Add the ability to enable optional slot clock into the pwrctrl driver.
This is used to enable slot clock in split-clock topologies, where the
PCIe host/controller supply and PCIe slot supply are not provided by
the same clock. The PCIe host/controller clock should be described in
the controller node as the controller clock, while the slot clock should
be described in controller bridge/slot subnode.
Example DT snippet:
&pcicontroller {
clocks = <&clk_dif 0>; /* PCIe controller clock */
pci@0,0 {
#address-cells = <3>;
#size-cells = <2>;
reg = <0x0 0x0 0x0 0x0 0x0>;
compatible = "pciclass,0604";
device_type = "pci";
clocks = <&clk_dif 1>; /* PCIe slot clock */
vpcie3v3-supply = <®_3p3v>;
ranges;
};
};
Example clock topology:
____________ ____________
| PCIe host | | PCIe slot |
| | | |
| PCIe RX<|==================|>PCIe TX |
| PCIe TX<|==================|>PCIe RX |
| | | |
| PCIe CLK<|======.. ..======|>PCIe CLK |
'------------' || || '------------'
|| ||
____________ || ||
| 9FGV0441 | || ||
| | || ||
| CLK DIF0<|======'' ||
| CLK DIF1<|==========''
| CLK DIF2<|
| CLK DIF3<|
'------------'
Reviewed-by: Anand Moon <linux.amoon@xxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxxxx>
---
Cc: Bartosz Golaszewski <brgl@xxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Conor Dooley <conor+dt@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Cc: Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>
Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-pci@xxxxxxxxxxxxxxx
Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
---
V2: - Fold PTR_ERR() into dev_err_probe()
- Add RB from Anand and Manivannan
---
drivers/pci/pwrctrl/slot.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/pci/pwrctrl/slot.c b/drivers/pci/pwrctrl/slot.c
index 18becc144913e..dac1ae854f72e 100644
--- a/drivers/pci/pwrctrl/slot.c
+++ b/drivers/pci/pwrctrl/slot.c
@@ -4,6 +4,7 @@
* Author: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
*/
+#include <linux/clk.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
@@ -30,6 +31,7 @@ static int pci_pwrctrl_slot_probe(struct platform_device *pdev)
{
struct pci_pwrctrl_slot_data *slot;
struct device *dev = &pdev->dev;
+ struct clk *clk;
int ret;
slot = devm_kzalloc(dev, sizeof(*slot), GFP_KERNEL);
@@ -50,6 +52,13 @@ static int pci_pwrctrl_slot_probe(struct platform_device *pdev)
goto err_regulator_free;
}
+ clk = devm_clk_get_optional_enabled(dev, NULL);
+ if (IS_ERR(clk)) {
+ ret = dev_err_probe(dev, PTR_ERR(clk),
+ "Failed to enable slot clock\n");
+ goto err_regulator_disable;
+ }
+
ret = devm_add_action_or_reset(dev, devm_pci_pwrctrl_slot_power_off,
slot);
if (ret)
--
2.47.2
