[U-Boot] [PATCH 0/6] am335x-fb: support display PLL for lcd-clock / pixel-clock

[U-Boot] [PATCH 0/6] am335x-fb: support display PLL for lcd-clock / pixel-clock

[Hannes Schmelzer]

In most cases days ago the LCDC IP-core clock on AM335x was sourced from
the peripheral PLL with 192 MHz and the pixel clock for the connected
lcd-screen was made more or less accurate with a divider inside LCDC IP-
core.

For certain displays, example a standard VGA with 25.17 MHz pixelclock,
it is almost impossible to generate a reasonably clock with the 192 MHz
base and a simple divider. For those cases we have to use the dedicated
DPLL_DISP generating a dividable clock-source for the LCDC.

This series does this with following steps:
- adding register definition of the display PLL to clock_am33xx
- calculate mult, dividers with lowest error and setup the display PLL,
selecting as clock-source for LCDC the display PLL.
- drop the hardcoded dependency in BuR/common to the 192 MHz and
provide a real clock-frequency instead a divider
- drop the clock selection for the LCDC within board code
- do minor cosmetic cleanups (updating copyright, coding style)


Hannes Schmelzer (6):
  mach-omap2: add AM335x Display PLL register definition
  am335x-fb: cosmetic: update-copyright
  am335x-fb: cosmetic: fix coding style
  am335x-fb: setup display PLL
  board/BuR: provide real clock-frequency instead a divider
  board/BuR: drop LCDC clock manipulation from board code

 arch/arm/include/asm/arch-am33xx/clock.h  |  1 +
 arch/arm/mach-omap2/am33xx/clock_am33xx.c |  7 ++++
 board/BuR/brppt1/board.c                  |  3 --
 board/BuR/brxre1/board.c                  |  2 -
 board/BuR/common/common.c                 | 14 ++-----
 drivers/video/am335x-fb.c                 | 64 +++++++++++++++++++++++++++----
 drivers/video/am335x-fb.h                 |  6 +--
 7 files changed, 71 insertions(+), 26 deletions(-)

-- 
2.7.4

[U-Boot] [PATCH 1/6] mach-omap2: add AM335x Display PLL register definition

[Hannes Schmelzer]

Adds the register definition of the Display DPLL

Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>

---

 arch/arm/include/asm/arch-am33xx/clock.h  | 1 +
 arch/arm/mach-omap2/am33xx/clock_am33xx.c | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/arch/arm/include/asm/arch-am33xx/clock.h b/arch/arm/include/asm/arch-am33xx/clock.h
index 5399bb8..9dbcd3a 100644
--- a/arch/arm/include/asm/arch-am33xx/clock.h
+++ b/arch/arm/include/asm/arch-am33xx/clock.h
@@ -104,6 +104,7 @@ extern const struct dpll_regs dpll_mpu_regs;
 extern const struct dpll_regs dpll_core_regs;
 extern const struct dpll_regs dpll_per_regs;
 extern const struct dpll_regs dpll_ddr_regs;
+extern const struct dpll_regs dpll_disp_regs;
 extern const struct dpll_params dpll_mpu_opp[NUM_CRYSTAL_FREQ][NUM_OPPS];
 extern const struct dpll_params dpll_core_1000MHz[NUM_CRYSTAL_FREQ];
 extern const struct dpll_params dpll_per_192MHz[NUM_CRYSTAL_FREQ];
diff --git a/arch/arm/mach-omap2/am33xx/clock_am33xx.c b/arch/arm/mach-omap2/am33xx/clock_am33xx.c
index 1780bbd..9ab4d25 100644
--- a/arch/arm/mach-omap2/am33xx/clock_am33xx.c
+++ b/arch/arm/mach-omap2/am33xx/clock_am33xx.c
@@ -52,6 +52,13 @@ const struct dpll_regs dpll_ddr_regs = {
 	.cm_div_m2_dpll		= CM_WKUP + 0xA0,
 };
 
+const struct dpll_regs dpll_disp_regs = {
+	.cm_clkmode_dpll	= CM_WKUP + 0x98,
+	.cm_idlest_dpll		= CM_WKUP + 0x48,
+	.cm_clksel_dpll		= CM_WKUP + 0x54,
+	.cm_div_m2_dpll		= CM_WKUP + 0xA4,
+};
+
 struct dpll_params dpll_mpu_opp100 = {
 		CONFIG_SYS_MPUCLK, OSC-1, 1, -1, -1, -1, -1};
 const struct dpll_params dpll_core_opp100 = {
-- 
2.7.4

