[PATCH v2 2/3] phy: Add driver for ST-Ericsson AB8500 USB PHY

[Jaehoon Chung]

On 7/9/21 3:33 AM, Stephan Gerhold wrote:
> The AB8500 PMIC contains an USB PHY that needs to be set up in
> device or host mode to make USB work properly. Add a simple driver
> for the generic PHY uclass that allows enabling it.
> 
> The if (CONFIG_IS_ENABLED(USB_MUSB_HOST)) might be a bit strange.
> The USB PHY must be configured in either host or device mode and
> somehow the USB PHY driver must be made aware of the mode.
> 
> Actually, the MUSB driver used together with this PHY does not
> support dynamic selection of host/device mode in U-Boot at the moment.
> Therefore, one very simple approach that works fine is to select
> the mode to configure at compile time. When the MUSB driver is
> configured in host mode the PHY is configured in host mode, and
> similarly when the MUSB driver is configured in device/gadget mode.
> 
> Reviewed-by: Linus Walleij <linus.walleij at linaro.org>
> Signed-off-by: Stephan Gerhold <stephan at gerhold.net>

Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>

Best Regards,
Jaehoon Chung

> ---
> 
> Changes in v2:
> - Assign AB8500_BIT_PHY_CTRL_DEVICE_EN by default and only replace
>   it with AB8500_BIT_PHY_CTRL_HOST_EN if needed (Jaehoon Chung)
> 
> Better suggestions to make the USB PHY driver aware of the mode
> are very welcome. :) I'm not sure it's worth it though, the compile
> time selection is not ideal but it does the job just fine for now.
> 
> ---
>  drivers/phy/Kconfig          |  6 +++++
>  drivers/phy/Makefile         |  1 +
>  drivers/phy/phy-ab8500-usb.c | 52 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 59 insertions(+)
>  create mode 100644 drivers/phy/phy-ab8500-usb.c
> 
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> index 008186a10d..92c74b9d0b 100644
> --- a/drivers/phy/Kconfig
> +++ b/drivers/phy/Kconfig
> @@ -64,6 +64,12 @@ config MIPI_DPHY_HELPERS
>  	help
>  	  Provides a number of helpers a core functions for MIPI D-PHY drivers.
>  
> +config AB8500_USB_PHY
> +	bool "AB8500 USB PHY Driver"
> +	depends on PHY && PMIC_AB8500
> +	help
> +	  Support for the USB OTG PHY in ST-Ericsson AB8500.
> +
>  config BCM6318_USBH_PHY
>  	bool "BCM6318 USBH PHY support"
>  	depends on PHY && ARCH_BMIPS
> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> index 3c4a673a83..bf03d05d9b 100644
> --- a/drivers/phy/Makefile
> +++ b/drivers/phy/Makefile
> @@ -6,6 +6,7 @@
>  obj-$(CONFIG_$(SPL_)PHY) += phy-uclass.o
>  obj-$(CONFIG_$(SPL_)NOP_PHY) += nop-phy.o
>  obj-$(CONFIG_MIPI_DPHY_HELPERS) += phy-core-mipi-dphy.o
> +obj-$(CONFIG_AB8500_USB_PHY) += phy-ab8500-usb.o
>  obj-$(CONFIG_BCM6318_USBH_PHY) += bcm6318-usbh-phy.o
>  obj-$(CONFIG_BCM6348_USBH_PHY) += bcm6348-usbh-phy.o
>  obj-$(CONFIG_BCM6358_USBH_PHY) += bcm6358-usbh-phy.o
> diff --git a/drivers/phy/phy-ab8500-usb.c b/drivers/phy/phy-ab8500-usb.c
> new file mode 100644
> index 0000000000..0e04595717
> --- /dev/null
> +++ b/drivers/phy/phy-ab8500-usb.c
> @@ -0,0 +1,52 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/* Copyright (C) 2019 Stephan Gerhold */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <generic-phy.h>
> +#include <linux/bitops.h>
> +#include <power/pmic.h>
> +#include <power/ab8500.h>
> +
> +#define AB8500_USB_PHY_CTRL_REG			AB8500_USB(0x8A)
> +#define AB8500_BIT_PHY_CTRL_HOST_EN		BIT(0)
> +#define AB8500_BIT_PHY_CTRL_DEVICE_EN		BIT(1)
> +#define AB8500_USB_PHY_CTRL_MASK		(AB8500_BIT_PHY_CTRL_HOST_EN |\
> +						 AB8500_BIT_PHY_CTRL_DEVICE_EN)
> +
> +static int ab8500_usb_phy_power_on(struct phy *phy)
> +{
> +	struct udevice *dev = phy->dev;
> +	uint set = AB8500_BIT_PHY_CTRL_DEVICE_EN;
> +
> +	if (CONFIG_IS_ENABLED(USB_MUSB_HOST))
> +		set = AB8500_BIT_PHY_CTRL_HOST_EN;
> +
> +	return pmic_clrsetbits(dev->parent, AB8500_USB_PHY_CTRL_REG,
> +			       AB8500_USB_PHY_CTRL_MASK, set);
> +}
> +
> +static int ab8500_usb_phy_power_off(struct phy *phy)
> +{
> +	struct udevice *dev = phy->dev;
> +
> +	return pmic_clrsetbits(dev->parent, AB8500_USB_PHY_CTRL_REG,
> +			       AB8500_USB_PHY_CTRL_MASK, 0);
> +}
> +
> +struct phy_ops ab8500_usb_phy_ops = {
> +	.power_on = ab8500_usb_phy_power_on,
> +	.power_off = ab8500_usb_phy_power_off,
> +};
> +
> +static const struct udevice_id ab8500_usb_phy_ids[] = {
> +	{ .compatible = "stericsson,ab8500-usb" },
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(ab8500_usb_phy) = {
> +	.name = "ab8500_usb_phy",
> +	.id = UCLASS_PHY,
> +	.of_match = ab8500_usb_phy_ids,
> +	.ops = &ab8500_usb_phy_ops,
> +};
>