[PATCH v2 1/3] drm: dw_hdmi: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

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 at mx6q:~# lsmod | grep i2c
    i2c_imx                15348  0
    root at mx6q:~# lsmod | grep dw_hdmi_imx
    dw_hdmi_imx             3567  0
    dw_hdmi                15850  1 dw_hdmi_imx
    imxdrm                  8610  3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
    root at mx6q:~# rmmod dw_hdmi_imx
    root at mx6q:~# lsmod | grep i2c
    i2c_imx                15348  -1

                                 ^^^^^

    root at mx6q:~# 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 at mentor.com>
Cc: Russell King <rmk+kernel at arm.linux.org.uk>
Cc: Philipp Zabel <p.zabel at pengutronix.de>
Cc: Andy Yan <andy.yan at rock-chips.com>
---
Changes from v1 to v2:
- none

 drivers/gpu/drm/bridge/dw_hdmi.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index 0083d4e..c2d804f 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -1638,7 +1638,7 @@ 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");
@@ -1650,20 +1650,22 @@ 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");
@@ -1729,6 +1731,8 @@ 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;
 }
-- 
2.5.0