drm: dw_hdmi: use of_get_i2c_adapter_by_node interface

This change is needed to properly lock I2C bus driver, which serves
DDC.

The change fixes an overflow over zero of I2C bus driver user counter:

  root@imx6q:~# lsmod
  Not tainted
  dw_hdmi_ahb_audio 4082 0 - Live 0xbf02c000
  dw_hdmi_imx 3498 0 - Live 0xbf00d000
  dw_hdmi 16398 2 dw_hdmi_ahb_audio,dw_hdmi_imx, Live 0xbf004000
  i2c_imx 16687 0 - Live 0xbf017000

  root@imx6q:~# rmmod dw_hdmi_imx
  root@imx6q:~# lsmod
  Not tainted
  dw_hdmi_ahb_audio 4082 0 - Live 0xbf02c000
  dw_hdmi 16398 1 dw_hdmi_ahb_audio, Live 0xbf004000
  i2c_imx 16687 -1 - Live 0xbf017000
                ^^

  root@imx6q:~# rmmod i2c_imx
  rmmod: ERROR: Module i2c_imx is in use

Note that prior to this change put_device() coupled with
of_find_i2c_adapter_by_node() was missing on error path of
dw_hdmi_bind(), added i2c_put_adapter() there along with the change.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
index 77ab473..ce3527c 100644 (file)
--- a/drivers/gpu/drm/bridge/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/dw-hdmi.c
@@ -1686,7 +1686,7 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
 
        ddc_node = of_parse_phandle(np, "ddc-i2c-bus", 0);
        if (ddc_node) {
-               hdmi->ddc = of_find_i2c_adapter_by_node(ddc_node);
+               hdmi->ddc = of_get_i2c_adapter_by_node(ddc_node);
                of_node_put(ddc_node);
                if (!hdmi->ddc) {
                        dev_dbg(hdmi->dev, "failed to read ddc node\n");
@@ -1698,20 +1698,22 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
        }
 
        hdmi->regs = devm_ioremap_resource(dev, iores);
-       if (IS_ERR(hdmi->regs))
-               return PTR_ERR(hdmi->regs);
+       if (IS_ERR(hdmi->regs)) {
+               ret = PTR_ERR(hdmi->regs);
+               goto err_res;
+       }
 
        hdmi->isfr_clk = devm_clk_get(hdmi->dev, "isfr");
        if (IS_ERR(hdmi->isfr_clk)) {
                ret = PTR_ERR(hdmi->isfr_clk);
                dev_err(hdmi->dev, "Unable to get HDMI isfr clk: %d\n", ret);
-               return ret;
+               goto err_res;
        }
 
        ret = clk_prepare_enable(hdmi->isfr_clk);
        if (ret) {
                dev_err(hdmi->dev, "Cannot enable HDMI isfr clock: %d\n", ret);
-               return ret;
+               goto err_res;
        }
 
        hdmi->iahb_clk = devm_clk_get(hdmi->dev, "iahb");
@@ -1797,6 +1799,8 @@ err_iahb:
        clk_disable_unprepare(hdmi->iahb_clk);
 err_isfr:
        clk_disable_unprepare(hdmi->isfr_clk);
+err_res:
+       i2c_put_adapter(hdmi->ddc);
 
        return ret;
 }