[bug report] ata: ahci: ceva: Update the driver to support xilinx GT phy

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Piyush Mehta,

The patch 9a9d3abe24bb: "ata: ahci: ceva: Update the driver to
support xilinx GT phy" from Feb 8, 2021, leads to the following
static checker warning:

	drivers/ata/ahci_ceva.c:213 ceva_ahci_probe()
	warn: pointer error 'PTR_ERR(cevapriv->rst)' not handled

drivers/ata/ahci_ceva.c
   192  static int ceva_ahci_probe(struct platform_device *pdev)
   193  {
   194          struct device_node *np = pdev->dev.of_node;
   195          struct device *dev = &pdev->dev;
   196          struct ahci_host_priv *hpriv;
   197          struct ceva_ahci_priv *cevapriv;
   198          enum dev_dma_attr attr;
   199          int rc;
   200  
   201          cevapriv = devm_kzalloc(dev, sizeof(*cevapriv), GFP_KERNEL);
   202          if (!cevapriv)
   203                  return -ENOMEM;
   204  
   205          cevapriv->ahci_pdev = pdev;
   206  
   207          cevapriv->rst = devm_reset_control_get_optional_exclusive(&pdev->dev,
   208                                                                    NULL);
   209          if (IS_ERR(cevapriv->rst))
   210                  dev_err_probe(&pdev->dev, PTR_ERR(cevapriv->rst),
   211                                "failed to get reset\n");


The function just continues if "cevapriv->rst" is an error pointer.  We
should probably return an error, because the user asked us to do
something and we failed.  Another option is to set it to NULL.

   212  
   213          hpriv = ahci_platform_get_resources(pdev, 0);
   214          if (IS_ERR(hpriv))
   215                  return PTR_ERR(hpriv);
   216  
   217          if (!cevapriv->rst) {

It's an error pointer so it's not NULL

   218                  rc = ahci_platform_enable_resources(hpriv);
   219                  if (rc)
   220                          return rc;
   221          } else {
   222                  int i;
   223  
   224                  rc = ahci_platform_enable_clks(hpriv);
   225                  if (rc)
   226                          return rc;
   227                  /* Assert the controller reset */
   228                  reset_control_assert(cevapriv->rst);
                                             ^^^^^^^^^^^^^
This will trigger a WARN_ON().

   229  
   230                  for (i = 0; i < hpriv->nports; i++) {
   231                          rc = phy_init(hpriv->phys[i]);

regards,
dan carpenter