[U-Boot] [PATCH V2 09/14] video: mxsfb: introduce lcdif_power_down

Stefano Babic
2015-10-20T13:59:18Z

Hi Peng,

On 20/10/2015 13:39, Peng Fan wrote:
> Introudce a new function lcdif_power_down.
>
> 1. Waits for a VSYNC interrupt to guarantee the reset is done at the
> VSYNC edge, which somehow makes the LCDIF consume the display FIFO(?)
> and helps the LCDIF work normally at the kernel stage.
> 2. Add power down function to stop lcdif.
>
> The reason to introduce lcdif_power_down is that we want lcdif to be in
> initial state when doing uboot reset or before kernel boot to make
> system stable, otherwise system may hang.
>

The explanation is independent from the processor type. But checking in
the next patch, this code runs only for 6UL. Why not for the 6sx ?

> Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
> Cc: Stefano Babic <sbabic@denx.de>
> Cc: Anatolij Gustschin <agust@denx.de>
> ---
>
> V2:
> none
>
> arch/arm/include/asm/imx-common/sys_proto.h | 2 ++
> drivers/video/mxsfb.c | 17 +++++++++++++++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/arch/arm/include/asm/imx-common/sys_proto.h b/arch/arm/include/asm/imx-common/sys_proto.h
> index 5673fb4..386c2dc 100644
> --- a/arch/arm/include/asm/imx-common/sys_proto.h
> +++ b/arch/arm/include/asm/imx-common/sys_proto.h
> @@ -47,6 +47,8 @@ int fecmxc_initialize(bd_t *bis);
> u32 get_ahb_clk(void);
> u32 get_periph_clk(void);
>
> +void lcdif_power_down(void);
> +
> int mxs_reset_block(struct mxs_register_32 *reg);
> int mxs_wait_mask_set(struct mxs_register_32 *reg, u32 mask, u32 timeout);
> int mxs_wait_mask_clr(struct mxs_register_32 *reg, u32 mask, u32 timeout);
> diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
> index eed57d5..ddbb118 100644
> --- a/drivers/video/mxsfb.c
> +++ b/drivers/video/mxsfb.c
> @@ -131,6 +131,23 @@ static void mxs_lcd_init(GraphicDevice *panel,
> writel(LCDIF_CTRL_RUN, &regs->hw_lcdif_ctrl_set);
> }
>
> +void lcdif_power_down(void)
> +{
> + struct mxs_lcdif_regs *regs = (struct mxs_lcdif_regs *)MXS_LCDIF_BASE;
> + int timeout = 1000000;
> +
> + writel(panel.frameAdrs, &regs->hw_lcdif_cur_buf_reg);
> + writel(panel.frameAdrs, &regs->hw_lcdif_next_buf_reg);
> + writel(LCDIF_CTRL1_VSYNC_EDGE_IRQ, &regs->hw_lcdif_ctrl1_clr);
> + while (--timeout) {
> + if (readl(&regs->hw_lcdif_ctrl1_reg) &
> + LCDIF_CTRL1_VSYNC_EDGE_IRQ)
> + break;
> + udelay(1);
> + }
> + mxs_reset_block((struct mxs_register_32 *)&regs->hw_lcdif_ctrl_reg);
> +}
> +
> void *video_hw_init(void)
> {
> int bpp = -1;
>

Best regards,
Stefano Babic

--
=====================================================================
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================