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: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This commit is contained in:
Lucas Stach 2015-09-21 18:53:57 +02:00 committed by Shawn Guo
parent 8d449cb5e2
commit 55adc61c56
2 changed files with 39 additions and 0 deletions

View File

@ -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);

View File

@ -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);