Re: [PATCH v4 5/8] drm/mediatek: add dsi interrupt control

[CK Hu <ck.hu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>]

Hi, YT:

Some comments inline.

On Fri, 2016-07-15 at 18:07 +0800, YT Shen wrote:
> From: shaoming chen <shaoming.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> 
> add dsi interrupt control
> 
> Signed-off-by: shaoming chen <shaoming.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c |  130 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 130 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 2d808e5..de5ad7f 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -18,6 +18,7 @@
>  #include <drm/drm_panel.h>
>  #include <linux/clk.h>
>  #include <linux/component.h>
> +#include <linux/irq.h>
>  #include <linux/of.h>
>  #include <linux/of_platform.h>
>  #include <linux/of_graph.h>
> @@ -32,6 +33,13 @@
>  
>  #define DSI_START		0x00
>  
> +#define DSI_INTEN		0x08
> +
> +#define DSI_INTSTA		0x0c
> +#define LPRX_RD_RDY_INT_FLAG	BIT(0)
> +#define CMD_DONE_INT_FLAG	BIT(1)
> +#define DSI_BUSY		BIT(31)

Why need LPRX_RD_RDY_INT_FLAG, CMD_DONE_INT_FLAG, and DSI_BUSY? Maybe
these three should be moved to other patch.

> +
>  #define DSI_CON_CTRL		0x10
>  #define DSI_RESET			BIT(0)
>  #define DSI_EN				BIT(1)
> @@ -74,6 +82,9 @@
>  
>  #define DSI_HSTX_CKL_WC		0x64
>  
> +#define DSI_RACK		0x84
> +#define RACK			BIT(0)
> +
>  #define DSI_PHY_LCCON		0x104
>  #define LC_HS_TX_EN			BIT(0)
>  #define LC_ULPM_EN			BIT(1)
> @@ -134,6 +145,18 @@ struct mtk_dsi {
>  	struct videomode vm;
>  	int refcount;
>  	bool enabled;
> +	int irq_num, irq_data;
> +};
> +
> +enum {
> +	DSI_INT_SLEEPOUT_DONE_FLAG	= BIT(6),
> +	DSI_INT_VM_CMD_DONE_FLAG	= BIT(5),
> +	DSI_INT_EXT_TE_RDY_FLAG		= BIT(4),
> +	DSI_INT_VM_DONE_FLAG		= BIT(3),
> +	DSI_INT_TE_RDY_FLAG		= BIT(2),
> +	DSI_INT_CMD_DONE_FLAG		= BIT(1),
> +	DSI_INT_LPRX_RD_RDY_FLAG	= BIT(0),
> +	DSI_INT_ALL_BITS		= (0x7f)
>  };

I think you should use '#define' instead of 'enum'. The code would be
like below, and these definition should be moved to after DSI_INTEN or
DSI_INTSTA.

#define DSI_INT_LPRX_RD_RDY_FLAG	BIT(0)
#define DSI_INT_CMD_DONE_FLAG		BIT(1)
#define DSI_INT_TE_RDY_FLAG		BIT(2)
#define DSI_INT_VM_DONE_FLAG		BIT(3)
#define DSI_INT_EXT_TE_RDY_FLAG		BIT(4)
#define DSI_INT_VM_CMD_DONE_FLAG	BIT(5)
#define DSI_INT_SLEEPOUT_DONE_FLAG	BIT(6)
#define DSI_INT_ALL_BITS		(DSI_INT_LPRX_RD_RDY_FLAG | \
					DSI_INT_CMD_DONE_FLAG | \
					DSI_INT_TE_RDY_FLAG | \
					DSI_INT_VM_DONE_FLAG | \
					DSI_INT_EXT_TE_RDY_FLAG | \
					DSI_INT_VM_CMD_DONE_FLAG | \
					DSI_INT_SLEEPOUT_DONE_FLAG)

