Re: [PATCH 2/5] phy: iproc-mdio: Initial iProc MDC/MDIO support

[Kishon Vijay Abraham I <kishon@ti.com>]

Hi,

On Wednesday 20 May 2015 06:53 AM, Ray Jui wrote:
> This adds the support for the iProc MDC/MDIO interface. Multiple iProc
> SoCs contain the MDC/MDIO interface that can be used for the host to
> communicate with various Serdes/PHYs including Ethernet, PCIe, USB, etc.

the term phy used in this driver is misleading. It's not a PHY actually.
This sounds more like a bus driver to me and should be present in drivers/bus?

Thanks
Kishon
>
> Signed-off-by: Ray Jui <rjui@broadcom.com>
> Reviewed-by: Arun Parameswaran <aparames@broadcom.com>
> Reviewed-by: JD (Jiandong) Zheng <jdzheng@broadcom.com>
> Reviewed-by: Scott Branden <sbranden@broadcom.com>
> ---
>   drivers/phy/Kconfig                |   12 ++
>   drivers/phy/Makefile               |    1 +
>   drivers/phy/phy-iproc-mdio.c       |  249 ++++++++++++++++++++++++++++++++++++
>   include/linux/phy/iproc_mdio_phy.h |   22 ++++
>   4 files changed, 284 insertions(+)
>   create mode 100644 drivers/phy/phy-iproc-mdio.c
>   create mode 100644 include/linux/phy/iproc_mdio_phy.h
>
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> index a53bd5b..2664285 100644
> --- a/drivers/phy/Kconfig
> +++ b/drivers/phy/Kconfig
> @@ -52,6 +52,18 @@ config PHY_EXYNOS_MIPI_VIDEO
>   	  Support for MIPI CSI-2 and MIPI DSI DPHY found on Samsung S5P
>   	  and EXYNOS SoCs.
>
> +config PHY_IPROC_MDIO
> +	bool "Broadcom iProc MDC/MDIO driver"
> +	depends on ARCH_BCM_IPROC
> +	default ARCH_BCM_IPROC
> +	help
> +	  Enable this to support the iProc generic MDC/MDIO interface found
> +	  in various iProc based SoCs. The generic MDC/MDIO interface can be
> +	  used to communicate with various types of Serdes/PHYs including
> +	  Ethernet, PCIe, USB, and etc.
> +
> +	  If unsure, say N.
> +
>   config PHY_MVEBU_SATA
>   	def_bool y
>   	depends on ARCH_DOVE || MACH_DOVE || MACH_KIRKWOOD
> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> index f126251..d989dd7b 100644
> --- a/drivers/phy/Makefile
> +++ b/drivers/phy/Makefile
> @@ -13,6 +13,7 @@ obj-$(CONFIG_PHY_EXYNOS_MIPI_VIDEO)	+= phy-exynos-mipi-video.o
>   obj-$(CONFIG_PHY_MVEBU_SATA)		+= phy-mvebu-sata.o
>   obj-$(CONFIG_PHY_MIPHY28LP) 		+= phy-miphy28lp.o
>   obj-$(CONFIG_PHY_MIPHY365X)		+= phy-miphy365x.o
> +obj-$(CONFIG_PHY_IPROC_MDIO)		+= phy-iproc-mdio.o
>   obj-$(CONFIG_PHY_RCAR_GEN2)		+= phy-rcar-gen2.o
>   obj-$(CONFIG_OMAP_CONTROL_PHY)		+= phy-omap-control.o
>   obj-$(CONFIG_OMAP_USB2)			+= phy-omap-usb2.o
> diff --git a/drivers/phy/phy-iproc-mdio.c b/drivers/phy/phy-iproc-mdio.c
> new file mode 100644
> index 0000000..a37e92f
> --- /dev/null
> +++ b/drivers/phy/phy-iproc-mdio.c
> @@ -0,0 +1,249 @@
> +/*
> + * Copyright (C) 2015 Broadcom Corporation
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/phy/iproc_mdio_phy.h>
> +
> +#define MDIO_TIMEOUT_MSEC             10
> +
> +#define MDC_CTRL_OFFSET               0x000
> +
> +#define MDC_CTRL_DIV_SHIFT            0
> +#define MDC_CTRL_DIV_WIDTH            7
> +#define MDC_MAX_DIV                   (BIT(MDC_CTRL_DIV_WIDTH) - 1)
> +#define MDC_CTRL_PRE_SHIFT            7
