Re: [PATCH/RESEND V4 3/3] ARM64 LPC: LPC driver implementation on Hip06

[Mark Rutland]

Hi,

I received an off-list v5 of this for some reason.

I have several concerns with this, but given there's evidently a v5, I
intend to wait until that is posted before I reply with my comments.

Thanks,
Mark.

On Tue, Nov 01, 2016 at 09:28:46PM +0800, zhichang.yuan wrote:
> On Hip06, the accesses to LPC peripherals work in an indirect way. A
> corresponding LPC driver configure some registers in LPC master at first, then
> the real accesses on LPC slave devices are finished by the LPC master, which
> is transparent to LPC driver.
> This patch implement the relevant driver for Hip06 LPC. Cooperating with
> indirect-IO, ipmi messages is in service without any changes on ipmi driver.
> 
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Signed-off-by: zhichang.yuan <yuanzhichang@xxxxxxxxxxxxx>
> Signed-off-by: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx>
> ---
>  .../arm/hisilicon/hisilicon-low-pin-count.txt      |  31 ++
>  MAINTAINERS                                        |   8 +
>  drivers/bus/Kconfig                                |   8 +
>  drivers/bus/Makefile                               |   1 +
>  drivers/bus/hisi_lpc.c                             | 501 +++++++++++++++++++++
>  5 files changed, 549 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
>  create mode 100644 drivers/bus/hisi_lpc.c
> 
> diff --git a/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt b/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> new file mode 100644
> index 0000000..e681419
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> @@ -0,0 +1,31 @@
> +Hisilicon Hip06 low-pin-count device
> +  Usually LPC controller is part of PCI host bridge, so the legacy ISA ports
> +  locate on LPC bus can be accessed direclty. But some SoCs have independent
> +  LPC controller, and access the legacy ports by triggering LPC I/O cycles.
> +  Hisilicon Hip06 implements this LPC device.
> +
> +Required properties:
> +- compatible: should be "hisilicon,low-pin-count"
> +- #address-cells: must be 2 which stick to the ISA/EISA binding doc.
> +- #size-cells: must be 1 which stick to the ISA/EISA binding doc.
> +- reg: base memory range where the register set for this device is mapped.
> +
> +Note:
> +  The node name before '@' must be "isa" to represent the binding stick to the
> +  ISA/EISA binding specification.
> +
> +Example:
> +
> +isa@a01b0000 {
> +	compatible = "hisilicom,low-pin-count";
> +	#address-cells = <2>;
> +	#size-cells = <1>;
> +	reg = <0x0 0xa01b0000 0x0 0x1000>;
> +
> +	ipmi0: bt@e4 {
> +		compatible = "ipmi-bt";
> +		device_type = "ipmi";
> +		reg = <0x01 0xe4 0x04>;
> +		status = "disabled";
> +	};
> +};
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 1cd38a7..7c69410 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5716,6 +5716,14 @@ F:	include/uapi/linux/if_hippi.h
>  F:	net/802/hippi.c
>  F:	drivers/net/hippi/
>  
> +HISILICON LPC BUS DRIVER
> +M:	Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>
> +L:	linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> +W:	http://www.hisilicon.com
> +S:	Maintained
> +F:	drivers/bus/hisi_lpc.c
> +F:	Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> +
>  HISILICON NETWORK SUBSYSTEM DRIVER
>  M:	Yisen Zhuang <yisen.zhuang@xxxxxxxxxx>
>  M:	Salil Mehta <salil.mehta@xxxxxxxxxx>
> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
> index 7010dca..a108abc 100644
> --- a/drivers/bus/Kconfig
> +++ b/drivers/bus/Kconfig
> @@ -64,6 +64,14 @@ config BRCMSTB_GISB_ARB
>  	  arbiter. This driver provides timeout and target abort error handling
>  	  and internal bus master decoding.
>  
> +config HISILICON_LPC
> +	bool "Workaround for nonstandard ISA I/O space on Hisilicon Hip0X"
> +	depends on (ARCH_HISI || COMPILE_TEST) && ARM64
> +	select ARM64_INDIRECT_PIO
> +	help
> +	  Driver needed for some legacy ISA devices attached to Low-Pin-Count
> +	  on Hisilicon Hip0X SoC.