[U-Boot] [PATCH 1/6] mach-omap2: add AM335x Display PLL register definition

[Anatolij Gustschin]

On Tue,  9 Jan 2018 07:58:42 +0100
Hannes Schmelzer oe5hpm at oevsv.at wrote:

> Adds the register definition of the Display DPLL
> 
> Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>

Reviewed-by: Anatolij Gustschin <agust@denx.de>

[U-Boot] [PATCH 2/6] am335x-fb: cosmetic: update-copyright

[Hannes Schmelzer]

Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>
---

 drivers/video/am335x-fb.c | 4 ++--
 drivers/video/am335x-fb.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/video/am335x-fb.c b/drivers/video/am335x-fb.c
index a8b3e74..8cdd2ec 100644
--- a/drivers/video/am335x-fb.c
+++ b/drivers/video/am335x-fb.c
@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2013 Hannes Schmelzer <oe5hpm@oevsv.at>
- * Bernecker & Rainer Industrieelektronik GmbH - http://www.br-automation.com
+ * Copyright (C) 2018 Hannes Schmelzer <oe5hpm@oevsv.at>
+ * B&R Industrial Automation GmbH - http://www.br-automation.com
  *
  * minimal framebuffer driver for TI's AM335x SoC to be compatible with
  * Wolfgang Denk's LCD-Framework (CONFIG_LCD, common/lcd.c)
diff --git a/drivers/video/am335x-fb.h b/drivers/video/am335x-fb.h
index 3f4b567..1980eda 100644
--- a/drivers/video/am335x-fb.h
+++ b/drivers/video/am335x-fb.h
@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2013 Hannes Schmelzer <oe5hpm@oevsv.at> -
- * Bernecker & Rainer Industrieelektronik GmbH - http://www.br-automation.com
+ * Copyright (C) 2018 Hannes Schmelzer <oe5hpm@oevsv.at> -
+ * B&R Industrial Automation GmbH - http://www.br-automation.com
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */
-- 
2.7.4

[U-Boot] [PATCH 2/6] am335x-fb: cosmetic: update-copyright

[Anatolij Gustschin]

On Tue,  9 Jan 2018 07:58:43 +0100
Hannes Schmelzer oe5hpm at oevsv.at wrote:

> Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>

Reviewed-by: Anatolij Gustschin <agust@denx.de>

[U-Boot] [PATCH 3/6] am335x-fb: cosmetic: fix coding style

[Hannes Schmelzer]

Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>
---

 drivers/video/am335x-fb.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/video/am335x-fb.c b/drivers/video/am335x-fb.c
index 8cdd2ec..5494c3c 100644
--- a/drivers/video/am335x-fb.c
+++ b/drivers/video/am335x-fb.c
@@ -108,11 +108,11 @@ int am335xfb_init(struct am335x_lcdpanel *panel)
 {
 	u32 raster_ctrl = 0;
 
-	if (0 == gd->fb_base) {
+	if (gd->fb_base == NULL) {
 		printf("ERROR: no valid fb_base stored in GLOBAL_DATA_PTR!\n");
 		return -1;
 	}
-	if (0 == panel) {
+	if (panel == NULL) {
 		printf("ERROR: missing ptr to am335x_lcdpanel!\n");
 		return -1;
 	}
@@ -147,7 +147,7 @@ int am335xfb_init(struct am335x_lcdpanel *panel)
 	gd->fb_base += 0x20;
 
 	/* turn ON display through powercontrol function if accessible */
-	if (0 != panel->panel_power_ctrl)
+	if (panel->panel_power_ctrl != NULL)
 		panel->panel_power_ctrl(1);
 
 	debug("am335x-fb: wait for stable power ...\n");
-- 
2.7.4

[U-Boot] [PATCH 3/6] am335x-fb: cosmetic: fix coding style

[Anatolij Gustschin]

On Tue,  9 Jan 2018 07:58:44 +0100
Hannes Schmelzer oe5hpm at oevsv.at wrote:

> Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>

Reviewed-by: Anatolij Gustschin <agust@denx.de>

[U-Boot] [PATCH 4/6] am335x-fb: setup display PLL

[Hannes Schmelzer]

The LCDC IP-core an be feed from several clock sources, one of those is
a dedicated DPLL for generating a dividable base-clock for this IP-core.

The TRM specifies the maximum input frequency for the LCCD with 200 MHz,
so we must not exceed this value with the PLL frequency (which can lock
much higher).

This patch tries every combination of multipliers and divisors of the
PLL and the IP-core itself for getting as near as possible the the
requested panel->pxl_clk.

Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>
---

 drivers/video/am335x-fb.c | 54 ++++++++++++++++++++++++++++++++++++++++++++---
 drivers/video/am335x-fb.h |  2 +-
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/drivers/video/am335x-fb.c b/drivers/video/am335x-fb.c
index 5494c3c..1be28e3 100644
--- a/drivers/video/am335x-fb.c
+++ b/drivers/video/am335x-fb.c
@@ -12,7 +12,11 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 #include <common.h>
+#include <asm/io.h>
 #include <asm/arch/hardware.h>
+#include <asm/arch/omap.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/sys_proto.h>
 #include <lcd.h>
 #include "am335x-fb.h"
 
@@ -20,6 +24,7 @@
 #error "hw-base address of LCD-Controller (LCD_CNTL_BASE) not defined!"
 #endif
 
+#define LCDC_FMAX				200000000
 
 /* LCD Control Register */
 #define LCD_CLK_DIVISOR(x)			((x) << 8)
@@ -96,6 +101,7 @@ struct am335x_lcdhw {
 };
 
 static struct am335x_lcdhw *lcdhw = (void *)LCD_CNTL_BASE;
+
 DECLARE_GLOBAL_DATA_PTR;
 
 int lcd_get_size(int *line_length)
@@ -108,6 +114,11 @@ int am335xfb_init(struct am335x_lcdpanel *panel)
 {
 	u32 raster_ctrl = 0;
 
+	struct cm_dpll *const cmdpll = (struct cm_dpll *)CM_DPLL;
+	struct dpll_params dpll_disp = { 1, 0, 1, -1, -1, -1, -1 };
+	unsigned int m, n, d, best_d = 2;
+	int err = 0, err_r = 0;
+
 	if (gd->fb_base == NULL) {
 		printf("ERROR: no valid fb_base stored in GLOBAL_DATA_PTR!\n");
 		return -1;
@@ -132,14 +143,51 @@ int am335xfb_init(struct am335x_lcdpanel *panel)
 		return -1;
 	}
 
+	/* check given clock-frequency */
+	if (panel->pxl_clk > (LCDC_FMAX / 2)) {
+		pr_err("am335x-fb: requested pxl-clk: %d not supported!\n",
+		       panel->pxl_clk);
+		return -1;
+	}
+
 	debug("setting up LCD-Controller for %dx%dx%d (hfp=%d,hbp=%d,hsw=%d / ",
 	      panel->hactive, panel->vactive, panel->bpp,
 	      panel->hfp, panel->hbp, panel->hsw);
-	debug("vfp=%d,vbp=%d,vsw=%d / clk-div=%d)\n",
-	      panel->vfp, panel->vfp, panel->vsw, panel->pxl_clk_div);
+	debug("vfp=%d,vbp=%d,vsw=%d / clk=%d)\n",
+	      panel->vfp, panel->vfp, panel->vsw, panel->pxl_clk);
 	debug("using frambuffer at 0x%08x with size %d.\n",
 	      (unsigned int)gd->fb_base, FBSIZE(panel));
 
+	/* setup display pll for requested clock frequency */
+	err = panel->pxl_clk;
+	err_r = err;
+
+	for (d = 2; d < 255; d++) {
+		for (m = 2; m < 2047; m++) {
+			if ((V_OSCK * m) < (panel->pxl_clk * d))
+				continue;
+			n = (V_OSCK * m) / (panel->pxl_clk * d);
+			if (n > 127)
+				break;
+			if (((V_OSCK * m) / n) > LCDC_FMAX)
+				break;
+
+			err = abs((V_OSCK * m) / n / d - panel->pxl_clk);
+			if (err < err_r) {
+				err_r = err;
+				dpll_disp.m = m;
+				dpll_disp.n = n;
+				best_d = d;
+			}
+		}
+	}
+	debug("%s: PLL: best error %d Hz (M %d, N %d, DISP %d)\n",
+	      __func__, err_r, dpll_disp.m, dpll_disp.n, best_d);
+	do_setup_dpll(&dpll_disp_regs, &dpll_disp);
+
+	/* clock source for LCDC from dispPLL M2 */
+	writel(0x0, &cmdpll->clklcdcpixelclk);
+
 	/* palette default entry */
 	memset((void *)gd->fb_base, 0, 0x20);
 	*(unsigned int *)gd->fb_base = 0x4000;
@@ -154,7 +202,7 @@ int am335xfb_init(struct am335x_lcdpanel *panel)
 	mdelay(panel->pup_delay);
 	lcdhw->clkc_enable = LCD_CORECLKEN | LCD_LIDDCLKEN | LCD_DMACLKEN;
 	lcdhw->raster_ctrl = 0;
-	lcdhw->ctrl = LCD_CLK_DIVISOR(panel->pxl_clk_div) | LCD_RASTER_MODE;
+	lcdhw->ctrl = LCD_CLK_DIVISOR(best_d) | LCD_RASTER_MODE;
 	lcdhw->lcddma_fb0_base = gd->fb_base;
 	lcdhw->lcddma_fb0_ceiling = gd->fb_base + FBSIZE(panel);
 	lcdhw->lcddma_fb1_base = gd->fb_base;
diff --git a/drivers/video/am335x-fb.h b/drivers/video/am335x-fb.h
index 1980eda..e25c361 100644
--- a/drivers/video/am335x-fb.h
+++ b/drivers/video/am335x-fb.h
@@ -53,7 +53,7 @@ struct am335x_lcdpanel {
 	unsigned int	vfp;		/* Vertical front porch */
 	unsigned int	vbp;		/* Vertical back porch */
 	unsigned int	vsw;		/* Vertical Sync Pulse Width */
-	unsigned int	pxl_clk_div;	/* Pixel clock divider*/
+	unsigned int	pxl_clk;	/* Pixel clock */
 	unsigned int	pol;		/* polarity of sync, clock signals */
 	unsigned int	pup_delay;	/*
 					 * time in ms after power on to
-- 
2.7.4

