Re: [PATCH v6 4/5] clk: aspeed: Register gated clocks
From: Stephen Boyd
Date: Thu Dec 21 2017 - 18:39:38 EST
On 11/28, Joel Stanley wrote:
> diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c
> index 839243691b26..b5dc3e298693 100644
> --- a/drivers/clk/clk-aspeed.c
> +++ b/drivers/clk/clk-aspeed.c
> @@ -202,6 +202,107 @@ static const struct aspeed_clk_soc_data ast2400_data = {
> .calc_pll = aspeed_ast2400_calc_pll,
> };
>
> +static int aspeed_clk_enable(struct clk_hw *hw)
> +{
> + struct aspeed_clk_gate *gate = to_aspeed_clk_gate(hw);
> + unsigned long flags;
> + u32 clk = BIT(gate->clock_idx);
> + u32 rst = BIT(gate->reset_idx);
> +
> + spin_lock_irqsave(gate->lock, flags);
> +
> + if (gate->reset_idx >= 0) {
> + /* Put IP in reset */
> + regmap_update_bits(gate->map, ASPEED_RESET_CTRL, rst, rst);
> +
> + /* Delay 100us */
> + udelay(100);
> + }
> +
> + /* Enable clock */
> + regmap_update_bits(gate->map, ASPEED_CLK_STOP_CTRL, clk, 0);
> +
> + if (gate->reset_idx >= 0) {
> + /* Delay 10ms */
> + /* TODO: can we sleep here? */
> + msleep(10);
No you can't sleep here. It needs to delay because this is inside
spinlock_irqsave.
> +
> + /* Take IP out of reset */
> + regmap_update_bits(gate->map, ASPEED_RESET_CTRL, rst, 0);
> + }
> +
> + spin_unlock_irqrestore(gate->lock, flags);
> +
> + return 0;
> +}
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project