Re: [PATCH v5 3/3] I2C: mediatek: Add driver for MediaTek MT8173 I2C controller

From: Sascha Hauer <s.hauer@pengutronix.de>
To: Eddie Huang <eddie.huang@mediatek.com>
Cc: "Wolfram Sang" <wsa@the-dreams.de>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Mark Rutland" <mark.rutland@arm.com>,
	linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
	"David Box" <david.e.box@linux.intel.com>,
	"Lee Jones" <lee.jones@linaro.org>,
	"Jean Delvare" <jdelvare@suse.de>,
	"Xudong Chen" <xudong.chen@mediatek.com>,
	"Boris BREZILLON" <boris.brezillon@free-electrons.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Liguo Zhang" <liguo.zhang@mediatek.com>,
	"Wei Yan" <sledge.yanwei@huawei.com>,
	"Bjorn Andersson" <bjorn.andersson@sonymobile.com>,
	"Neelesh Gupta" <neelegup@linux.vnet.ibm.com>,
	devicetree@vger.kernel.org, "Pawel Moll" <pawel.moll@arm.com>,
	"Ian Campbell" <ijc+devicetree@hellion.org.uk>,
	"Beniamino Galvani" <b.galvani@gmail.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	srv_heupstream@mediatek.com,
	"Anders Berg" <anders.berg@avagotech.com>,
	"Jim Cromie" <jim.cromie@gmail.com>,
	"Simon Glass" <sjg@chromium.org>,
	"Max Schwarz" <max.schwarz@online.de>,
	"Doug Anderson" <dianders@chromium.org>,
	"Sascha Hauer" <kernel@pengutronix.de>,
	"Kumar Gala" <galak@codeaurora.org>
Subject: Re: [PATCH v5 3/3] I2C: mediatek: Add driver for MediaTek MT8173 I2C controller
Date: Mon, 23 Mar 2015 08:39:05 +0100	[thread overview]
Message-ID: <20150323073905.GF9742@pengutronix.de> (raw)
In-Reply-To: <1426917922-61356-4-git-send-email-eddie.huang@mediatek.com>

On Sat, Mar 21, 2015 at 02:05:22PM +0800, Eddie Huang wrote:
> Add mediatek MT8173 I2C controller driver. Compare to I2C controller
> of earlier mediatek SoC, MT8173 fix write-then-read limitation, and
> also increase message size to 64kb.
> 

[...]

> +static const struct i2c_adapter_quirks mt8173_i2c_quirks = {
> +	.max_num_msgs = MAX_MSG_NUM_MT8173,
> +	.max_write_len = MAX_DMA_TRANS_SIZE_MT8173,
> +	.max_read_len = MAX_DMA_TRANS_SIZE_MT8173,
> +	.max_comb_1st_msg_len = MAX_DMA_TRANS_SIZE_MT8173,
> +	.max_comb_2nd_msg_len = MAX_WRRD_TRANS_SIZE_MT8173,
> +};
> +
>  static int mtk_i2c_probe(struct platform_device *pdev)
>  {
>  	int ret = 0;
> @@ -587,7 +626,8 @@ static int mtk_i2c_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  
>  	i2c->platform_compat = mtk_get_device_prop(pdev);
> -	if (i2c->have_pmic && (i2c->platform_compat & COMPAT_MT6577))
> +	if (i2c->have_pmic && (i2c->platform_compat &
> +			(COMPAT_MT6577 | COMPAT_MT8173)))
>  		return -EINVAL;
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> @@ -613,7 +653,10 @@ static int mtk_i2c_probe(struct platform_device *pdev)
>  	i2c->adap.dev.parent = &pdev->dev;
>  	i2c->adap.owner = THIS_MODULE;
>  	i2c->adap.algo = &mtk_i2c_algorithm;
> -	i2c->adap.quirks = &mt6577_i2c_quirks;
> +	if (i2c->platform_compat & COMPAT_MT8173)
> +		i2c->adap.quirks = &mt8173_i2c_quirks;
> +	else
> +		i2c->adap.quirks = &mt6577_i2c_quirks;

Instead of putting an integer into struct of_device_id you should
introduce a

struct mtk_i2c_data {
	struct i2c_adapter_quirks quirks;
	int compat;
	/* Additional SoC specific data */
};

and put a pointer to this directly into the of_device_id. This way you
need less casting and can put newly discovered differences diretly into
some data struct and don't have to introduce if(socxy) ... else ...
everytime.

Sascha

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