <linux/slab.h>
> +
> +#include "pinctrl-utils.h"
> +#include "core.h"
> +#include "pinconf.h"
> +
> +#define DRV_NAME "scmi-pinctrl"
> +
> +static const struct scmi_pinctrl_proto_ops *pinctrl_ops;
> +
> +struct scmi_pinctrl_funcs {
> +	unsigned int num_groups;
> +	const char **groups;
> +};
> +
> +struct scmi_pinctrl {
> +	struct device *dev;
> +	struct scmi_protocol_handle *ph;
> +	struct pinctrl_dev *pctldev;
> +	struct pinctrl_desc pctl_desc;
> +	struct scmi_pinctrl_funcs *functions;
> +	unsigned int nr_functions;
> +	char **groups;
> +	unsigned int nr_groups;
> +	struct pinctrl_pin_desc *pins;
> +	unsigned int nr_pins;
> +};
> +
> +static int pinctrl_scmi_get_groups_count(struct pinctrl_dev *pctldev)
> +{
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph)
> +		return -EINVAL;
> +
> +	return pinctrl_ops->get_count(pmx->ph, GROUP_TYPE);
> +}
> +
> +static const char *pinctrl_scmi_get_group_name(struct pinctrl_dev *pctldev,
> +					       unsigned int selector)
> +{
> +	int ret;
> +	const char *name;
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return NULL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph)
> +		return NULL;
> +
> +	ret = pinctrl_ops->get_name(pmx->ph, selector, GROUP_TYPE, &name);
> +	if (ret) {
> +		dev_err(pmx->dev, "get name failed with err %d", ret);
> +		return NULL;
> +	}
> +
> +	return name;
> +}
> +
> +static int pinctrl_scmi_get_group_pins(struct pinctrl_dev *pctldev,
> +				       unsigned int selector,
> +				       const unsigned int **pins,
> +				       unsigned int *num_pins)
> +{
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph)
> +		return -EINVAL;
> +
> +	return pinctrl_ops->get_group_pins(pmx->ph, selector,
> +					   pins, num_pins);
> +}
> +
> +static void pinctrl_scmi_pin_dbg_show(struct pinctrl_dev *pctldev,
> +				      struct seq_file *s,
> +				      unsigned int offset)
> +{
> +	seq_puts(s, DRV_NAME);
> +}
> +
> +#ifdef CONFIG_OF
> +static int pinctrl_scmi_dt_node_to_map(struct pinctrl_dev *pctldev,
> +				       struct device_node *np_config,
> +				       struct pinctrl_map **map,
> +				       u32 *num_maps)
> +{
> +	return pinconf_generic_dt_node_to_map(pctldev, np_config, map,
> +					      num_maps, PIN_MAP_TYPE_INVALID);
> +}
> +
> +static void pinctrl_scmi_dt_free_map(struct pinctrl_dev *pctldev,
> +				     struct pinctrl_map *map, u32 num_maps)
> +{
> +	kfree(map);
> +}
> +
> +#endif /* CONFIG_OF */
> +
> +static const struct pinctrl_ops pinctrl_scmi_pinctrl_ops = {
> +	.get_groups_count = pinctrl_scmi_get_groups_count,
> +	.get_group_name = pinctrl_scmi_get_group_name,
> +	.get_group_pins = pinctrl_scmi_get_group_pins,
> +	.pin_dbg_show = pinctrl_scmi_pin_dbg_show,
> +#ifdef CONFIG_OF
> +	.dt_node_to_map = pinctrl_scmi_dt_node_to_map,
> +	.dt_free_map = pinctrl_scmi_dt_free_map,
> +#endif
> +};
> +
> +static int pinctrl_scmi_get_functions_count(struct pinctrl_dev *pctldev)
> +{
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph)
> +		return -EINVAL;
> +
> +	return pinctrl_ops->get_count(pmx->ph, FUNCTION_TYPE);
> +}
> +
> +static const char *pinctrl_scmi_get_function_name(struct pinctrl_dev *pctldev,
> +						  unsigned int selector)
> +{
> +	int ret;
> +	const char *name;
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return NULL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph)
> +		return NULL;
> +
> +	ret = pinctrl_ops->get_name(pmx->ph, selector, FUNCTION_TYPE, &name);
> +	if (ret) {
> +		dev_err(pmx->dev, "get name failed with err %d", ret);
> +		return NULL;
> +	}
> +
> +	return name;
> +}
> +
> +static int pinctrl_scmi_get_function_groups(struct pinctrl_dev *pctldev,
