Re: [PATCH mfd+gpio 1/2] drivers: mfd: Add support for Moxtet bus

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

Hi Marek,

Thank you for the patch! Perhaps something to improve:

url:    https://github.com/0day-ci/linux/commits/Marek-Beh-n/drivers-mfd-Add-support-for-Moxtet-bus/20180831-031806
base:   https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git for-mfd-next

smatch warnings:
drivers/mfd/moxtet.c:267 of_register_moxtet_device() warn: passing zero to 'ERR_PTR'

# https://github.com/0day-ci/linux/commit/316bda5c94917aa3b0a67c3cf79cca211d08138d
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 316bda5c94917aa3b0a67c3cf79cca211d08138d
vim +/ERR_PTR +267 drivers/mfd/moxtet.c

316bda5c Marek Behún 2018-08-30  213  
316bda5c Marek Behún 2018-08-30  214  static struct moxtet_device *
316bda5c Marek Behún 2018-08-30  215  of_register_moxtet_device(struct moxtet *moxtet, struct device_node *nc)
316bda5c Marek Behún 2018-08-30  216  {
316bda5c Marek Behún 2018-08-30  217  	struct moxtet_device *dev;
316bda5c Marek Behún 2018-08-30  218  	u32 val;
316bda5c Marek Behún 2018-08-30  219  	int ret;
316bda5c Marek Behún 2018-08-30  220  
316bda5c Marek Behún 2018-08-30  221  	dev = moxtet_alloc_device(moxtet);
316bda5c Marek Behún 2018-08-30  222  	if (!dev) {
316bda5c Marek Behún 2018-08-30  223  		dev_err(moxtet->dev,
316bda5c Marek Behún 2018-08-30  224  			"Moxtet device alloc error for %pOF\n", nc);
316bda5c Marek Behún 2018-08-30  225  		return ERR_PTR(-ENOMEM);
316bda5c Marek Behún 2018-08-30  226  	}
316bda5c Marek Behún 2018-08-30  227  
316bda5c Marek Behún 2018-08-30  228  	ret = of_property_read_u32(nc, "reg", &val);
316bda5c Marek Behún 2018-08-30  229  	if (ret || val >= TURRIS_MOX_MAX_MODULES) {
                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
No error code set.  It means we return NULL.  Presumably it leads to a
NULL dereference in the caller?

316bda5c Marek Behún 2018-08-30  230  		dev_err(moxtet->dev, "%pOF has no valid 'reg' property (%d)\n",
316bda5c Marek Behún 2018-08-30  231  			nc, ret);
316bda5c Marek Behún 2018-08-30  232  		goto err_put;
316bda5c Marek Behún 2018-08-30  233  	}
316bda5c Marek Behún 2018-08-30  234  	dev->idx = val;
316bda5c Marek Behún 2018-08-30  235  
316bda5c Marek Behún 2018-08-30  236  	ret = of_property_read_u32(nc, "moxtet,id", &val);
316bda5c Marek Behún 2018-08-30  237  	if (ret || val > 0xf) {
                                                   ^^^^^^^^^

316bda5c Marek Behún 2018-08-30  238  		dev_err(moxtet->dev,
316bda5c Marek Behún 2018-08-30  239  			"%pOF has no valid 'moxtet,id' property (%d)\n", nc,
316bda5c Marek Behún 2018-08-30  240  			ret);
316bda5c Marek Behún 2018-08-30  241  		goto err_put;
316bda5c Marek Behún 2018-08-30  242  	}
316bda5c Marek Behún 2018-08-30  243  	dev->id = val;
316bda5c Marek Behún 2018-08-30  244  
316bda5c Marek Behún 2018-08-30  245  	if (moxtet->modules[dev->idx] != dev->id) {
316bda5c Marek Behún 2018-08-30  246  		dev_err(moxtet->dev,
316bda5c Marek Behún 2018-08-30  247  			"%pOF requested Moxtet device ID 0x%x, 0x%x found\n",
316bda5c Marek Behún 2018-08-30  248  			nc, dev->id, moxtet->modules[dev->idx]);
316bda5c Marek Behún 2018-08-30  249  		goto err_put;
                                                ^^^^^^^^^^^^

316bda5c Marek Behún 2018-08-30  250  	}
316bda5c Marek Behún 2018-08-30  251  
316bda5c Marek Behún 2018-08-30  252  	of_node_get(nc);
316bda5c Marek Behún 2018-08-30  253  	dev->dev.of_node = nc;
316bda5c Marek Behún 2018-08-30  254  
316bda5c Marek Behún 2018-08-30  255  	ret = moxtet_add_device(dev);
316bda5c Marek Behún 2018-08-30  256  	if (ret) {
316bda5c Marek Behún 2018-08-30  257  		dev_err(moxtet->dev,
316bda5c Marek Behún 2018-08-30  258  			"Moxtet device register error for %pOF\n", nc);
316bda5c Marek Behún 2018-08-30  259  		of_node_put(nc);
316bda5c Marek Behún 2018-08-30  260  		goto err_put;
316bda5c Marek Behún 2018-08-30  261  	}
316bda5c Marek Behún 2018-08-30  262  
316bda5c Marek Behún 2018-08-30  263  	return dev;
316bda5c Marek Behún 2018-08-30  264  
316bda5c Marek Behún 2018-08-30  265  err_put:
316bda5c Marek Behún 2018-08-30  266  	put_device(&dev->dev);
316bda5c Marek Behún 2018-08-30 @267  	return ERR_PTR(ret);
316bda5c Marek Behún 2018-08-30  268  }
316bda5c Marek Behún 2018-08-30  269  

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