linux-kernel - Re: [PATCH 3/6 v2] mfd: stmpe: prope properly from the device tree

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Date:	Wed, 23 Apr 2014 14:27:47 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Linus Walleij <linus.walleij@...aro.org>
Cc:	Samuel Ortiz <sameo@...ux.intel.com>, linux-kernel@...r.kernel.org,
	Silvio F <silvio.fricke@...il.com>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Shawn Guo <shawn.guo@...aro.org>,
	Viresh Kumar <viresh.linux@...il.com>,
	Shiraz Hashim <shiraz.hashim@...com>, spear-devel@...t.st.com
Subject: Re: [PATCH 3/6 v2] mfd: stmpe: prope properly from the device tree

Can you fix the $SUBJECT line please?

> The current STMPE I2C probing code does not really match the
> compatible strings - it matches node names happening to give
> the right device name. Instead, let's introduce some real
> compatible matching, more complex, more accurate. Make the
> driver depend on OF since all platforms using it are DT-only.
> 
> Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
> ---
> ChangeLog v1->v2:
> - Make driver depend on OF and remove some ifdeffery that way.
> - Squash OF match table to single lines.
> - Merge of-specific probe function into probe().
> - Print a small nag if DT is using the node name trick to make
>   the driver probe.
> ---
>  drivers/mfd/Kconfig     |  1 +
>  drivers/mfd/stmpe-i2c.c | 31 ++++++++++++++++++++++++++++++-
>  2 files changed, 31 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 33834120d057..29be025d5835 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -675,6 +675,7 @@ config MFD_DB8500_PRCMU
>  config MFD_STMPE
>  	bool "STMicroelectronics STMPE"
>  	depends on (I2C=y || SPI_MASTER=y)
> +	depends on OF
>  	select MFD_CORE
>  	help
>  	  Support for the STMPE family of I/O Expanders from
> diff --git a/drivers/mfd/stmpe-i2c.c b/drivers/mfd/stmpe-i2c.c
> index 0da02e11d58e..da15dda04df9 100644
> --- a/drivers/mfd/stmpe-i2c.c
> +++ b/drivers/mfd/stmpe-i2c.c
> @@ -14,6 +14,7 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/types.h>
> +#include <linux/of_device.h>
>  #include "stmpe.h"
>  
>  static int i2c_reg_read(struct stmpe *stmpe, u8 reg)
> @@ -52,15 +53,42 @@ static struct stmpe_client_info i2c_ci = {
>  	.write_block = i2c_block_write,
>  };
>  
> +static const struct of_device_id stmpe_of_match[] = {
> +	{ .compatible = "st,stmpe610", .data = (void *)STMPE610, },
> +	{ .compatible = "st,stmpe801", .data = (void *)STMPE801, },
> +	{ .compatible = "st,stmpe811", .data = (void *)STMPE811, },
> +	{ .compatible = "st,stmpe1601", .data = (void *)STMPE1601, },
> +	{ .compatible = "st,stmpe1801", .data = (void *)STMPE1801, },
> +	{ .compatible = "st,stmpe2401", .data = (void *)STMPE2401, },
> +	{ .compatible = "st,stmpe2403", .data = (void *)STMPE2403, },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, stmpe_of_match);
> +
>  static int
>  stmpe_i2c_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
>  {
> +	int partnum;
> +	const struct of_device_id *of_id;
> +
>  	i2c_ci.data = (void *)id;
>  	i2c_ci.irq = i2c->irq;
>  	i2c_ci.client = i2c;
>  	i2c_ci.dev = &i2c->dev;
>  
> -	return stmpe_probe(&i2c_ci, id->driver_data);
> +	of_id = of_match_device(stmpe_of_match, &i2c->dev);
> +	if (!of_id) {
> +		/*
> +		 * This happens when the I2C ID matches the node name
> +		 * but no real compatible string has been given.
> +		 */
> +		dev_info(&i2c->dev, "matching on node name, compatible is preferred\n");
> +		partnum = id->driver_data;
> +		return -ENODEV;

This changes the semantics since v1.

I don't think you want to return error at all.

> +	} else
> +		partnum = (int)of_id->data;
> +
> +	return stmpe_probe(&i2c_ci, partnum);
>  }
>  
>  static int stmpe_i2c_remove(struct i2c_client *i2c)
> @@ -89,6 +117,7 @@ static struct i2c_driver stmpe_i2c_driver = {
>  #ifdef CONFIG_PM
>  		.pm = &stmpe_dev_pm_ops,
>  #endif
> +		.of_match_table = stmpe_of_match,
>  	},
>  	.probe		= stmpe_i2c_probe,
>  	.remove		= stmpe_i2c_remove,

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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