[U-Boot] [PATCH 5/6] board/BuR: provide real clock-frequency instead a divider

[Hannes Schmelzer]

Actual am335x-fb implementation takes now a real clock frequency instead
a divider. So this component doesn't need to know anymore some base
frequency of the LCDC, we simply provide the pixel-clock frequency.

Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>
---

 board/BuR/common/common.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/board/BuR/common/common.c b/board/BuR/common/common.c
index 7e49cdf..0c64bed 100644
--- a/board/BuR/common/common.c
+++ b/board/BuR/common/common.c
@@ -146,13 +146,7 @@ int load_lcdtiming(struct am335x_lcdpanel *panel)
 	pnltmp.vsw = FDTPROP(PATHTIM, "vsync-len");
 	pnltmp.pup_delay = FDTPROP(PATHTIM, "pupdelay");
 	pnltmp.pon_delay = FDTPROP(PATHTIM, "pondelay");
-
-	/* calc. proper clk-divisor */
-	dtbprop = FDTPROP(PATHTIM, "clock-frequency");
-	if (dtbprop != ~0UL)
-		pnltmp.pxl_clk_div = 192000000 / dtbprop;
-	else
-		pnltmp.pxl_clk_div = ~0UL;
+	pnltmp.pxl_clk_div = FDTPROP(PATHTIM, "clock-frequency");
 
 	/* check polarity of control-signals */
 	dtbprop = FDTPROP(PATHTIM, "hsync-active");
@@ -202,7 +196,7 @@ int load_lcdtiming(struct am335x_lcdpanel *panel)
 	pnltmp.vfp = env_get_ulong("ds1_vfp", 10, ~0UL);
 	pnltmp.vbp = env_get_ulong("ds1_vbp", 10, ~0UL);
 	pnltmp.vsw = env_get_ulong("ds1_vsw", 10, ~0UL);
-	pnltmp.pxl_clk_div = env_get_ulong("ds1_pxlclkdiv", 10, ~0UL);
+	pnltmp.pxl_clk = env_get_ulong("ds1_pxlclk", 10, ~0UL);
 	pnltmp.pol = env_get_ulong("ds1_pol", 16, ~0UL);
 	pnltmp.pup_delay = env_get_ulong("ds1_pupdelay", 10, ~0UL);
 	pnltmp.pon_delay = env_get_ulong("ds1_tondelay", 10, ~0UL);
@@ -218,7 +212,7 @@ int load_lcdtiming(struct am335x_lcdpanel *panel)
 	   ~0UL == (pnltmp.vfp) ||
 	   ~0UL == (pnltmp.vbp) ||
 	   ~0UL == (pnltmp.vsw) ||
-	   ~0UL == (pnltmp.pxl_clk_div) ||
+	   ~0UL == (pnltmp.pxl_clk) ||
 	   ~0UL == (pnltmp.pol) ||
 	   ~0UL == (pnltmp.pup_delay) ||
 	   ~0UL == (pnltmp.pon_delay)
@@ -241,7 +235,7 @@ int load_lcdtiming(struct am335x_lcdpanel *panel)
 			pnltmp.hactive, pnltmp.vactive, pnltmp.bpp,
 			pnltmp.hfp, pnltmp.hbp, pnltmp.hsw,
 			pnltmp.vfp, pnltmp.vbp, pnltmp.vsw,
-			pnltmp.pxl_clk_div, pnltmp.pol, pnltmp.pon_delay);
+			pnltmp.pxl_clk, pnltmp.pol, pnltmp.pon_delay);
 
 		return -1;
 	}
-- 
2.7.4

[U-Boot] [PATCH 5/6] board/BuR: provide real clock-frequency instead a divider

[Anatolij Gustschin]