> +					    unsigned int selector,
> +					    const char * const **groups,
> +					    unsigned int * const num_groups)
> +{
> +	const unsigned int *group_ids;
> +	int ret, i;
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph || !groups || !num_groups)
> +		return -EINVAL;
> +
> +	if (selector < pmx->nr_functions &&
> +	    pmx->functions[selector].num_groups) {
> +		*groups = (const char * const *)pmx->functions[selector].groups;
> +		*num_groups = pmx->functions[selector].num_groups;
> +		return 0;
> +	}
> +
> +	ret = pinctrl_ops->get_function_groups(pmx->ph, selector,
> +					       &pmx->functions[selector].num_groups,
> +					       &group_ids);
> +	if (ret) {
> +		dev_err(pmx->dev, "Unable to get function groups, err %d", ret);
> +		return ret;
> +	}
> +
> +	*num_groups = pmx->functions[selector].num_groups;
> +	if (!*num_groups)
> +		return -EINVAL;
> +
> +	pmx->functions[selector].groups =
> +		devm_kcalloc(pmx->dev, *num_groups,
> +			     sizeof(*pmx->functions[selector].groups),
> +			     GFP_KERNEL);
> +	if (!pmx->functions[selector].groups)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < *num_groups; i++) {
> +		pmx->functions[selector].groups[i] =
> +			pinctrl_scmi_get_group_name(pmx->pctldev,
> +						    group_ids[i]);
> +		if (!pmx->functions[selector].groups[i]) {
> +			ret = -ENOMEM;
> +			goto error;
> +		}
> +	}
> +
> +	*groups = (const char * const *)pmx->functions[selector].groups;
> +
> +	return 0;
> +
> +error:
> +	kfree(pmx->functions[selector].groups);

devm_kfree ?

> +
> +	return ret;
> +}
> +
> +static int pinctrl_scmi_func_set_mux(struct pinctrl_dev *pctldev,
> +				     unsigned int selector, unsigned int group)
> +{
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph)
> +		return -EINVAL;
> +
> +	return pinctrl_ops->set_mux(pmx->ph, selector, group);
> +}
> +
> +static int pinctrl_scmi_request(struct pinctrl_dev *pctldev,
> +				unsigned int offset)
> +{
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph)
> +		return -EINVAL;
> +
> +	return pinctrl_ops->request_pin(pmx->ph, offset);
> +}
> +
> +static int pinctrl_scmi_free(struct pinctrl_dev *pctldev, unsigned int offset)
> +{
> +	struct scmi_pinctrl *pmx;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph)
> +		return -EINVAL;
> +
> +	return pinctrl_ops->free_pin(pmx->ph, offset);
> +}
> +
> +static const struct pinmux_ops pinctrl_scmi_pinmux_ops = {
> +	.request = pinctrl_scmi_request,
> +	.free = pinctrl_scmi_free,
> +	.get_functions_count = pinctrl_scmi_get_functions_count,
> +	.get_function_name = pinctrl_scmi_get_function_name,
> +	.get_function_groups = pinctrl_scmi_get_function_groups,
> +	.set_mux = pinctrl_scmi_func_set_mux,
> +};
> +
> +static int pinctrl_scmi_pinconf_get(struct pinctrl_dev *pctldev,
> +				    unsigned int _pin,
> +				    unsigned long *config)
> +{
> +	int ret;
> +	struct scmi_pinctrl *pmx;
> +	enum pin_config_param config_type;
> +	unsigned long config_value;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph || !config)
> +		return -EINVAL;
> +
> +	config_type = pinconf_to_config_param(*config);
> +
> +	ret = pinctrl_ops->get_config(pmx->ph, _pin, PIN_TYPE, config_type,
> +				      (u32 *)&config_value);
> +	if (ret)
> +		return ret;
> +
> +	*config = pinconf_to_config_packed(config_type, config_value);
> +
> +	return 0;
> +}
> +
> +static int pinctrl_scmi_pinconf_set(struct pinctrl_dev *pctldev,
> +				    unsigned int _pin,
> +				    unsigned long *configs,
> +				    unsigned int num_configs)
> +{
> +	int i, ret;
> +	struct scmi_pinctrl *pmx;
> +	enum pin_config_param config_type;
