On 14.05.2020 13:30, Vincent Whitchurch wrote:
If adv7511's devm_clk_get() for the cec clock returns -EPROBE_DEFER, we end up in an infinite probe loop. This happens:
(1) adv7511's probe is called.
(2) adv7511's probe adds some secondary i2c devices which bind to the dummy driver and thus call driver_deferred_probe_trigger() and increment deferred_trigger_count (see driver_bound()).
(3) adv7511's probe returns -EPROBE_DEFER, and since the deferred_trigger_count has changed during the probe call, driver_deferred_probe_trigger() is called immediately (see really_probe()) and adv7511's probe is scheduled.
(4) Goto step 1.
[ 61.972915] really_probe: bus: 'i2c': really_probe: probing driver adv7511 with device 0-0039 [ 61.992734] really_probe: bus: 'i2c': really_probe: probing driver dummy with device 0-003f [ 61.993343] driver_bound: driver: 'dummy': driver_bound: bound to device '0-003f' [ 61.993626] really_probe: bus: 'i2c': really_probe: bound device 0-003f to driver dummy [ 61.995604] really_probe: bus: 'i2c': really_probe: probing driver dummy with device 0-0038 [ 61.996381] driver_bound: driver: 'dummy': driver_bound: bound to device '0-0038' [ 61.996663] really_probe: bus: 'i2c': really_probe: bound device 0-0038 to driver dummy [ 61.998651] really_probe: bus: 'i2c': really_probe: probing driver dummy with device 0-003c [ 61.999222] driver_bound: driver: 'dummy': driver_bound: bound to device '0-003c' [ 61.999496] really_probe: bus: 'i2c': really_probe: bound device 0-003c to driver dummy [ 62.010050] really_probe: i2c 0-0039: Driver adv7511 requests probe deferral [ 62.011380] really_probe: bus: 'platform': really_probe: probing driver pwm-clock with device clock-cec [ 62.012812] really_probe: platform clock-cec: Driver pwm-clock requests probe deferral [ 62.024679] really_probe: bus: 'i2c': really_probe: probing driver adv7511 with device 0-0039
Fix this by calling devm_clk_get() before registering the secondary devices.
Signed-off-by: Vincent Whitchurch vincent.whitchurch@axis.com
v3: Make adv7511_cec_init() return void. v2: Add devm_clk_put() in error path.
drivers/gpu/drm/bridge/adv7511/adv7511.h | 5 ++- drivers/gpu/drm/bridge/adv7511/adv7511_cec.c | 34 ++++++++------------ drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 15 ++++++--- 3 files changed, 25 insertions(+), 29 deletions(-)
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h b/drivers/gpu/drm/bridge/adv7511/adv7511.h index a9bb734366ae..05a66149b186 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511.h +++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h @@ -380,17 +380,16 @@ struct adv7511 { };
#ifdef CONFIG_DRM_I2C_ADV7511_CEC -int adv7511_cec_init(struct device *dev, struct adv7511 *adv7511); +void adv7511_cec_init(struct device *dev, struct adv7511 *adv7511); void adv7511_cec_irq_process(struct adv7511 *adv7511, unsigned int irq1); #else -static inline int adv7511_cec_init(struct device *dev, struct adv7511 *adv7511) +static inline void adv7511_cec_init(struct device *dev, struct adv7511 *adv7511) { unsigned int offset = adv7511->type == ADV7533 ? ADV7533_REG_CEC_OFFSET : 0;
regmap_write(adv7511->regmap, ADV7511_REG_CEC_CTRL + offset, ADV7511_CEC_CTRL_POWER_DOWN);
- return 0; } #endif
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_cec.c b/drivers/gpu/drm/bridge/adv7511/adv7511_cec.c index a20a45c0b353..ee0ed4fb67c1 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511_cec.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_cec.c @@ -286,28 +286,17 @@ static const struct cec_adap_ops adv7511_cec_adap_ops = { .adap_transmit = adv7511_cec_adap_transmit, };
-static int adv7511_cec_parse_dt(struct device *dev, struct adv7511 *adv7511) -{
- adv7511->cec_clk = devm_clk_get(dev, "cec");
- if (IS_ERR(adv7511->cec_clk)) {
int ret = PTR_ERR(adv7511->cec_clk);adv7511->cec_clk = NULL;return ret;- }
- clk_prepare_enable(adv7511->cec_clk);
- adv7511->cec_clk_freq = clk_get_rate(adv7511->cec_clk);
- return 0;
-}
-int adv7511_cec_init(struct device *dev, struct adv7511 *adv7511) +void adv7511_cec_init(struct device *dev, struct adv7511 *adv7511) { unsigned int offset = adv7511->type == ADV7533 ? ADV7533_REG_CEC_OFFSET : 0;
- int ret = adv7511_cec_parse_dt(dev, adv7511);
- int ret;
- if (ret)
goto err_cec_parse_dt;
if (!adv7511->cec_clk)
goto err_cec_no_clock;clk_prepare_enable(adv7511->cec_clk);
adv7511->cec_clk_freq = clk_get_rate(adv7511->cec_clk);
adv7511->cec_adap = cec_allocate_adapter(&adv7511_cec_adap_ops, adv7511, dev_name(dev), CEC_CAP_DEFAULTS, ADV7511_MAX_ADDRS);
@@ -334,7 +323,7 @@ int adv7511_cec_init(struct device *dev, struct adv7511 *adv7511) ret = cec_register_adapter(adv7511->cec_adap, dev); if (ret) goto err_cec_register;
- return 0;
return;
err_cec_register: cec_delete_adapter(adv7511->cec_adap);
@@ -342,8 +331,11 @@ int adv7511_cec_init(struct device *dev, struct adv7511 *adv7511) err_cec_alloc: dev_info(dev, "Initializing CEC failed with error %d, disabling CEC\n", ret); -err_cec_parse_dt:
- clk_disable_unprepare(adv7511->cec_clk);
- devm_clk_put(dev, adv7511->cec_clk);
- /* Ensure that adv7511_remove() doesn't attempt to disable it again. */
- adv7511->cec_clk = NULL;
Are you sure these three lines above are necessary? devm mechanism should free the clock and with failed probe remove should not be called.
Beside this:
Reviewed-by: Andrzej Hajda a.hajda@samsung.com
Regards
Andrzej
+err_cec_no_clock: regmap_write(adv7511->regmap, ADV7511_REG_CEC_CTRL + offset, ADV7511_CEC_CTRL_POWER_DOWN);
- return ret == -EPROBE_DEFER ? ret : 0; }
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 87b58c1acff4..8d8df6116082 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c @@ -1128,6 +1128,15 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id) if (ret) return ret;
- adv7511->cec_clk = devm_clk_get(dev, "cec");
- if (IS_ERR(adv7511->cec_clk)) {
ret = PTR_ERR(adv7511->cec_clk);if (ret == -EPROBE_DEFER)return ret;adv7511->cec_clk = NULL;- }
- ret = adv7511_init_regulators(adv7511); if (ret) { dev_err(dev, "failed to init regulators\n");
@@ -1218,9 +1227,7 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id) if (adv7511->type == ADV7511) adv7511_set_link_config(adv7511, &link_config);
- ret = adv7511_cec_init(dev, adv7511);
- if (ret)
goto err_unregister_cec;
adv7511_cec_init(dev, adv7511);
adv7511->bridge.funcs = &adv7511_bridge_funcs; adv7511->bridge.of_node = dev->of_node;
@@ -1232,8 +1239,6 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
err_unregister_cec: i2c_unregister_device(adv7511->i2c_cec);
- if (adv7511->cec_clk)
clk_disable_unprepare(adv7511->cec_clk);