> +
>  config IMX_WEIM
>  	bool "Freescale EIM DRIVER"
>  	depends on ARCH_MXC
> diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
> index c6cfa6b..10b4983 100644
> --- a/drivers/bus/Makefile
> +++ b/drivers/bus/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_ARM_CCI)		+= arm-cci.o
>  obj-$(CONFIG_ARM_CCN)		+= arm-ccn.o
>  
>  obj-$(CONFIG_BRCMSTB_GISB_ARB)	+= brcmstb_gisb.o
> +obj-$(CONFIG_HISILICON_LPC)	+= hisi_lpc.o
>  obj-$(CONFIG_IMX_WEIM)		+= imx-weim.o
>  obj-$(CONFIG_MIPS_CDMM)		+= mips_cdmm.o
>  obj-$(CONFIG_MVEBU_MBUS) 	+= mvebu-mbus.o
> diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
> new file mode 100644
> index 0000000..9f48a1a
> --- /dev/null
> +++ b/drivers/bus/hisi_lpc.c
> @@ -0,0 +1,501 @@
> +/*
> + * Copyright (C) 2016 Hisilicon Limited, All Rights Reserved.
> + * Author: Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>
> + * Author: Zou Rongrong <zourongrong@xxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/console.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_platform.h>
> +#include <linux/pci.h>
> +#include <linux/serial_8250.h>
> +#include <linux/slab.h>
> +
> +/*
> + * this bit set means each IO operation will target to different port address;
> + * 0 means repeatly IO operations will be sticked on the same port, such as BT;
> + */
> +#define FG_INCRADDR_LPC		0x02
> +
> +struct lpc_cycle_para {
> +	unsigned int opflags;
> +	unsigned int csize;/* the data length of each operation */
> +};
> +
> +struct hisilpc_dev {
> +	spinlock_t cycle_lock;
> +	void __iomem  *membase;
> +	struct extio_ops io_ops;
> +};
> +
> +
> +/* The maximum continous operations*/
> +#define LPC_MAX_OPCNT	16
> +/* only support IO data unit length is four at maximum */
> +#define LPC_MAX_DULEN	4
> +#if LPC_MAX_DULEN > LPC_MAX_OPCNT
> +#error "LPC.. MAX_DULEN must be not bigger than MAX_OPCNT!"
> +#endif
> +
> +#define LPC_REG_START		0x00/* start a new LPC cycle */
> +#define LPC_REG_OP_STATUS	0x04/* the current LPC status */
> +#define LPC_REG_IRQ_ST		0x08/* interrupt enable&status */
> +#define LPC_REG_OP_LEN		0x10/* how many LPC cycles each start */
> +#define LPC_REG_CMD		0x14/* command for the required LPC cycle */
> +#define LPC_REG_ADDR		0x20/* LPC target address */
> +#define LPC_REG_WDATA		0x24/* data to be written */
> +#define LPC_REG_RDATA		0x28/* data coming from peer */
> +
> +
> +/* The command register fields*/
> +#define LPC_CMD_SAMEADDR	0x08
> +#define LPC_CMD_TYPE_IO		0x00
> +#define LPC_CMD_WRITE		0x01
> +#define LPC_CMD_READ		0x00
> +/* the bit attribute is W1C. 1 represents OK. */
> +#define LPC_STAT_BYIRQ		0x02
> +
> +#define LPC_STATUS_IDLE		0x01
> +#define LPC_OP_FINISHED		0x02
> +
> +#define START_WORK		0x01
> +
> +/*
> + * The minimal waiting interval... Suggest it is not less than 10.
> + * Bigger value probably will lower the performance.
> + */
> +#define LPC_NSEC_PERWAIT	100
> +/*
> + * The maximum waiting time is about 128us.
> + * The fastest IO cycle time is about 390ns, but the worst case will wait
> + * for extra 256 lpc clocks, so (256 + 13) * 30ns = 8 us. The maximum
> + * burst cycles is 16. So, the maximum waiting time is about 128us under
> + * worst case.
