Message-ID: <20251127022841.743277-1-jianhui.lee@canonical.com>
Date: Thu, 27 Nov 2025 10:28:41 +0800
From: Jian Hui Lee <jianhui.lee@...onical.com>
To: tommaso.merciai.xr@...renesas.com
Cc: andi.shyti@...nel.org,
	arnd@...db.de,
	biju.das.jz@...renesas.com,
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	tomm.merciai@...il.com,
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	yoshihiro.shimoda.uh@...esas.com
Subject: Re: [PATCH v4 06/22] mux: Add driver for Renesas RZ/V2H USB VBUS_SEL mux

On Fri, Nov 21, 2025 at 04:11:55PM +0100, Tommaso Merciai wrote:
> As per the RZ/V2H(P) HW manual, VBUSEN can be controlled by the VBUS_SEL
> bit of the VBENCTL Control Register. This register is mapped in the
> reset framework. The reset driver expose this register as mux-controller
> and instantiates this driver. The consumer will use the mux API to
> control the VBUS_SEL bit.
> 
> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
> ---
> v3->v4:
>  - Removed mux_chip->dev.of_node not needed.
> 
> v2->v3:
>  - Added mux_chip->dev.of_node = dev->of_node->child as the mux-controller
>    is an internal node.
>  - Fixed auxiliary_device_id name.
>  - Get rdev using from platform_data.
>  - Drop struct auxiliary_device adev from reset_rzv2h_usb2phy_adev
>    as it is needed.
>  - Drop to_reset_rzv2h_usb2phy_adev() as it is not needed.
> 
> v1->v2:
>  - New patch
> 
>  drivers/mux/Kconfig                       | 10 +++
>  drivers/mux/Makefile                      |  2 +
>  drivers/mux/rzv2h-usb-vbus.c              | 97 +++++++++++++++++++++++
>  include/linux/reset/reset_rzv2h_usb2phy.h | 11 +++
>  4 files changed, 120 insertions(+)
>  create mode 100644 drivers/mux/rzv2h-usb-vbus.c
>  create mode 100644 include/linux/reset/reset_rzv2h_usb2phy.h
> 
> diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig
> index c68132e38138..604f625544ed 100644
> --- a/drivers/mux/Kconfig
> +++ b/drivers/mux/Kconfig
> @@ -59,4 +59,14 @@ config MUX_MMIO
>  	  To compile the driver as a module, choose M here: the module will
>  	  be called mux-mmio.
>  
> +config MUX_RZV2H_VBENCTL
> +	tristate "Renesas RZ/V2H USB VBUS mux driver"
> +	depends on RESET_RZV2H_USB2PHY || COMPILE_TEST
> +	depends on OF
> +	select REGMAP_MMIO
> +	select AUXILIARY_BUS
> +	default RESET_RZV2H_USB2PHY
> +	help
> +	  Support for VBUS mux implemented on Renesas RZ/V2H SoCs.
> +
>  endmenu
> diff --git a/drivers/mux/Makefile b/drivers/mux/Makefile
> index 6e9fa47daf56..9421660399af 100644
> --- a/drivers/mux/Makefile
> +++ b/drivers/mux/Makefile
> @@ -8,9 +8,11 @@ mux-adg792a-objs		:= adg792a.o
>  mux-adgs1408-objs		:= adgs1408.o
>  mux-gpio-objs			:= gpio.o
>  mux-mmio-objs			:= mmio.o
> +mux-rzv2h-usb-vbus-objs		:= rzv2h-usb-vbus.o
