From: "zhichang.yuan" <yuanzhichang@hisilicon.com>
To: Arnd Bergmann <arnd@arndb.de>, <linux-arm-kernel@lists.infradead.org>
Cc: <linuxarm@huawei.com>, <linux-kernel@vger.kernel.org>,
<lorenzo.pieralisi@arm.com>, <minyard@acm.org>,
<benh@kernel.crashing.org>, <gabriele.paoloni@huawei.com>,
<john.garry@huawei.com>, <liviu.dudau@arm.com>,
<zhichang.yuan02@gmail.com>, <zourongrong@gmail.com>
Subject: Re: [PATCH V2 2/4] ARM64 LPC: LPC driver implementation on Hip06
Date: Thu, 8 Sep 2016 16:06:01 +0800 [thread overview]
Message-ID: <57D11BE9.7010709@hisilicon.com> (raw)
In-Reply-To: <2175767.JxAh0qjf0L@wuerfel>
Hi, Arnd
On 2016/9/7 23:27, Arnd Bergmann wrote:
> On Wednesday, September 7, 2016 9:33:51 PM CEST Zhichang Yuan wrote:
>
>> +
>> +struct hisilpc_dev;
>> +
>> +/* This flag is specific to differentiate earlycon operations and the others */
>> +#define FG_EARLYCON_LPC (0x01U << 0)
>> +/*
>> + * 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 (0x01U << 1)
>
> Better express the constants as
>
> #define FG_EARLYCON_LPC 0x0001
> #define FG_INCRADDR_LPC 0x0002
Ok. Will revise.
>
>> +struct lpc_io_ops {
>> + unsigned int periosz;
>> + int (*lpc_iord)(struct hisilpc_dev *pdev, struct lpc_cycle_para *para,
>> + unsigned long ptaddr, unsigned char *buf,
>> + unsigned long dlen);
>> + int (*lpc_iowr)(struct hisilpc_dev *pdev, struct lpc_cycle_para *para,
>> + unsigned long ptaddr,
>> + const unsigned char *buf,
>> + unsigned long dlen);
>> +};
>
> The operations are not needed unless we also put the earlycon support
> in, so maybe leave them out from the first patch and only add them
> later (or drop the earlycon support if possible).
Do you want to remove the struct lpc_io_ops member from struct hisilpc_dev??
I think we can not do that.
These two functions are essential rd/wr operation for Hip06 LPC. They will be fallen into
when the upper layer drivers call their own IO in/out functions, such as serial_in/serial_out
for 8250 serial.
I can define lpc_iord/lpc_iowr directly in struct hisilpc_dev and cancel the definition of
struct lpc_io_ops. In my original idea, several LPC cycle types will be supported. Each cycle
type has its specific ops. Now, only one cycle type is needed, the struct lpc_io_ops is not
meaningful.
>
>> +/**
>> + * hisilpc_remove - the remove callback function for hisi lpc device.
>> + * @pdev: the platform device corresponding to hisi lpc that is to be removed.
>> + *
>> + * Returns 0 on success, non-zero on fail.
>> + *
>> + */
>> +static int hisilpc_remove(struct platform_device *pdev)
>> +{
>> + return 0;
>> +}
>
> It seems that it should not be possible to remove this driver,
> please use builtin_platform_driver() then and remove this callback.
Yes. Will use builtin_platform_driver for the unnecessary remove callback.
Best,
Zhichang
>
> Arnd
>
> .
>
next prev parent reply other threads:[~2016-09-08 8:08 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-07 13:33 [PATCH V2 0/4] ARM64 LPC: legacy ISA I/O support Zhichang Yuan
2016-09-07 13:33 ` [PATCH V2 1/4] ARM64 LPC: Indirect ISA port IO introduced Zhichang Yuan
2016-09-07 15:06 ` Arnd Bergmann
2016-09-08 7:45 ` zhichang.yuan
2016-09-08 13:23 ` Arnd Bergmann
2016-09-13 6:08 ` zhichang
2016-09-07 15:21 ` kbuild test robot
2016-09-07 13:33 ` [PATCH V2 2/4] ARM64 LPC: LPC driver implementation on Hip06 Zhichang Yuan
2016-09-07 15:27 ` Arnd Bergmann
2016-09-08 8:06 ` zhichang.yuan [this message]
2016-09-08 10:00 ` Arnd Bergmann
2016-09-13 6:31 ` zhichang
2016-09-14 12:34 ` Arnd Bergmann
2016-09-07 17:51 ` kbuild test robot
2016-09-07 13:33 ` [PATCH V2 3/4] ARM64 LPC: support serial based on low-pin-count Zhichang Yuan
2016-09-07 14:50 ` Arnd Bergmann
2016-09-08 9:51 ` zhichang
2016-09-08 9:58 ` Arnd Bergmann
2016-09-14 11:48 ` zhichang.yuan
2016-09-14 12:07 ` Arnd Bergmann
2016-09-07 13:33 ` [PATCH V2 4/4] ARM64 LPC: support earlycon for UART connected to LPC Zhichang Yuan
2016-09-07 14:52 ` Arnd Bergmann
2016-09-08 10:04 ` zhichang
2016-09-08 11:04 ` Arnd Bergmann
2016-09-14 11:26 ` zhichang
2016-09-14 12:36 ` Arnd Bergmann
2016-09-08 9:26 ` kbuild test robot
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