> + * choose 1300 as the maximum.
> + */
> +#define LPC_MAX_WAITCNT		1300
> +/* About 10us. This is specfic for single IO operation, such as inb. */
> +#define LPC_PEROP_WAITCNT	100
> +
> +
> +static inline int wait_lpc_idle(unsigned char *mbase,
> +				unsigned int waitcnt) {
> +	u32 opstatus;
> +
> +	while (waitcnt--) {
> +		ndelay(LPC_NSEC_PERWAIT);
> +		opstatus = readl(mbase + LPC_REG_OP_STATUS);
> +		if (opstatus & LPC_STATUS_IDLE)
> +			return (opstatus & LPC_OP_FINISHED) ? 0 : (-EIO);
> +	}
> +	return -ETIME;
> +}
> +
> +
> +/**
> + * hisilpc_target_in - trigger a series of lpc cycles to read required data
> + *		  from target periperal.
> + * @pdev: pointer to hisi lpc device
> + * @para: some paramerters used to control the lpc I/O operations
> + * @ptaddr: the lpc I/O target port address
> + * @buf: where the read back data is stored
> + * @opcnt: how many I/O operations required in this calling
> + *
> + * only one byte data is read each I/O operation.
> + *
> + * Returns 0 on success, non-zero on fail.
> + *
> + */
> +static int hisilpc_target_in(struct hisilpc_dev *pdev,
> +				struct lpc_cycle_para *para,
> +				unsigned long ptaddr, unsigned char *buf,
> +				unsigned long opcnt)
> +{
> +	unsigned int cmd_word;
> +	unsigned int waitcnt;
> +	int retval;
> +	unsigned long flags;
> +	unsigned long cnt_per_trans;
> +
> +	if (!buf || !opcnt || !para || !para->csize || !pdev)
> +		return -EINVAL;
> +
> +	if (opcnt  > LPC_MAX_OPCNT)
> +		return -EINVAL;
> +
> +	cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_READ;
> +	waitcnt = (LPC_PEROP_WAITCNT);
> +	if (!(para->opflags & FG_INCRADDR_LPC)) {
> +		cmd_word |= LPC_CMD_SAMEADDR;
> +		waitcnt = LPC_MAX_WAITCNT;
> +	}
> +
> +	retval = 0;
> +	cnt_per_trans = (para->csize == 1) ? opcnt : para->csize;
> +	for (; opcnt && !retval; cnt_per_trans = para->csize) {
> +		/* whole operation must be atomic */
> +		spin_lock_irqsave(&pdev->cycle_lock, flags);
> +
> +		writel(cnt_per_trans, pdev->membase + LPC_REG_OP_LEN);
> +
> +		writel(cmd_word, pdev->membase + LPC_REG_CMD);
> +
> +		writel(ptaddr, pdev->membase + LPC_REG_ADDR);
> +
> +		writel(START_WORK, pdev->membase + LPC_REG_START);
> +
> +		/* whether the operation is finished */
> +		retval = wait_lpc_idle(pdev->membase, waitcnt);
> +		if (!retval) {
> +			opcnt -= cnt_per_trans;
> +			for (; cnt_per_trans--; buf++)
> +				*buf = readl(pdev->membase + LPC_REG_RDATA);
> +		}
> +
> +		spin_unlock_irqrestore(&pdev->cycle_lock, flags);
> +	}
> +
> +	return retval;
> +}
> +
> +/**
> + * hisilpc_target_out - trigger a series of lpc cycles to write required data
> + *		  to target periperal.
> + * @pdev: pointer to hisi lpc device
> + * @para: some paramerters used to control the lpc I/O operations
> + * @ptaddr: the lpc I/O target port address
> + * @buf: where the data to be written is stored
> + * @opcnt: how many I/O operations required
> + *
> + * only one byte data is read each I/O operation.
> + *
> + * Returns 0 on success, non-zero on fail.