> +	unsigned long config_value;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph || !configs || num_configs == 0)
> +		return -EINVAL;
> +
> +	for (i = 0; i < num_configs; i++) {
> +		config_type = pinconf_to_config_param(configs[i]);
> +		config_value = pinconf_to_config_argument(configs[i]);
> +
> +		ret = pinctrl_ops->set_config(pmx->ph, _pin, PIN_TYPE, config_type,
> +					      config_value);
> +		if (ret) {
> +			dev_err(pmx->dev, "Error parsing config %ld\n",
> +				configs[i]);
> +			break;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int pinctrl_scmi_pinconf_group_set(struct pinctrl_dev *pctldev,
> +					  unsigned int group,
> +					  unsigned long *configs,
> +					  unsigned int num_configs)
> +{
> +	int i, ret;
> +	struct scmi_pinctrl *pmx;
> +	enum pin_config_param config_type;
> +	unsigned long config_value;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph || !configs || num_configs == 0)
> +		return -EINVAL;
> +
> +	for (i = 0; i < num_configs; i++) {
> +		config_type = pinconf_to_config_param(configs[i]);
> +		config_value = pinconf_to_config_argument(configs[i]);
> +
> +		ret = pinctrl_ops->set_config(pmx->ph, group, GROUP_TYPE,
> +					      config_type, config_value);
> +		if (ret) {
> +			dev_err(pmx->dev, "Error parsing config = %ld",
> +				configs[i]);
> +			break;
> +		}
> +	}
> +
> +	return ret;
> +};
> +
> +static int pinctrl_scmi_pinconf_group_get(struct pinctrl_dev *pctldev,
> +					  unsigned int _pin,
> +					  unsigned long *config)
> +{
> +	int ret;
> +	struct scmi_pinctrl *pmx;
> +	enum pin_config_param config_type;
> +	unsigned long config_value;
> +
> +	if (!pctldev)
> +		return -EINVAL;
> +
> +	pmx = pinctrl_dev_get_drvdata(pctldev);
> +
> +	if (!pmx || !pmx->ph || !config)
> +		return -EINVAL;
> +
> +	config_type = pinconf_to_config_param(*config);
> +
> +	ret = pinctrl_ops->get_config(pmx->ph, _pin, GROUP_TYPE,
> +				      config_type, (u32 *)&config_value);
> +	if (ret)
> +		return ret;
> +
> +	*config = pinconf_to_config_packed(config_type, config_value);
> +
> +	return 0;
> +}
> +
> +static const struct pinconf_ops pinctrl_scmi_pinconf_ops = {
> +	.is_generic = true,
> +	.pin_config_get = pinctrl_scmi_pinconf_get,
> +	.pin_config_set = pinctrl_scmi_pinconf_set,
> +	.pin_config_group_set = pinctrl_scmi_pinconf_group_set,
> +	.pin_config_group_get = pinctrl_scmi_pinconf_group_get,
> +	.pin_config_config_dbg_show = pinconf_generic_dump_config,
> +};
> +
> +static int pinctrl_scmi_get_pins(struct scmi_pinctrl *pmx,
> +				 unsigned int *nr_pins,
> +				 const struct pinctrl_pin_desc **pins)
> +{
> +	int ret, i;
> +
> +	if (!pmx || !pmx->ph)
> +		return -EINVAL;
> +
> +	if (!pins || !nr_pins)
> +		return -EINVAL;
> +
> +	if (pmx->nr_pins) {
> +		*pins = pmx->pins;
> +		*nr_pins = pmx->nr_pins;
> +		return 0;
> +	}
> +
> +	*nr_pins = pinctrl_ops->get_count(pmx->ph, PIN_TYPE);
> +
> +	pmx->nr_pins = *nr_pins;
> +	pmx->pins = devm_kmalloc_array(pmx->dev, *nr_pins, sizeof(*pmx->pins),
> +				       GFP_KERNEL);
> +	if (!pmx->pins)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < *nr_pins; i++) {
> +		pmx->pins[i].number = i;
> +		ret = pinctrl_ops->get_name(pmx->ph, i, PIN_TYPE,
> +					    &pmx->pins[i].name);
> +		if (ret) {
> +			dev_err(pmx->dev, "Can't get name for pin %d: rc %d",
> +				i, ret);
> +			goto err;
> +		}
> +	}
> +
> +	*pins = pmx->pins;
> +	dev_dbg(pmx->dev, "got pins %d", *nr_pins);
> +
> +	return 0;
> + err:
> +	kfree(pmx->pins);
devm_kfree ? but anyway when this fails it will trigger the _probe to
fail so all devres will be released..so not needed probably at the end.