>  
>  static inline struct mtk_dsi *encoder_to_dsi(struct drm_encoder *e)
> @@ -440,6 +463,94 @@ static void mtk_dsi_start(struct mtk_dsi *dsi)
>  	writel(1, dsi->regs + DSI_START);
>  }
>  
> +static void mtk_dsi_set_interrupt_enable(struct mtk_dsi *dsi)
> +{
> +	u32 inten = DSI_INT_ALL_BITS;
> +
> +	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO)
> +		inten &= ~(DSI_INT_TE_RDY_FLAG | DSI_INT_EXT_TE_RDY_FLAG);
> +
> +	writel(inten, dsi->regs + DSI_INTEN);
> +}
> +
> +static void mtk_dsi_irq_wakeup(struct mtk_dsi *dsi, u32 irq_bit)
> +{
> +	dsi->irq_data |= irq_bit;
> +}
> +
> +static irqreturn_t mtk_dsi_irq(int irq, void *dev_id)
> +{
> +	struct mtk_dsi *dsi = dev_id;
> +
> +	u32 status, tmp;
> +
> +	status = readl(dsi->regs + DSI_INTSTA);
> +
> +	if (status & DSI_INT_LPRX_RD_RDY_FLAG) {
> +		/* write clear RD_RDY interrupt */
> +		/* write clear RD_RDY interrupt must be before DSI_RACK */
> +		/* because CMD_DONE will raise after DSI_RACK, */
> +		/* so write clear RD_RDY after that will clear CMD_DONE too */
> +		do {
> +			/* send read ACK */
> +			mtk_dsi_mask(dsi, DSI_RACK, RACK, RACK);
> +			tmp = readl(dsi->regs + DSI_INTSTA);
> +		} while (tmp & DSI_BUSY);
> +
> +		mtk_dsi_mask(dsi, DSI_INTSTA, DSI_INT_LPRX_RD_RDY_FLAG, 0);
> +		mtk_dsi_irq_wakeup(dsi, DSI_INT_LPRX_RD_RDY_FLAG);
> +	}
> +
> +	if (status & DSI_INT_CMD_DONE_FLAG) {
> +		mtk_dsi_mask(dsi, DSI_INTSTA, DSI_INT_CMD_DONE_FLAG, 0);
> +		mtk_dsi_irq_wakeup(dsi, DSI_INT_CMD_DONE_FLAG);
> +	}
> +
> +	if (status & DSI_INT_TE_RDY_FLAG) {
> +		mtk_dsi_mask(dsi, DSI_INTSTA, DSI_INT_TE_RDY_FLAG, 0);
> +		mtk_dsi_irq_wakeup(dsi, DSI_INT_TE_RDY_FLAG);
> +	}
> +
> +	if (status & DSI_INT_VM_DONE_FLAG) {
> +		mtk_dsi_mask(dsi, DSI_INTSTA, DSI_INT_VM_DONE_FLAG, 0);
> +		mtk_dsi_irq_wakeup(dsi, DSI_INT_VM_DONE_FLAG);
> +	}
> +
> +	if (status & DSI_INT_EXT_TE_RDY_FLAG) {
> +		mtk_dsi_mask(dsi, DSI_INTSTA, DSI_INT_EXT_TE_RDY_FLAG, 0);
> +		mtk_dsi_irq_wakeup(dsi, DSI_INT_EXT_TE_RDY_FLAG);
> +	}
> +
> +	if (status & DSI_INT_VM_CMD_DONE_FLAG) {
> +		mtk_dsi_mask(dsi, DSI_INTSTA, DSI_INT_VM_CMD_DONE_FLAG, 0);
> +		mtk_dsi_irq_wakeup(dsi, DSI_INT_VM_CMD_DONE_FLAG);
> +	}
> +
> +	if (status & DSI_INT_SLEEPOUT_DONE_FLAG) {
> +		mtk_dsi_mask(dsi, DSI_INTSTA, DSI_INT_SLEEPOUT_DONE_FLAG, 0);
> +		mtk_dsi_irq_wakeup(dsi, DSI_INT_SLEEPOUT_DONE_FLAG);
> +	}

All these 'if' statement do the same thing and I think these could be
merge as:

status = readl(dsi->regs + DSI_INTSTA) & DSI_INT_ALL_BITS);
if (status) {
	mtk_dsi_mask(dsi, DSI_INTSTA, status, 0);
	mtk_dsi_irq_wakeup(dsi, status);
}

> +
> +	return IRQ_HANDLED;
> +}
> +
> +static s32 mtk_dsi_wait_for_irq_timeout(struct mtk_dsi *dsi, u32 irq_bit,
> +					u32 timeout_ms)
> +{
> +	while (timeout_ms--) {
> +		if (dsi->irq_data & irq_bit) {
> +			dsi->irq_data &= ~irq_bit;
> +			return 0;
> +		}
> +
> +		usleep_range(1000, 1100);
> +	}

I think it's better to use wait_event() or something else. Polling with
sleep could not react immediately.

> +
> +	dsi->irq_data = 0;

Why clear all bit after wait one bit timeout?

> +
> +	return -1;
> +}
> +
>  static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
>  {
>  	if (WARN_ON(dsi->refcount == 0))
> @@ -488,6 +599,7 @@ static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
>  
>  	dsi_ps_control_vact(dsi);
>  	dsi_config_vdo_timing(dsi);
> +	mtk_dsi_set_interrupt_enable(dsi);
>  
>  	dsi_set_mode(dsi);
>  	dsi_clk_hs_mode(dsi, 1);
> @@ -883,6 +995,24 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	dsi->irq_num = platform_get_irq(pdev, 0);

You use irq_num only in this function, why keep it in dsi structure?

> +	if (dsi->irq_num < 0) {
> +		dev_err(&pdev->dev, "failed to request dsi irq resource\n");
> +		ret = dsi->irq_num;
> +		return -EPROBE_DEFER;
> +	}
> +
> +	irq_set_status_flags(dsi->irq_num, IRQ_TYPE_LEVEL_LOW);
> +	ret = devm_request_irq(&pdev->dev, dsi->irq_num, mtk_dsi_irq,
> +			       IRQF_TRIGGER_LOW, dev_name(&pdev->dev), dsi);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to request mediatek dsi irq\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	dsi->irq_data = 0;
> +	dev_info(dev, "dsi irq num is 0x%x\n", dsi->irq_num);
> +
>  	platform_set_drvdata(pdev, dsi);
>  
>  	return component_add(&pdev->dev, &mtk_dsi_component_ops);

Regards,
CK

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