diff mbox series

[v2,3/3] clk: xilinx: vcu: Update vcu init/reset sequence

Message ID 20250102170359.761670-4-rohit.visavalia@amd.com (mailing list archive)
State New
Headers show
Series clk: xilinx: vcu: Sequence update and couple of fixes | expand

Commit Message

Visavalia, Rohit Jan. 2, 2025, 5:03 p.m. UTC 
Updated vcu init/reset sequence as per design changes.
If VCU reset GPIO is available then do assert and de-assert it before
enabling/disabling gasket isolation.
This GPIO is added because gasket isolation will be removed during startup
that requires access to SLCR register space. Post startup, the ownership of
the register interface lies with logiCORE IP.

Signed-off-by: Rohit Visavalia <rohit.visavalia@amd.com>
---
Changes in v2:
  - Changed patches sequence to have patches with "Fixes" as preceding in order
  - Used dev_err_probe()
  - Moved warning to dev_dbg() and updated print with more detail
  - Link to v1: https://lore.kernel.org/linux-clk/20241226122023.3439559-2-rohit.visavalia@amd.com/ 
---
 drivers/clk/xilinx/xlnx_vcu.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

Comments

Geert Uytterhoeven Jan. 2, 2025, 7:30 p.m. UTC | #1 
Hi Rohit,

On Thu, Jan 2, 2025 at 6:04 PM Rohit Visavalia <rohit.visavalia@amd.com> wrote:
> Updated vcu init/reset sequence as per design changes.
> If VCU reset GPIO is available then do assert and de-assert it before
> enabling/disabling gasket isolation.
> This GPIO is added because gasket isolation will be removed during startup
> that requires access to SLCR register space. Post startup, the ownership of
> the register interface lies with logiCORE IP.
>
> Signed-off-by: Rohit Visavalia <rohit.visavalia@amd.com>
> ---
> Changes in v2:
>   - Changed patches sequence to have patches with "Fixes" as preceding in order
>   - Used dev_err_probe()
>   - Moved warning to dev_dbg() and updated print with more detail

Thanks for the update!

> --- a/drivers/clk/xilinx/xlnx_vcu.c
> +++ b/drivers/clk/xilinx/xlnx_vcu.c
> @@ -676,6 +679,24 @@ static int xvcu_probe(struct platform_device *pdev)
>          * Bit 0 : Gasket isolation
>          * Bit 1 : put VCU out of reset
>          */
> +       xvcu->reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
> +                                                  GPIOD_OUT_LOW);

This requires updating the DT bindings _first_.

> +       if (IS_ERR(xvcu->reset_gpio)) {
> +               ret = PTR_ERR(xvcu->reset_gpio);
> +               dev_err_probe(&pdev->dev, ret, "failed to get reset gpio for vcu.\n");
> +               goto error_get_gpio;
> +       }
> +
> +       if (xvcu->reset_gpio) {
> +               gpiod_set_value(xvcu->reset_gpio, 0);
> +               /* min 2 clock cycle of vcu pll_ref, slowest freq is 33.33KHz */
> +               usleep_range(60, 120);
> +               gpiod_set_value(xvcu->reset_gpio, 1);
> +               usleep_range(60, 120);
> +       } else {
> +               dev_dbg(&pdev->dev, "No reset gpio info found in dts for VCU. This may result in incorrect functionality if VCU isolation is removed after initialization in designs where the VCU reset is driven by gpio.\n");
> +       }
> +
>         regmap_write(xvcu->logicore_reg_ba, VCU_GASKET_INIT, VCU_GASKET_VALUE);
>
>         ret = xvcu_register_clock_provider(xvcu);

Gr{oetje,eeting}s,

                        Geert
diff mbox series

Patch

diff --git a/drivers/clk/xilinx/xlnx_vcu.c b/drivers/clk/xilinx/xlnx_vcu.c
index c520ae1ba65e..50f7c3ecb07c 100644
--- a/drivers/clk/xilinx/xlnx_vcu.c
+++ b/drivers/clk/xilinx/xlnx_vcu.c
@@ -11,6 +11,7 @@ 
 #include <linux/clk-provider.h>
 #include <linux/device.h>
 #include <linux/errno.h>
+#include <linux/gpio/consumer.h>
 #include <linux/io.h>
 #include <linux/mfd/syscon.h>
 #include <linux/mfd/syscon/xlnx-vcu.h>
@@ -51,6 +52,7 @@ 
  * @dev: Platform device
  * @pll_ref: pll ref clock source
  * @aclk: axi clock source
+ * @reset_gpio: vcu reset gpio
  * @logicore_reg_ba: logicore reg base address
  * @vcu_slcr_ba: vcu_slcr Register base address
  * @pll: handle for the VCU PLL
@@ -61,6 +63,7 @@  struct xvcu_device {
 	struct device *dev;
 	struct clk *pll_ref;
 	struct clk *aclk;
+	struct gpio_desc *reset_gpio;
 	struct regmap *logicore_reg_ba;
 	void __iomem *vcu_slcr_ba;
 	struct clk_hw *pll;
@@ -676,6 +679,24 @@  static int xvcu_probe(struct platform_device *pdev)
 	 * Bit 0 : Gasket isolation
 	 * Bit 1 : put VCU out of reset
 	 */
+	xvcu->reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
+						   GPIOD_OUT_LOW);
+	if (IS_ERR(xvcu->reset_gpio)) {
+		ret = PTR_ERR(xvcu->reset_gpio);
+		dev_err_probe(&pdev->dev, ret, "failed to get reset gpio for vcu.\n");
+		goto error_get_gpio;
+	}
+
+	if (xvcu->reset_gpio) {
+		gpiod_set_value(xvcu->reset_gpio, 0);
+		/* min 2 clock cycle of vcu pll_ref, slowest freq is 33.33KHz */
+		usleep_range(60, 120);
+		gpiod_set_value(xvcu->reset_gpio, 1);
+		usleep_range(60, 120);
+	} else {
+		dev_dbg(&pdev->dev, "No reset gpio info found in dts for VCU. This may result in incorrect functionality if VCU isolation is removed after initialization in designs where the VCU reset is driven by gpio.\n");
+	}
+
 	regmap_write(xvcu->logicore_reg_ba, VCU_GASKET_INIT, VCU_GASKET_VALUE);
 
 	ret = xvcu_register_clock_provider(xvcu);
@@ -690,6 +711,7 @@  static int xvcu_probe(struct platform_device *pdev)
 
 error_clk_provider:
 	xvcu_unregister_clock_provider(xvcu);
+error_get_gpio:
 	clk_disable_unprepare(xvcu->aclk);
 	return ret;
 }
@@ -711,6 +733,13 @@  static void xvcu_remove(struct platform_device *pdev)
 	xvcu_unregister_clock_provider(xvcu);
 
 	/* Add the Gasket isolation and put the VCU in reset. */
+	if (xvcu->reset_gpio) {
+		gpiod_set_value(xvcu->reset_gpio, 0);
+		/* min 2 clock cycle of vcu pll_ref, slowest freq is 33.33KHz */
+		usleep_range(60, 120);
+		gpiod_set_value(xvcu->reset_gpio, 1);
+		usleep_range(60, 120);
+	}
 	regmap_write(xvcu->logicore_reg_ba, VCU_GASKET_INIT, 0);
 
 	clk_disable_unprepare(xvcu->aclk);