[PATCH v3 1/5] usb: dwc3: Cache ref_clk pointer in struct dwc3

[Marek Vasut]

Cache ref_clk clock pointer in struct dwc3 . This is a preparatory
patch for subsequent backports from Linux kernel which configure
GFLADJ register content based on the ref_clk rate and therefore need
access to the ref_clk pointer.

It is possible to extract the clock pointer from existing clk_bulk
list of already claimed clock, no need to call clk_get*() again.

Reviewed-by: Sean Anderson <seanga2 at gmail.com>
Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Angus Ainslie <angus at akkea.ca>
Cc: Bin Meng <bmeng.cn at gmail.com>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Kunihiko Hayashi <hayashi.kunihiko at socionext.com>
Cc: Michal Simek <michal.simek at xilinx.com>
Cc: Peng Fan <peng.fan at nxp.com>
Cc: Sean Anderson <sean.anderson at seco.com>
Cc: Stefano Babic <sbabic at denx.de>
---
V2: Add paragraph on clk_get into commit message
V3: No change
---
 drivers/usb/dwc3/core.h         | 3 +++
 drivers/usb/dwc3/dwc3-generic.c | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index d7cce3a861a..0d20fe285b0 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -668,6 +668,7 @@ struct dwc3_scratchpad_array {
  * @event_buffer_list: a list of event buffers
  * @gadget: device side representation of the peripheral controller
  * @gadget_driver: pointer to the gadget driver
+ * @ref_clk: reference clock
  * @regs: base address for our registers
  * @regs_size: address space size
  * @nr_scratch: number of scratch buffers
@@ -766,6 +767,8 @@ struct dwc3 {
 	struct usb_gadget	gadget;
 	struct usb_gadget_driver *gadget_driver;
 
+	struct clk		*ref_clk;
+
 	void __iomem		*regs;
 	size_t			regs_size;
 
diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c
index 466b25a0c38..78966718d01 100644
--- a/drivers/usb/dwc3/dwc3-generic.c
+++ b/drivers/usb/dwc3/dwc3-generic.c
@@ -59,12 +59,21 @@ static int dwc3_generic_probe(struct udevice *dev,
 	struct dwc3_generic_plat *plat = dev_get_plat(dev);
 	struct dwc3 *dwc3 = &priv->dwc3;
 	struct dwc3_glue_data *glue = dev_get_plat(dev->parent);
+	int __maybe_unused index;
+	ofnode __maybe_unused node;
 
 	dwc3->dev = dev;
 	dwc3->maximum_speed = plat->maximum_speed;
 	dwc3->dr_mode = plat->dr_mode;
 #if CONFIG_IS_ENABLED(OF_CONTROL)
 	dwc3_of_parse(dwc3);
+
+	node = dev_ofnode(dev->parent);
+	index = ofnode_stringlist_search(node, "clock-names", "ref");
+	if (index < 0)
+		index = ofnode_stringlist_search(node, "clock-names", "ref_clk");
+	if (index >= 0)
+		dwc3->ref_clk = &glue->clks.clks[index];
 #endif
 
 	/*
-- 
2.35.1