Re: [PATCH 7/8] drm/sun4i: Add various bits and pieces to enable LVDS support on sun4i

Maxime Ripard
2017-02-13T08:08:27Z

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On Sat, Feb 11, 2017 at 07:44:04PM +0200, Priit Laes wrote:
> TODO: We still rely on u-boot for lvds reset bit setup :(

That needs to be figured out before merging :/

You also have a number of checkpatch warnings / errors that needs to
be fixed.

>
> Signed-off-by: Priit Laes <plaes-q/aMd4JkU83YtjvyW6yDsg@public.gmane.org>
> ---
> drivers/gpu/drm/sun4i/sun4i_lvds.c | 29 ++++++++++++++++++++
> drivers/gpu/drm/sun4i/sun4i_tcon.c | 54 ++++++++++++++++++++++++++++++++------
> drivers/gpu/drm/sun4i/sun4i_tcon.h | 15 +++++++++++
> 3 files changed, 90 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_lvds.c b/drivers/gpu/drm/sun4i/sun4i_lvds.c
> index 2ba4705..de738e5 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_lvds.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_lvds.c
> @@ -114,6 +114,35 @@ static void sun4i_lvds_encoder_enable(struct drm_encoder *encoder)
> /* encoder->bridge can be NULL; drm_bridge_enable checks for it */
> drm_bridge_enable(encoder->bridge);
>
> + /* Enable the LVDS */
> + regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_IF_REG,
> + SUN4I_TCON0_LVDS_IF_ENABLE,
> + SUN4I_TCON0_LVDS_IF_ENABLE);
> +
> + /*
> + * TODO: SUN4I_TCON0_LVDS_ANA0_REG_C and SUN4I_TCON0_LVDS_ANA0_PD
> + * registers span 3 bits, but we only set upper 2 for both
> + * of them based on values taken from Allwinner driver.
> + */
> + regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
> + SUN4I_TCON0_LVDS_ANA0_CK_EN |
> + SUN4I_TCON0_LVDS_ANA0_REG_V |
> + SUN4I_TCON0_LVDS_ANA0_REG_C |
> + SUN4I_TCON0_LVDS_ANA0_EN_MB |
> + SUN4I_TCON0_LVDS_ANA0_PD |
> + SUN4I_TCON0_LVDS_ANA0_DCHS);
> +
> + udelay(2000);
> +
> + regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA1_REG,
> + SUN4I_TCON0_LVDS_ANA1_INIT);
> +
> + udelay(1000);
> +
> + regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA1_REG,
> + SUN4I_TCON0_LVDS_ANA1_UPDATE,
> + SUN4I_TCON0_LVDS_ANA1_UPDATE);
> +
> sun4i_tcon_channel_enable(tcon, 0);

This should be merged in your patch 6.

> }
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> index 71d0087..468a3ce 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> @@ -18,6 +18,7 @@
> #include <drm/drm_panel.h>
>
> #include <linux/component.h>
> +#include <linux/delay.h>
> #include <linux/ioport.h>
> #include <linux/of_address.h>
> #include <linux/of_device.h>
> @@ -29,6 +30,7 @@
> #include "sun4i_crtc.h"
> #include "sun4i_dotclock.h"
> #include "sun4i_drv.h"
> +#include "sun4i_lvds.h"
> #include "sun4i_rgb.h"
> #include "sun4i_tcon.h"
>
> @@ -169,12 +171,29 @@ void sun4i_tcon0_mode_set(struct sun4i_tcon *tcon,
> SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));
>
> /* Set Hsync and Vsync length */
> - hsync = mode->crtc_hsync_end - mode->crtc_hsync_start;
> - vsync = mode->crtc_vsync_end - mode->crtc_vsync_start;
> - DRM_DEBUG_DRIVER("Setting HSYNC %d, VSYNC %d\n", hsync, vsync);
> - regmap_write(tcon->regs, SUN4I_TCON0_BASIC3_REG,
> - SUN4I_TCON0_BASIC3_V_SYNC(vsync) |
> - SUN4I_TCON0_BASIC3_H_SYNC(hsync));
> + if (type != DRM_MODE_ENCODER_LVDS) {
> + // Not needed for LVDS?
> + hsync = mode->crtc_hsync_end - mode->crtc_hsync_start;
> + vsync = mode->crtc_vsync_end - mode->crtc_vsync_start;
> + DRM_DEBUG_DRIVER("Setting HSYNC %d, VSYNC %d\n", hsync, vsync);
> + regmap_write(tcon->regs, SUN4I_TCON0_BASIC3_REG,
> + SUN4I_TCON0_BASIC3_V_SYNC(vsync) |
> + SUN4I_TCON0_BASIC3_H_SYNC(hsync));
> + }

This is your patch 5 (and it would be better to put the condition on
what we know rather than what we assume, we know that it's working for
RGB, but not for anything else).