>  
>  obj-$(CONFIG_MULTIPLEXER)	+= mux-core.o
>  obj-$(CONFIG_MUX_ADG792A)	+= mux-adg792a.o
>  obj-$(CONFIG_MUX_ADGS1408)	+= mux-adgs1408.o
>  obj-$(CONFIG_MUX_GPIO)		+= mux-gpio.o
>  obj-$(CONFIG_MUX_MMIO)		+= mux-mmio.o
> +obj-$(CONFIG_MUX_RZV2H_VBENCTL)	+= mux-rzv2h-usb-vbus.o
> diff --git a/drivers/mux/rzv2h-usb-vbus.c b/drivers/mux/rzv2h-usb-vbus.c
> new file mode 100644
> index 000000000000..9513bc8f35ff
> --- /dev/null
> +++ b/drivers/mux/rzv2h-usb-vbus.c
> @@ -0,0 +1,97 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas RZ/V2H(P) USB2 VBUS_SEL mux driver
> + *
> + * Copyright (C) 2025 Renesas Electronics Corp.
> + */
> +
> +#include <linux/auxiliary_bus.h>
> +#include <linux/bitops.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/mux/driver.h>
> +#include <linux/of.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +#include <linux/reset/reset_rzv2h_usb2phy.h>
> +
> +#define RZV2H_VBENCTL		0xf0c
> +
> +struct mux_rzv2h_usb_vbus_priv {
> +	struct regmap_field *field;
> +};
> +
> +static int mux_rzv2h_usb_vbus_set(struct mux_control *mux, int state)
> +{
> +	struct mux_rzv2h_usb_vbus_priv *priv = mux_chip_priv(mux->chip);
> +
> +	return regmap_field_write(priv->field, state);
> +}
> +
> +static const struct mux_control_ops mux_rzv2h_usb_vbus_ops = {
> +	.set = mux_rzv2h_usb_vbus_set,
> +};
> +
> +static const struct regmap_config rzv2h_usb_vbus_regconf = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.max_register = RZV2H_VBENCTL,
> +};
> +
> +static int mux_rzv2h_usb_vbus_probe(struct auxiliary_device *adev,
> +				    const struct auxiliary_device_id *id)
> +{
> +	struct reset_rzv2h_usb2phy_adev *rdev = adev->dev.platform_data;
> +	struct mux_rzv2h_usb_vbus_priv *priv;
> +	struct device *dev = &adev->dev;
> +	struct mux_chip *mux_chip;
> +	struct regmap *regmap;
> +	struct reg_field reg_field = {
> +		.reg = RZV2H_VBENCTL,
> +		.lsb = 0,
> +		.msb = 0,
> +	};
> +	int ret;
> +
> +	regmap = devm_regmap_init_mmio(dev, rdev->base, &rzv2h_usb_vbus_regconf);
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*priv));
> +	if (IS_ERR(mux_chip))
> +		return PTR_ERR(mux_chip);
> +
> +	priv = mux_chip_priv(mux_chip);
> +
> +	priv->field = devm_regmap_field_alloc(dev, regmap, reg_field);
> +	if (IS_ERR(priv->field))
> +		return PTR_ERR(priv->field);
> +
> +	mux_chip->ops = &mux_rzv2h_usb_vbus_ops;
> +	mux_chip->mux[0].states = 2;
> +	mux_chip->mux[0].idle_state = MUX_IDLE_AS_IS;
> +
> +	ret = devm_mux_chip_register(dev, mux_chip);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to register mux chip\n");
> +
> +	return 0;
> +}
> +
> +static const struct auxiliary_device_id mux_rzv2h_usb_vbus_ids[] = {
> +	{ .name = "rzv2h_usb2phy_reset.vbus-sel-mux" },