> + *
> + */
> +static int hisilpc_target_out(struct hisilpc_dev *pdev,
> +				struct lpc_cycle_para *para,
> +				unsigned long ptaddr,
> +				const unsigned char *buf,
> +				unsigned long opcnt)
> +{
> +	unsigned int cmd_word;
> +	unsigned int waitcnt;
> +	int retval;
> +	unsigned long flags;
> +	unsigned long cnt_per_trans;
> +
> +	if (!buf || !opcnt || !para || !pdev)
> +		return -EINVAL;
> +
> +	if (opcnt > LPC_MAX_OPCNT)
> +		return -EINVAL;
> +	/* default is increasing address */
> +	cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_WRITE;
> +	waitcnt = (LPC_PEROP_WAITCNT);
> +	if (!(para->opflags & FG_INCRADDR_LPC)) {
> +		cmd_word |= LPC_CMD_SAMEADDR;
> +		waitcnt = LPC_MAX_WAITCNT;
> +	}
> +
> +	retval = 0;
> +	cnt_per_trans = (para->csize == 1) ? opcnt : para->csize;
> +	for (; opcnt && !retval; cnt_per_trans = para->csize) {
> +		spin_lock_irqsave(&pdev->cycle_lock, flags);
> +
> +		writel(cnt_per_trans, pdev->membase + LPC_REG_OP_LEN);
> +		opcnt -= cnt_per_trans;
> +		for (; cnt_per_trans--; buf++)
> +			writel(*buf, pdev->membase + LPC_REG_WDATA);
> +
> +		writel(cmd_word, pdev->membase + LPC_REG_CMD);
> +
> +		writel(ptaddr, pdev->membase + LPC_REG_ADDR);
> +
> +		writel(START_WORK, pdev->membase + LPC_REG_START);
> +
> +		/* whether the operation is finished */
> +		retval = wait_lpc_idle(pdev->membase, waitcnt);
> +
> +		spin_unlock_irqrestore(&pdev->cycle_lock, flags);
> +	}
> +
> +	return retval;
> +}
> +
> +
> +/**
> + * hisilpc_comm_in - read/input the data from the I/O peripheral through LPC.
> + * @devobj: pointer to the device information relevant to LPC controller.
> + * @ptaddr: the target I/O port address.
> + * @dlen: the data length required to read from the target I/O port.
> + *
> + * when succeed, the data read back is stored in buffer pointed by inbuf.
> + * For inb, return the data read from I/O or -1 when error occur.
> + */
> +static u64 hisilpc_comm_in(void *devobj, unsigned long ptaddr, size_t dlen)
> +{
> +	struct hisilpc_dev *lpcdev;
> +	struct lpc_cycle_para iopara;
> +	u32 rd_data;
> +	unsigned char *newbuf;
> +	int ret = 0;
> +
> +	if (!devobj || !dlen || dlen > LPC_MAX_DULEN ||	(dlen & (dlen - 1)))
> +		return -1;
> +
> +	/* the local buffer must be enough for one data unit */
> +	if (sizeof(rd_data) < dlen)
> +		return -1;
> +
> +	newbuf = (unsigned char *)&rd_data;
> +
> +	lpcdev = (struct hisilpc_dev *)devobj;
> +
> +	iopara.opflags = FG_INCRADDR_LPC;
> +	iopara.csize = dlen;
> +
> +	ret = hisilpc_target_in(lpcdev, &iopara, ptaddr, newbuf, dlen);
> +	if (ret)
> +		return -1;
> +
> +	return le32_to_cpu(rd_data);
> +}
> +
> +/**
> + * hisilpc_comm_out - write/output the data whose maximal length is four bytes to
> + *		the I/O peripheral through LPC.
> + * @devobj: pointer to the device information relevant to LPC controller.
> + * @outval: a value to be outputed from caller, maximum is four bytes.
> + * @ptaddr: the target I/O port address.
> + * @dlen: the data length required writing to the target I/O port .