Hi Hannes,

On Tue,  9 Jan 2018 07:58:46 +0100
Hannes Schmelzer oe5hpm at oevsv.at wrote:
...
> -	dtbprop = FDTPROP(PATHTIM, "clock-frequency");
> -	if (dtbprop != ~0UL)
> -		pnltmp.pxl_clk_div = 192000000 / dtbprop;
> -	else
> -		pnltmp.pxl_clk_div = ~0UL;
> +	pnltmp.pxl_clk_div = FDTPROP(PATHTIM, "clock-frequency");

did you test !CONFIG_USE_FDT case? This should be

    pnltmp.pxl_clk = FDTPROP(PATHTIM, "clock-frequency");


--
Anatolij

[U-Boot] [PATCH 5/6] board/BuR: provide real clock-frequency instead a divider

[Hannes Schmelzer]

Am 09.01.2018 um 09:28 schrieb Anatolij Gustschin:
> Hi Hannes,
Hi Anatoli,
>
> On Tue,  9 Jan 2018 07:58:46 +0100
> Hannes Schmelzer oe5hpm at oevsv.at wrote:
> ...
>> -	dtbprop = FDTPROP(PATHTIM, "clock-frequency");
>> -	if (dtbprop != ~0UL)
>> -		pnltmp.pxl_clk_div = 192000000 / dtbprop;
>> -	else
>> -		pnltmp.pxl_clk_div = ~0UL;
>> +	pnltmp.pxl_clk_div = FDTPROP(PATHTIM, "clock-frequency");
> did you test !CONFIG_USE_FDT case? This should be
>
>      pnltmp.pxl_clk = FDTPROP(PATHTIM, "clock-frequency");
Thanks for catching this,  i've missed that.
Will prepare some V2 of the patch, sending it in the evening maybe some 
other improvements come up.
> --
> Anatolij
cheers,
Hannes

[U-Boot] [PATCH 6/6] board/BuR: drop LCDC clock manipulation from board code

[Hannes Schmelzer]

The clock selection is done now from the am335x-fb code, so there is no
more need doing this in the board code.

Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>
---

 board/BuR/brppt1/board.c | 3 ---
 board/BuR/brxre1/board.c | 2 --
 2 files changed, 5 deletions(-)

diff --git a/board/BuR/brppt1/board.c b/board/BuR/brppt1/board.c
index 6083479..9f7b2d9 100644
--- a/board/BuR/brppt1/board.c
+++ b/board/BuR/brppt1/board.c
@@ -120,9 +120,6 @@ void am33xx_spl_board_init(void)
 	};
 	do_enable_clocks(clk_domains, clk_modules_tsspecific, 1);
 
-	/* setup LCD-Pixel Clock */
-	writel(0x2, &cmdpll->clklcdcpixelclk);	/* clock comes from perPLL M2 */
-
 	/* setup I2C */
 	enable_i2c_pin_mux();
 	i2c_set_bus_num(0);
diff --git a/board/BuR/brxre1/board.c b/board/BuR/brxre1/board.c
index 856ac3d..e176b60 100644
--- a/board/BuR/brxre1/board.c
+++ b/board/BuR/brxre1/board.c
@@ -121,8 +121,6 @@ void am33xx_spl_board_init(void)
 		0
 	};
 	do_enable_clocks(clk_domains, clk_modules_xre1specific, 1);
-	/* setup LCD-Pixel Clock */
-	writel(0x2, CM_DPLL + 0x34);
 	/* power-OFF LCD-Display */
 	gpio_direction_output(LCD_PWR, 0);
 
-- 
2.7.4

[U-Boot] [PATCH 6/6] board/BuR: drop LCDC clock manipulation from board code

[Anatolij Gustschin]

On Tue,  9 Jan 2018 07:58:47 +0100
Hannes Schmelzer oe5hpm at oevsv.at wrote:

> The clock selection is done now from the am335x-fb code, so there is no
> more need doing this in the board code.
> 
> Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>

Reviewed-by: Anatolij Gustschin <agust@denx.de>