hi Tommaso,
this string causes buffer overflow, could you help to check on it?

[   15.349036] strlen: detected buffer overflow: 33 byte read of buffer size 32
[   15.349083] WARNING: CPU: 0 PID: 518 at lib/string_helpers.c:1035 __fortify_report+0x64/0xc8
[   15.349110] Modules linked in: mux_rzv2h_usb_vbus(+) rcar_canfd(+) mtd sm4_ce(-) can_dev rz_dmac(+) pwm_rzg2l_gpt binfmt_misc dm_multipath efi_pstore nfnetlink ip_tables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor xor_neon raid6_pq raid1 raid0 linear rtc_isl1208 micrel phy_package mmc_block raa215300 rpmb_core dwmac_renesas_gbeth spi_rpc_if pcs_rzn1_miic stmmac_platform stmmac polyval_ce renesas_sdhi_internal_dmac renesas_usbhs ghash_ce panfrost udc_core pcs_xpcs renesas_sdhi_core reset_rzv2h_usb2phy gpu_sched tmio_mmc_core xhci_rcar_hcd ehci_platform sm4 phy_rzg3e_usb3 phy_rcar_gen3_usb2 rzv2m_usb3drd xhci_plat_hcd ohci_platform renesas_rpc_if i2c_riic gpio_regulator gpio_keys fixed aes_neon_bs aes_neon_blk aes_ce_blk aes_ce_cipher
[   15.349359] CPU: 0 UID: 0 PID: 518 Comm: (udev-worker) Not tainted 6.18.0-5.5 #3 PREEMPT(voluntary)
[   15.349371] Hardware name: Renesas SMARC EVK version 2 based on r9a09g047e57 (DT)
[   15.349380] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   15.349390] pc : __fortify_report+0x64/0xc8
[   15.349400] lr : __fortify_report+0x64/0xc8
[   15.349408] sp : ffff8000854fb830
[   15.349413] x29: ffff8000854fb830 x28: ffff80007c7a41d8 x27: ffff80007c7a4300
[   15.349430] x26: ffff800083c4d780 x25: 0000000000000000 x24: ffff0000c5de9de8
[   15.349446] x23: ffff800081d23b68 x22: ffff0000c004b200 x21: ffff0000ca6dd080
[   15.349462] x20: 0000000000000020 x19: ffff80007c7a6140 x18: ffff800084b870a8
[   15.349477] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[   15.349492] x14: 0000000000000000 x13: 323320657a697320 x12: 7265666675622066
[   15.349507] x11: 0000000000000000 x10: 0000000000000000 x9 : ffff800080208f0c
[   15.349522] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
[   15.349536] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
[   15.349550] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
[   15.349565] Call trace:
[   15.349572]  __fortify_report+0x64/0xc8 (P)
[   15.349583]  __fortify_panic+0x14/0x18
[   15.349595]  auxiliary_match_id+0xf8/0x110
[   15.349608]  auxiliary_match+0x28/0x60
[   15.349617]  __driver_attach+0x34/0x2a8
[   15.349629]  bus_for_each_dev+0x88/0x110
[   15.349639]  driver_attach+0x30/0x60
[   15.349649]  bus_add_driver+0x178/0x2d8
[   15.349658]  driver_register+0x74/0x178
[   15.349668]  __auxiliary_driver_register+0x7c/0x150
[   15.349677]  mux_rzv2h_usb_vbus_driver_init+0x34/0xfd0 [mux_rzv2h_usb_vbus]

> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(auxiliary, mux_rzv2h_usb_vbus_ids);
> +
> +static struct auxiliary_driver mux_rzv2h_usb_vbus_driver = {
> +	.name		= "vbus-sel-mux",
> +	.probe		= mux_rzv2h_usb_vbus_probe,
> +	.id_table	= mux_rzv2h_usb_vbus_ids,
> +};
> +module_auxiliary_driver(mux_rzv2h_usb_vbus_driver);
> +
> +MODULE_DESCRIPTION("RZ/V2H USB VBUS_SEL mux driver");
> +MODULE_AUTHOR("Tommaso Merciai <tommaso.merciai.xr@...renesas.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/reset/reset_rzv2h_usb2phy.h b/include/linux/reset/reset_rzv2h_usb2phy.h
> new file mode 100644
> index 000000000000..06247080a66c
> --- /dev/null
> +++ b/include/linux/reset/reset_rzv2h_usb2phy.h
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _RESET_RZV2H_USB2PHY_H
> +#define _RESET_RZV2H_USB2PHY_H
> +
> +#include <linux/auxiliary_bus.h>
> +
> +struct reset_rzv2h_usb2phy_adev {
> +	void __iomem *base;
> +};
> +
> +#endif
> -- 
> 2.43.0
> 
> 
> -- 
> linux-phy mailing list
> linux-phy@...ts.infradead.org
> https://lists.infradead.org/mailman/listinfo/linux-phy

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