> + *
> + * This function is corresponding to out(b,w,l) only
> + *
> + */
> +static void hisilpc_comm_out(void *devobj, unsigned long ptaddr,
> +				u32 outval, size_t dlen)
> +{
> +	struct hisilpc_dev *lpcdev;
> +	struct lpc_cycle_para iopara;
> +	const unsigned char *newbuf;
> +
> +	if (!devobj || !dlen || dlen > LPC_MAX_DULEN)
> +		return;
> +
> +	if (sizeof(outval) < dlen)
> +		return;
> +
> +	outval = cpu_to_le32(outval);
> +
> +	newbuf = (const unsigned char *)&outval;
> +	lpcdev = (struct hisilpc_dev *)devobj;
> +
> +	iopara.opflags = FG_INCRADDR_LPC;
> +	iopara.csize = dlen;
> +
> +	hisilpc_target_out(lpcdev, &iopara, ptaddr, newbuf, dlen);
> +}
> +
> +
> +/**
> + * hisilpc_comm_ins - read/input the data in buffer to the I/O peripheral
> + *		    through LPC, it corresponds to ins(b,w,l)
> + * @devobj: pointer to the device information relevant to LPC controller.
> + * @ptaddr: the target I/O port address.
> + * @inbuf: a buffer where read/input data bytes are stored.
> + * @dlen: the data length required writing to the target I/O port .
> + * @count: how many data units whose length is dlen will be read.
> + *
> + */
> +static u64 hisilpc_comm_ins(void *devobj, unsigned long ptaddr,
> +			void *inbuf, size_t dlen, unsigned int count)
> +{
> +	struct hisilpc_dev *lpcdev;
> +	struct lpc_cycle_para iopara;
> +	unsigned char *newbuf;
> +	unsigned int loopcnt, cntleft;
> +	unsigned int max_perburst;
> +	int ret = 0;
> +
> +	if (!devobj || !inbuf || !count || !dlen ||
> +			dlen > LPC_MAX_DULEN || (dlen & (dlen - 1)))
> +		return -1;
> +
> +	iopara.opflags = 0;
> +	if (dlen > 1)
> +		iopara.opflags |= FG_INCRADDR_LPC;
> +	iopara.csize = dlen;
> +
> +	lpcdev = (struct hisilpc_dev *)devobj;
> +	newbuf = (unsigned char *)inbuf;
> +	/*
> +	 * ensure data stream whose lenght is multiple of dlen to be processed
> +	 * each IO input
> +	 */
> +	max_perburst = LPC_MAX_OPCNT & (~(dlen - 1));
> +	cntleft = count * dlen;
> +	do {
> +		loopcnt = (cntleft >= max_perburst) ? max_perburst : cntleft;
> +		ret = hisilpc_target_in(lpcdev, &iopara, ptaddr, newbuf,
> +						loopcnt);
> +		if (ret)
> +			break;
> +		newbuf += loopcnt;
> +		cntleft -= loopcnt;
> +	} while (cntleft);
> +
> +	return ret;
> +}
> +
> +/**
> + * hisilpc_comm_outs - write/output the data in buffer to the I/O peripheral
> + *		    through LPC, it corresponds to outs(b,w,l)
> + * @devobj: pointer to the device information relevant to LPC controller.
> + * @ptaddr: the target I/O port address.
> + * @outbuf: a buffer where write/output data bytes are stored.
> + * @dlen: the data length required writing to the target I/O port .
> + * @count: how many data units whose length is dlen will be written.