> +#define MDC_CTRL_BUSY_SHIFT           8
> +#define MDC_CTRL_EXT_SHIFT            9
> +#define MDC_CTRL_BTP_SHIFT            10
> +
> +#define MDC_DATA_OFFSET               0x004
> +
> +#define MDC_DATA_SHIFT                0
> +#define MDC_DATA_MASK                 0xffff
> +
> +#define MDC_DATA_TA_SHIFT             16
> +#define MDC_DATA_TA_VAL               2
> +
> +#define MDC_DATA_RA_SHIFT             18
> +#define MDC_DATA_RA_WIDTH             5
> +#define MDC_MAX_RA                    (BIT(MDC_DATA_RA_WIDTH) - 1)
> +
> +#define MDC_DATA_PA_SHIFT             23
> +#define MDC_DATA_PA_WIDTH             5
> +#define MDC_MAX_PA                    (BIT(MDC_DATA_PA_WIDTH) - 1)
> +
> +#define MDC_DATA_OP_SHIFT             28
> +#define MDC_DATA_OP_WRITE             1
> +#define MDC_DATA_OP_READ              2
> +
> +#define MDC_DATA_SB_SHIFT             30
> +
> +/**
> + * struct iproc_mdc - iProc MDC/MDIO device
> + * @dev: pointer to device
> + * @base: MDC controller register base pointer
> + * @lock: mutex to protect access to the MDC device
> + * @is_ready: flag to indicate the driver has been initialized and is ready for
> + * use
> + */
> +struct iproc_mdc {
> +	struct device *dev;
> +	void __iomem *base;
> +	struct mutex lock;
> +	bool is_ready;
> +};
> +
> +static struct iproc_mdc iproc_mdc;
> +
> +static inline int iproc_mdio_check_params(unsigned clk_div, unsigned pa,
> +					  unsigned ra)
> +{
> +	if (clk_div > MDC_MAX_DIV || pa > MDC_MAX_PA || ra > MDC_MAX_RA)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static inline int iproc_mdio_wait_for_idle(void __iomem *base)
> +{
> +	u32 val;
> +	unsigned long timeout = jiffies + msecs_to_jiffies(MDIO_TIMEOUT_MSEC);
> +
> +	while (!time_after(jiffies, timeout)) {
> +		val = readl(base + MDC_CTRL_OFFSET);
> +		if ((val & BIT(MDC_CTRL_BUSY_SHIFT)) == 0)
> +			return 0;
> +
> +		cpu_relax();
> +	}
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static inline void iproc_mdio_config_clk(void __iomem *base, unsigned clk_div)
> +{
> +	u32 val;
> +
> +	val = (clk_div << MDC_CTRL_DIV_SHIFT) | BIT(MDC_CTRL_PRE_SHIFT);
> +	writel(val, base + MDC_CTRL_OFFSET);
> +}
> +
> +static int iproc_mdio_read_write(void __iomem *base, bool dir_is_write,
> +				 unsigned clk_div, unsigned pa, unsigned ra,
> +				 u16 *data)
> +{
> +	int ret;
> +	u32 val;
> +
> +	ret = iproc_mdio_check_params(clk_div, pa, ra);
> +	if (ret)
> +		return ret;
> +
> +	ret = iproc_mdio_wait_for_idle(base);
> +	if (ret)
> +		return ret;
> +
> +	iproc_mdio_config_clk(base, clk_div);
> +
> +	ret = iproc_mdio_wait_for_idle(base);
> +	if (ret)
> +		return ret;
> +
> +	val = (MDC_DATA_TA_VAL << MDC_DATA_TA_SHIFT) |
> +		(ra << MDC_DATA_RA_SHIFT) |
> +		(pa << MDC_DATA_PA_SHIFT) |
> +		BIT(MDC_DATA_SB_SHIFT);
> +
> +	if (dir_is_write) {
> +		val |= (MDC_DATA_OP_WRITE << MDC_DATA_OP_SHIFT);
> +		val |= ((u32)(*data) & MDC_DATA_MASK);
> +	} else {
> +		val |= (MDC_DATA_OP_READ << MDC_DATA_OP_SHIFT);
> +	}
> +
> +	writel(val, base + MDC_DATA_OFFSET);
> +
> +	ret = iproc_mdio_wait_for_idle(base);
> +	if (ret)
> +		return ret;
> +
> +	if (!dir_is_write) {
> +		val = readl(base + MDC_DATA_OFFSET) & MDC_DATA_MASK;
> +		*data = (u16)val;
> +	}
