Commit 55adc61c authored by Lucas Stach's avatar Lucas Stach Committed by Shawn Guo
Browse files

clk: imx: add common logic to detect early UART usage 



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: default avatarLucas Stach <l.stach@pengutronix.de>
Signed-off-by: default avatarShawn Guo <shawnguo@kernel.org>
parent 8d449cb5

drivers/clk/imx/clk.c

+38 −0
Original line number Diff line number Diff line
@@ -73,3 +73,41 @@ void imx_cscmr1_fixup(u32 *val) 
	*val ^= CSCMR1_FIXUP;

	return;

}



static int imx_keep_uart_clocks __initdata;

static struct clk ** const *imx_uart_clocks __initdata;



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 ** const clks[])

{

	if (imx_keep_uart_clocks) {

		int i;



		imx_uart_clocks = clks;

		for (i = 0; imx_uart_clocks[i]; i++)

			clk_prepare_enable(*imx_uart_clocks[i]);

	}

}



static int __init imx_clk_disable_uart(void)

{

	if (imx_keep_uart_clocks && imx_uart_clocks) {

		int i;



		for (i = 0; imx_uart_clocks[i]; i++)

			clk_disable_unprepare(*imx_uart_clocks[i]);

	}



	return 0;

}

late_initcall_sync(imx_clk_disable_uart);

drivers/clk/imx/clk.h

+1 −0
Original line number Diff line number Diff line
@@ -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 ** const clks[]);



extern void imx_cscmr1_fixup(u32 *val);

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