> +	pmx->nr_pins = 0;
> +
> +	return ret;
> +}
> +
> +static const struct scmi_device_id scmi_id_table[] = {
> +	{ SCMI_PROTOCOL_PINCTRL, "pinctrl" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(scmi, scmi_id_table);
> +
> +static int scmi_pinctrl_probe(struct scmi_device *sdev)
> +{
> +	int ret;
> +	struct scmi_pinctrl *pmx;
> +	const struct scmi_handle *handle;
> +	struct scmi_protocol_handle *ph;
> +
> +	if (!sdev || !sdev->handle)
> +		return -EINVAL;
> +
> +	handle = sdev->handle;
> +
> +	pinctrl_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PINCTRL,
> +						&ph);
> +	if (IS_ERR(pinctrl_ops))
> +		return PTR_ERR(pinctrl_ops);
> +
> +	pmx = devm_kzalloc(&sdev->dev, sizeof(*pmx), GFP_KERNEL);
> +	if (!pmx)
> +		return -ENOMEM;
> +
> +	pmx->ph = ph;
> +
> +	pmx->dev = &sdev->dev;
> +	pmx->pctl_desc.name = DRV_NAME;
> +	pmx->pctl_desc.owner = THIS_MODULE;
> +	pmx->pctl_desc.pctlops = &pinctrl_scmi_pinctrl_ops;
> +	pmx->pctl_desc.pmxops = &pinctrl_scmi_pinmux_ops;
> +	pmx->pctl_desc.confops = &pinctrl_scmi_pinconf_ops;
> +
> +	ret = pinctrl_scmi_get_pins(pmx, &pmx->pctl_desc.npins,
> +				    &pmx->pctl_desc.pins);
> +	if (ret)
> +		goto clean;
> +
> +	ret = devm_pinctrl_register_and_init(&sdev->dev, &pmx->pctl_desc, pmx,
> +					     &pmx->pctldev);
> +	if (ret) {
> +		dev_err(&sdev->dev, "could not register: %i\n", ret);
> +		goto clean;
> +	}
> +
> +	pmx->nr_functions = pinctrl_scmi_get_functions_count(pmx->pctldev);
> +	pmx->nr_groups = pinctrl_scmi_get_groups_count(pmx->pctldev);
> +
> +	if (pmx->nr_functions) {
> +		pmx->functions =
> +			devm_kcalloc(&sdev->dev, pmx->nr_functions,
> +				     sizeof(*pmx->functions),
> +				     GFP_KERNEL);
> +		if (!pmx->functions) {
> +			ret = -ENOMEM;
> +			goto clean;
> +		}
> +	}
> +
> +	if (pmx->nr_groups) {
> +		pmx->groups =
> +			devm_kcalloc(&sdev->dev, pmx->nr_groups,
> +				     sizeof(*pmx->groups),
> +				     GFP_KERNEL);
> +		if (!pmx->groups) {
> +			ret = -ENOMEM;
> +			goto clean;
> +		}
> +	}
> +
> +	return pinctrl_enable(pmx->pctldev);
> +
> +clean:
> +	if (pmx) {
> +		kfree(pmx->functions);
> +		kfree(pmx->groups);
> +	}
> +
> +	kfree(pmx);

All of these are devres allocated...it does not seem to me that they
require explicit freeing on the _probe() failure path.
(indeed you dont need even a .remove function)

Thanks,
Cristian

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