> +
> +	return 0;
> +}
> +
> +
> +/**
> + * iproc_mdio_read() - read from a PHY register through the MDC interface
> + *
> + * @clk_div: MDC clock divisor
> + * @phy_addr: MDC PHY address
> + * @reg_addr: PHY register address
> + * @data: pointer to the memory where data will be stored
> + */
> +int iproc_mdio_read(unsigned clk_div, unsigned phy_addr, unsigned reg_addr,
> +		    u16 *data)
> +{
> +	int ret;
> +	struct iproc_mdc *mdc = &iproc_mdc;
> +
> +	if (!mdc->is_ready)
> +		return -ENODEV;
> +
> +	mutex_lock(&mdc->lock);
> +	ret = iproc_mdio_read_write(mdc->base, false, clk_div, phy_addr,
> +				    reg_addr, data);
> +	if (ret)
> +		dev_err(mdc->dev, "mdio read failed\n");
> +	mutex_unlock(&mdc->lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(iproc_mdio_read);
> +
> +/**
> + * iproc_mdio_write() - write to a PHY register through the MDC interface
> + *
> + * @clk_div: MDC clock divisor
> + * @phy_addr: MDC PHY address
> + * @reg_addr: PHY register address
> + * @data: data value to be written to the PHY register
> + */
> +int iproc_mdio_write(unsigned clk_div, unsigned phy_addr, unsigned reg_addr,
> +		     u16 data)
> +{
> +	int ret;
> +	struct iproc_mdc *mdc = &iproc_mdc;
> +
> +	if (!mdc->is_ready)
> +		return -ENODEV;
> +
> +	mutex_lock(&mdc->lock);
> +	ret = iproc_mdio_read_write(mdc->base, true, clk_div, phy_addr,
> +				    reg_addr, &data);
> +	if (ret)
> +		dev_err(mdc->dev, "mdio write failed\n");
> +	mutex_unlock(&mdc->lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(iproc_mdio_write);
> +
> +static int iproc_mdio_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct iproc_mdc *mdc = &iproc_mdc;
> +	struct resource *res;
> +
> +	mdc->dev = dev;
> +	mutex_init(&mdc->lock);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	mdc->base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(mdc->base))
> +		return PTR_ERR(mdc->base);
> +
> +	mdc->is_ready = true;
> +	return 0;
> +}
> +
> +static const struct of_device_id iproc_mdio_match_table[] = {
> +	{ .compatible = "brcm,iproc-mdio" },
> +	{ }
> +};
> +
> +static struct platform_driver iproc_mdio_driver = {
> +	.driver = {
> +		.name = "iproc-mdio",
> +		.of_match_table = iproc_mdio_match_table,
> +		.suppress_bind_attrs = true,
> +	},
> +	.probe	= iproc_mdio_probe,
> +};
> +
> +static int __init iproc_mdio_init(void)
> +{
> +	return platform_driver_register(&iproc_mdio_driver);
> +}
> +arch_initcall_sync(iproc_mdio_init);
> +
> +MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
> +MODULE_DESCRIPTION("Broadcom iPROC MDC/MDIO driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/phy/iproc_mdio_phy.h b/include/linux/phy/iproc_mdio_phy.h
> new file mode 100644
> index 0000000..d3e88ce
> --- /dev/null
> +++ b/include/linux/phy/iproc_mdio_phy.h
> @@ -0,0 +1,22 @@
> +/*
> + * Copyright (C) 2015 Broadcom Corporation
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __IPROC_MDIO_PHY_H
> +#define __IPROC_MDIO_PHY_H
> +
> +int iproc_mdio_read(unsigned clk_div, unsigned phy_addr, unsigned reg_addr,
> +		    u16 *data);
> +int iproc_mdio_write(unsigned clk_div, unsigned phy_addr, unsigned reg_addr,
> +		     u16 data);
> +
> +#endif /* __IPROC_MDIO_PHY_H */
>