> +
> + if (type == DRM_MODE_ENCODER_LVDS) {
> + /* Setup bit depth */
> + /* TODO: Figure out where to get display bit depth
> + * val = (1: 18-bit, 0: 24-bit)
> + * TODO: Should we set more registers:
> + * BIT(28) - LVDS_DIRECTION
> + * BIT(27) - LVDS_MODE
> + * BIT(23) - LVDS_CORRECT_MODE
> + */
> + regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_IF_REG,
> + SUN4I_TCON0_LVDS_IF_BITWIDTH,
> + SUN4I_TCON0_LVDS_IF_BITWIDTH);
> + }

And this in your patch 6

>
> /* Setup the polarity of the various signals */
> if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
> @@ -183,8 +202,15 @@ void sun4i_tcon0_mode_set(struct sun4i_tcon *tcon,
> if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
> val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE;
>
> +
> + /* Set proper DCLK phase value */
> + if (type == DRM_MODE_ENCODER_LVDS)
> + val |= SUN4I_TCON0_IO_POL_DCLK_PHASE(1);
> +
> regmap_update_bits(tcon->regs, SUN4I_TCON0_IO_POL_REG,
> - SUN4I_TCON0_IO_POL_HSYNC_POSITIVE | SUN4I_TCON0_IO_POL_VSYNC_POSITIVE,
> + SUN4I_TCON0_IO_POL_HSYNC_POSITIVE |
> + SUN4I_TCON0_IO_POL_VSYNC_POSITIVE |
> + SUN4I_TCON0_IO_POL_DCLK_PHASE_MASK,
> val);

This is covered by your clk_set_phase already.

>
> /* Map output pins to channel 0 */
> @@ -480,6 +506,7 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
> struct drm_device *drm = data;
> struct sun4i_drv *drv = drm->dev_private;
> struct sun4i_tcon *tcon;
> + const char *mode;
> int ret;
>
> tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
> @@ -525,7 +552,18 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
> goto err_free_clocks;
> }
>
> - ret = sun4i_rgb_init(drm);
> + /* Check which output mode is set, defaulting to RGB */
> + ret = of_property_read_string(dev->of_node, "mode", &mode);
> +
> + if (ret || !strcmp(mode, "rgb"))
> + ret = sun4i_rgb_init(drm);
> + else if (!strcmp(mode, "lvds"))
> + ret = sun4i_lvds_init(drm);
> + else {
> + dev_err(dev, "Unknown TCON mode: %s\n", mode);
> + ret = -1;
> + }
> +
> if (ret < 0)
> goto err_free_clocks;
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h
> index b040e10..dc4e350 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.h
> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h
> @@ -69,8 +69,11 @@
> #define SUN4I_TCON0_TTL3_REG 0x7c
> #define SUN4I_TCON0_TTL4_REG 0x80
> #define SUN4I_TCON0_LVDS_IF_REG 0x84
> +#define SUN4I_TCON0_LVDS_IF_ENABLE BIT(31)
> +#define SUN4I_TCON0_LVDS_IF_BITWIDTH BIT(26)
> #define SUN4I_TCON0_IO_POL_REG 0x88
> #define SUN4I_TCON0_IO_POL_DCLK_PHASE(phase) ((phase & 3) << 28)
> +#define SUN4I_TCON0_IO_POL_DCLK_PHASE_MASK (3 << 28)
> #define SUN4I_TCON0_IO_POL_HSYNC_POSITIVE BIT(25)
> #define SUN4I_TCON0_IO_POL_VSYNC_POSITIVE BIT(24)
>
> @@ -128,6 +131,18 @@
> #define SUN4I_TCON_CEU_RANGE_G_REG 0x144
> #define SUN4I_TCON_CEU_RANGE_B_REG 0x148
> #define SUN4I_TCON_MUX_CTRL_REG 0x200
> +#define SUN4I_TCON0_LVDS_ANA0_REG 0x220
> +#define SUN4I_TCON0_LVDS_ANA0_CK_EN BIT(29) | BIT(28)
> +#define SUN4I_TCON0_LVDS_ANA0_REG_V BIT(27) | BIT(26)
> +/* TODO: BIT(23) also belongs to ANA0_REG_C register set */
> +#define SUN4I_TCON0_LVDS_ANA0_REG_C BIT(25) | BIT(24)
> +#define SUN4I_TCON0_LVDS_ANA0_EN_MB BIT(22)
> +/* TODO: BIT(19) also belongs to ANA0_PD register set */

Why don't you set them then?

Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering