>From: Ivan Vecera <[email protected]> >Sent: Tuesday, February 3, 2026 6:40 PM > >Allow drivers to register DPLL pins without manually specifying a pin >index. > >Currently, drivers must provide a unique pin index when calling >dpll_pin_get(). This works well for hardware-mapped pins but creates >friction for drivers handling virtual pins or those without a strict >hardware indexing scheme. > >Introduce DPLL_PIN_IDX_UNSPEC (U32_MAX). When a driver passes this >value as the pin index: >1. The core allocates a unique index using an IDA >2. The allocated index is mapped to a range starting above `INT_MAX` > >This separation ensures that dynamically allocated indices never collide >with standard driver-provided hardware indices, which are assumed to be >within the `0` to `INT_MAX` range. The index is automatically freed when >the pin is released in dpll_pin_put(). > >Reviewed-by: Aleksandr Loktionov <[email protected]>
LGTM, Reviewed-by: Arkadiusz Kubalewski <[email protected]> >Signed-off-by: Ivan Vecera <[email protected]> >--- >v2: >* fixed integer overflow in dpll_pin_idx_free() >--- > drivers/dpll/dpll_core.c | 48 ++++++++++++++++++++++++++++++++++++++-- > include/linux/dpll.h | 2 ++ > 2 files changed, 48 insertions(+), 2 deletions(-) > >diff --git a/drivers/dpll/dpll_core.c b/drivers/dpll/dpll_core.c >index b05fe2ba46d91..59081cf2c73ae 100644 >--- a/drivers/dpll/dpll_core.c >+++ b/drivers/dpll/dpll_core.c >@@ -10,6 +10,7 @@ > > #include <linux/device.h> > #include <linux/err.h> >+#include <linux/idr.h> > #include <linux/property.h> > #include <linux/slab.h> > #include <linux/string.h> >@@ -24,6 +25,7 @@ DEFINE_XARRAY_FLAGS(dpll_device_xa, XA_FLAGS_ALLOC); > DEFINE_XARRAY_FLAGS(dpll_pin_xa, XA_FLAGS_ALLOC); > > static RAW_NOTIFIER_HEAD(dpll_notifier_chain); >+static DEFINE_IDA(dpll_pin_idx_ida); > > static u32 dpll_device_xa_id; > static u32 dpll_pin_xa_id; >@@ -464,6 +466,36 @@ void dpll_device_unregister(struct dpll_device *dpll, > } > EXPORT_SYMBOL_GPL(dpll_device_unregister); > >+static int dpll_pin_idx_alloc(u32 *pin_idx) >+{ >+ int ret; >+ >+ if (!pin_idx) >+ return -EINVAL; >+ >+ /* Alloc unique number from IDA. Number belongs to <0, INT_MAX> >range */ >+ ret = ida_alloc(&dpll_pin_idx_ida, GFP_KERNEL); >+ if (ret < 0) >+ return ret; >+ >+ /* Map the value to dynamic pin index range <INT_MAX+1, U32_MAX> */ >+ *pin_idx = (u32)ret + INT_MAX + 1; >+ >+ return 0; >+} >+ >+static void dpll_pin_idx_free(u32 pin_idx) >+{ >+ if (pin_idx <= INT_MAX) >+ return; /* Not a dynamic pin index */ >+ >+ /* Map the index value from dynamic pin index range to IDA range and >+ * free it. >+ */ >+ pin_idx -= (u32)INT_MAX + 1; >+ ida_free(&dpll_pin_idx_ida, pin_idx); >+} >+ > static void dpll_pin_prop_free(struct dpll_pin_properties *prop) > { > kfree(prop->package_label); >@@ -521,9 +553,18 @@ dpll_pin_alloc(u64 clock_id, u32 pin_idx, struct >module *module, > struct dpll_pin *pin; > int ret; > >+ if (pin_idx == DPLL_PIN_IDX_UNSPEC) { >+ ret = dpll_pin_idx_alloc(&pin_idx); >+ if (ret) >+ return ERR_PTR(ret); >+ } else if (pin_idx > INT_MAX) { >+ return ERR_PTR(-EINVAL); >+ } > pin = kzalloc(sizeof(*pin), GFP_KERNEL); >- if (!pin) >- return ERR_PTR(-ENOMEM); >+ if (!pin) { >+ ret = -ENOMEM; >+ goto err_pin_alloc; >+ } > pin->pin_idx = pin_idx; > pin->clock_id = clock_id; > pin->module = module; >@@ -551,6 +592,8 @@ dpll_pin_alloc(u64 clock_id, u32 pin_idx, struct >module *module, > dpll_pin_prop_free(&pin->prop); > err_pin_prop: > kfree(pin); >+err_pin_alloc: >+ dpll_pin_idx_free(pin_idx); > return ERR_PTR(ret); > } > >@@ -654,6 +697,7 @@ void dpll_pin_put(struct dpll_pin *pin) > xa_destroy(&pin->ref_sync_pins); > dpll_pin_prop_free(&pin->prop); > fwnode_handle_put(pin->fwnode); >+ dpll_pin_idx_free(pin->pin_idx); > kfree_rcu(pin, rcu); > } > mutex_unlock(&dpll_lock); >diff --git a/include/linux/dpll.h b/include/linux/dpll.h >index 8ed90dfc65f05..8fff048131f1d 100644 >--- a/include/linux/dpll.h >+++ b/include/linux/dpll.h >@@ -240,6 +240,8 @@ int dpll_device_register(struct dpll_device *dpll, >enum dpll_type type, > void dpll_device_unregister(struct dpll_device *dpll, > const struct dpll_device_ops *ops, void *priv); > >+#define DPLL_PIN_IDX_UNSPEC U32_MAX >+ > struct dpll_pin * > dpll_pin_get(u64 clock_id, u32 dev_driver_id, struct module *module, > const struct dpll_pin_properties *prop); >-- >2.52.0
