diff options
| author | Jacky Bai <ping.bai@nxp.com> | 2025-08-01 15:21:53 +0800 |
|---|---|---|
| committer | Abel Vesa <abel.vesa@linaro.org> | 2025-11-11 17:02:01 +0200 |
| commit | 25b47635f8729e9536d2652774bd509532eaa522 (patch) | |
| tree | 5af198065d94d993aabbdd0c6b213e61f4e2eda3 | |
| parent | 3a8660878839faadb4f1a6dd72c3179c1df56787 (diff) | |
clk: imx: Add some delay before deassert the reset
Some of the PCCs on i.MX8ULP have a sw_rst bit to control the peripheral
reset through SW method. For peripherals like GPU that need sync reset,
some delay is necessary befere & after release the reset to make sure the
HW is reset into a known status. So add some delay before & after release
reset.
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20250801072153.1974428-1-ping.bai@nxp.com
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
| -rw-r--r-- | drivers/clk/imx/clk-composite-7ulp.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/clk/imx/clk-composite-7ulp.c b/drivers/clk/imx/clk-composite-7ulp.c index 8ed2e0ad2769..37d2fc197be6 100644 --- a/drivers/clk/imx/clk-composite-7ulp.c +++ b/drivers/clk/imx/clk-composite-7ulp.c @@ -7,6 +7,7 @@ #include <linux/bits.h> #include <linux/clk-provider.h> +#include <linux/delay.h> #include <linux/err.h> #include <linux/io.h> #include <linux/slab.h> @@ -36,6 +37,9 @@ static int pcc_gate_enable(struct clk_hw *hw) if (ret) return ret; + /* Make sure the IP's clock is ready before release reset */ + udelay(1); + spin_lock_irqsave(gate->lock, flags); /* * release the sw reset for peripherals associated with @@ -47,6 +51,15 @@ static int pcc_gate_enable(struct clk_hw *hw) spin_unlock_irqrestore(gate->lock, flags); + /* + * Read back the register to make sure the previous write has been + * done in the target HW register. For IP like GPU, after deassert + * the reset, need to wait for a while to make sure the sync reset + * is done + */ + readl(gate->reg); + udelay(1); + return 0; } |