Subject: [PATCH v2 1/8] clk: imx: add common logic to detect early UART usage

From: [email-masked] (Shawn Guo)
Date: Sun, 6 Sep 2015 22:21:24 +0800

On Fri, Sep 04, 2015 at 06:00:12PM +0200, Lucas Stach wrote:
> Both earlycon and eralyprintk depend on the bootloader setup UART
> clocks being retained. This patch adds the common logic to detect such
> situations and make the information available to the clock drivers, as
> well as adding the facilities to disable those clocks at the end of
> the kernel init.
> 
> Signed-off-by: Lucas Stach <[email-masked]>
> ---
>  drivers/clk/imx/clk.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/clk/imx/clk.h |  1 +
>  2 files changed, 47 insertions(+)
> 
> diff --git a/drivers/clk/imx/clk.c b/drivers/clk/imx/clk.c
> index df12b5307175..3357e29e43ab 100644
> --- a/drivers/clk/imx/clk.c
> +++ b/drivers/clk/imx/clk.c
> @@ -73,3 +73,49 @@ void imx_cscmr1_fixup(u32 *val)
>  	*val ^= CSCMR1_FIXUP;
>  	return;
>  }
> +
> +static int __initdata imx_keep_uart_clocks;

This gives a checkpatch warning as below.

WARNING: __initdata should be placed after imx_keep_uart_clocks
#27: FILE: drivers/clk/imx/clk.c:77:
+static int __initdata imx_keep_uart_clocks;

Shawn

> +static struct clk __initdata ***imx_uart_clocks;
> +
> +static int __init imx_keep_uart_clocks_param(char *str)
> +{
> +	imx_keep_uart_clocks = 1;
> +
> +	return 0;
> +}
> +__setup_param("earlycon", imx_keep_uart_earlycon,
> +	      imx_keep_uart_clocks_param, 0);
> +__setup_param("earlyprintk", imx_keep_uart_earlyprintk,
> +	      imx_keep_uart_clocks_param, 0);
> +
> +void __init imx_register_uart_clocks(struct clk **clks[])
> +{
> +	if (imx_keep_uart_clocks) {
> +		int i;
> +
> +		imx_uart_clocks = clks;
> +		for (i = 0;; i++) {
> +			if (imx_uart_clocks[i])
> +				clk_prepare_enable(*imx_uart_clocks[i]);
> +			else
> +				break;
> +		}
> +	}
> +}
> +
> +static int __init imx_clk_disable_uart(void)
> +{
> +	if (imx_keep_uart_clocks) {
> +		int i;
> +
> +		for (i = 0;; i++) {
> +			if (imx_uart_clocks[i])
> +				clk_disable_unprepare(*imx_uart_clocks[i]);
> +			else
> +				break;
> +		}
> +	}
> +
> +	return 0;
> +}
> +late_initcall_sync(imx_clk_disable_uart);
> diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
> index 1049b0c7d818..c4e2e282e892 100644
> --- a/drivers/clk/imx/clk.h
> +++ b/drivers/clk/imx/clk.h
> @@ -7,6 +7,7 @@
>  extern spinlock_t imx_ccm_lock;
>  
>  void imx_check_clocks(struct clk *clks[], unsigned int count);
> +void imx_register_uart_clocks(struct clk **clks[]);
>  
>  extern void imx_cscmr1_fixup(u32 *val);
>  
> -- 
> 2.5.0
>