From 55adc61c568af99419be1dc0412f8eae019c71f2 Mon Sep 17 00:00:00 2001 From: Lucas Stach Date: Mon, 21 Sep 2015 18:53:57 +0200 Subject: [PATCH] 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 Signed-off-by: Shawn Guo --- drivers/clk/imx/clk.c | 38 ++++++++++++++++++++++++++++++++++++++ drivers/clk/imx/clk.h | 1 + 2 files changed, 39 insertions(+) diff --git a/drivers/clk/imx/clk.c b/drivers/clk/imx/clk.c index df12b5307175..a634b1185be3 100644 --- a/drivers/clk/imx/clk.c +++ b/drivers/clk/imx/clk.c @@ -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); diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h index 1049b0c7d818..c94ac5c26226 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 ** const clks[]); extern void imx_cscmr1_fixup(u32 *val); -- 2.30.2