> + *
> + */
> +static void hisilpc_comm_outs(void *devobj, unsigned long ptaddr,
> +			const void *outbuf, size_t dlen, unsigned int count)
> +{
> +	struct hisilpc_dev *lpcdev;
> +	struct lpc_cycle_para iopara;
> +	const unsigned char *newbuf;
> +	unsigned int loopcnt, cntleft;
> +	unsigned int max_perburst;
> +	int ret = 0;
> +
> +	if (!devobj || !outbuf || !count || !dlen ||
> +			dlen > LPC_MAX_DULEN || (dlen & (dlen - 1)))
> +		return;
> +
> +	iopara.opflags = 0;
> +	if (dlen > 1)
> +		iopara.opflags |= FG_INCRADDR_LPC;
> +	iopara.csize = dlen;
> +
> +	lpcdev = (struct hisilpc_dev *)devobj;
> +	newbuf = (unsigned char *)outbuf;
> +	/*
> +	 * ensure data stream whose lenght is multiple of dlen to be processed
> +	 * each IO input
> +	 */
> +	max_perburst = LPC_MAX_OPCNT & (~(dlen - 1));
> +	cntleft = count * dlen;
> +	do {
> +		loopcnt = (cntleft >= max_perburst) ? max_perburst : cntleft;
> +		ret = hisilpc_target_out(lpcdev, &iopara, ptaddr, newbuf,
> +						loopcnt);
> +		if (ret)
> +			break;
> +		newbuf += loopcnt;
> +		cntleft -= loopcnt;
> +	} while (cntleft);
> +}
> +
> +
> +/**
> + * hisilpc_probe - the probe callback function for hisi lpc device,
> + *		will finish all the intialization.
> + * @pdev: the platform device corresponding to hisi lpc
> + *
> + * Returns 0 on success, non-zero on fail.
> + *
> + */
> +static int hisilpc_probe(struct platform_device *pdev)
> +{
> +	struct resource *iores;
> +	struct hisilpc_dev *lpcdev;
> +	int ret;
> +
> +	dev_info(&pdev->dev, "hslpc start probing...\n");
> +
> +	lpcdev = devm_kzalloc(&pdev->dev,
> +				sizeof(struct hisilpc_dev), GFP_KERNEL);
> +	if (!lpcdev)
> +		return -ENOMEM;
> +
> +	spin_lock_init(&lpcdev->cycle_lock);
> +	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	lpcdev->membase = devm_ioremap_resource(&pdev->dev, iores);
> +	if (IS_ERR(lpcdev->membase)) {
> +		dev_err(&pdev->dev, "No mem resource for memory mapping!\n");
> +		return PTR_ERR(lpcdev->membase);
> +	}
> +	/*
> +	 * The first PCIBIOS_MIN_IO is reserved specific for indirectIO.
> +	 * It will separate indirectIO range from pci host bridge to
> +	 * avoid the possible PIO conflict.
> +	 * Set the indirectIO range directly here.
> +	 */
> +	lpcdev->io_ops.start = 0;
> +	lpcdev->io_ops.end = PCIBIOS_MIN_IO - 1;
> +	lpcdev->io_ops.devpara = lpcdev;
> +	lpcdev->io_ops.pfin = hisilpc_comm_in;
> +	lpcdev->io_ops.pfout = hisilpc_comm_out;
> +	lpcdev->io_ops.pfins = hisilpc_comm_ins;
> +	lpcdev->io_ops.pfouts = hisilpc_comm_outs;
> +
> +	platform_set_drvdata(pdev, lpcdev);
> +
> +	arm64_set_extops(&lpcdev->io_ops);
> +
> +	/*
> +	 * The children scanning is only for dts mode. For ACPI children,
> +	 * the corresponding devices had be created during acpi scanning.
> +	 */
> +	ret = 0;
> +	if (!has_acpi_companion(&pdev->dev))
> +		ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
> +
> +	if (!ret)
> +		dev_info(&pdev->dev, "hslpc end probing. range[0x%lx - %lx]\n",
> +			arm64_extio_ops->start, arm64_extio_ops->end);
> +	else
> +		dev_info(&pdev->dev, "hslpc probing is fail(%d)\n", ret);
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id hisilpc_of_match[] = {
> +	{
> +		.compatible = "hisilicon,low-pin-count",
> +	},
> +	{},
> +};
> +
> +static const struct acpi_device_id hisilpc_acpi_match[] = {
> +	{"HISI0191", },
> +	{},
> +};
> +
> +static struct platform_driver hisilpc_driver = {
> +	.driver = {
> +		.name           = "hisi_lpc",
> +		.of_match_table = hisilpc_of_match,
> +		.acpi_match_table = hisilpc_acpi_match,
> +	},
> +	.probe = hisilpc_probe,
> +};
> +
> +
> +builtin_platform_driver(hisilpc_driver);
> -- 
> 1.9.1
> 
> --
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