OMAP4: DSS2: Clock source changes for OMAP4

On OMAP3, the pixel clock for the LCD manager was derived through DISPC_FCLK as:

Lcd Pixel clock = DISPC_FCLK / lcd / pcd

Where lcd and pcd are divisors in the DISPC_DIVISOR register.

On OMAP4, the pixel clocks for LCD1 and LCD2 managers are derived from 2 new
clocks named LCD1_CLK and LCD2_CLK. The pixel clocks are calculated as:

Lcd_o Pixel clock = LCDo_CLK / lcdo /pcdo, o = 1, 2

Where lcdo and pcdo registers are divisors in DISPC_DIVISORo registers.

LCD1_CLK and LCD2_CLK can have DSS_FCLK, and the M4 divider clocks of DSI1 PLL
and DSI2 PLL as clock sources respectively. Introduce functions to select and
get the clock source for these new clocks. Modify DISPC functions get the
correct lck and pck rates based on the clock source of these clocks. Since
OMAP2/3 don't have these clocks, force OMAP2/3 to always have the LCD_CLK source
as DSS_CLK_SRC_FCK by introducing a dss feature.

Introduce clock source names for OMAP4 and some register field changes in
DSS_CTRL on OMAP4.

Currently, LCD2_CLK can only have DSS_FCLK as its clock source as DSI2 PLL
functionality hasn't been introduced yet. BUG for now if DSI2 PLL is selected as
clock.

Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap2/dss/dispc.c

@@ -2365,25 +2365,33 @@ unsigned long dispc_lclk_rate(enum omap_channel channel)
 
 	lcd = FLD_GET(l, 23, 16);
 
-	r = dispc_fclk_rate();
+	switch (dss_get_lcd_clk_source(channel)) {
+	case DSS_CLK_SRC_FCK:
+		r = dss_clk_get_rate(DSS_CLK_FCK);
+		break;
+	case DSS_CLK_SRC_DSI_PLL_HSDIV_DISPC:
+		r = dsi_get_pll_hsdiv_dispc_rate();
+		break;
+	default:
+		BUG();
+	}
 
 	return r / lcd;
 }
 
 unsigned long dispc_pclk_rate(enum omap_channel channel)
 {
-	int lcd, pcd;
+	int pcd;
 	unsigned long r;
 	u32 l;
 
 	l = dispc_read_reg(DISPC_DIVISORo(channel));
 
-	lcd = FLD_GET(l, 23, 16);
 	pcd = FLD_GET(l, 7, 0);
 
-	r = dispc_fclk_rate();
+	r = dispc_lclk_rate(channel);
 
-	return r / lcd / pcd;
+	return r / pcd;
 }
 
 void dispc_dump_clocks(struct seq_file *s)
@@ -2391,6 +2399,7 @@ void dispc_dump_clocks(struct seq_file *s)
 	int lcd, pcd;
 	u32 l;
 	enum dss_clk_source dispc_clk_src = dss_get_dispc_clk_source();
+	enum dss_clk_source lcd_clk_src;
 
 	enable_clocks(1);
 
@@ -2412,6 +2421,12 @@ void dispc_dump_clocks(struct seq_file *s)
 	}
 	seq_printf(s, "- LCD1 -\n");
 
+	lcd_clk_src = dss_get_lcd_clk_source(OMAP_DSS_CHANNEL_LCD);
+
+	seq_printf(s, "lcd1_clk source = %s (%s)\n",
+		dss_get_generic_clk_source_name(lcd_clk_src),
+		dss_feat_get_clk_source_name(lcd_clk_src));
+
 	dispc_get_lcd_divisor(OMAP_DSS_CHANNEL_LCD, &lcd, &pcd);
 
 	seq_printf(s, "lck\t\t%-16lulck div\t%u\n",
@@ -2421,6 +2436,12 @@ void dispc_dump_clocks(struct seq_file *s)
 	if (dss_has_feature(FEAT_MGR_LCD2)) {
 		seq_printf(s, "- LCD2 -\n");
 
+		lcd_clk_src = dss_get_lcd_clk_source(OMAP_DSS_CHANNEL_LCD2);
+
+		seq_printf(s, "lcd2_clk source = %s (%s)\n",
+			dss_get_generic_clk_source_name(lcd_clk_src),
+			dss_feat_get_clk_source_name(lcd_clk_src));
+
 		dispc_get_lcd_divisor(OMAP_DSS_CHANNEL_LCD2, &lcd, &pcd);
 
 		seq_printf(s, "lck\t\t%-16lulck div\t%u\n",

drivers/video/omap2/dss/dss.c

@@ -77,6 +77,7 @@ static struct {
 
 	enum dss_clk_source dsi_clk_source;
 	enum dss_clk_source dispc_clk_source;
+	enum dss_clk_source lcd_clk_source[MAX_DSS_LCD_MANAGERS];
 
 	u32		ctx[DSS_SZ_REGS / sizeof(u32)];
 } dss;
@@ -292,6 +293,7 @@ void dss_dump_regs(struct seq_file *s)
 void dss_select_dispc_clk_source(enum dss_clk_source clk_src)
 {
 	int b;
+	u8 start, end;
 
 	switch (clk_src) {
 	case DSS_CLK_SRC_FCK:
@@ -305,7 +307,9 @@ void dss_select_dispc_clk_source(enum dss_clk_source clk_src)
 		BUG();
 	}
 
-	REG_FLD_MOD(DSS_CONTROL, b, 0, 0);	/* DISPC_CLK_SWITCH */
+	dss_feat_get_reg_field(FEAT_REG_DISPC_CLK_SWITCH, &start, &end);
+
+	REG_FLD_MOD(DSS_CONTROL, b, start, end);	/* DISPC_CLK_SWITCH */
 
 	dss.dispc_clk_source = clk_src;
 }
@@ -331,6 +335,34 @@ void dss_select_dsi_clk_source(enum dss_clk_source clk_src)
 	dss.dsi_clk_source = clk_src;
 }
 
+void dss_select_lcd_clk_source(enum omap_channel channel,
+		enum dss_clk_source clk_src)
+{
+	int b, ix, pos;
+
+	if (!dss_has_feature(FEAT_LCD_CLK_SRC))
+		return;
+
+	switch (clk_src) {
+	case DSS_CLK_SRC_FCK:
+		b = 0;
+		break;
+	case DSS_CLK_SRC_DSI_PLL_HSDIV_DISPC:
+		BUG_ON(channel != OMAP_DSS_CHANNEL_LCD);
+		b = 1;
+		dsi_wait_pll_hsdiv_dispc_active();
+		break;
+	default:
+		BUG();
+	}
+
+	pos = channel == OMAP_DSS_CHANNEL_LCD ? 0 : 12;
+	REG_FLD_MOD(DSS_CONTROL, b, pos, pos);	/* LCDx_CLK_SWITCH */
+
+	ix = channel == OMAP_DSS_CHANNEL_LCD ? 0 : 1;
+	dss.lcd_clk_source[ix] = clk_src;
+}
+
 enum dss_clk_source dss_get_dispc_clk_source(void)
 {
 	return dss.dispc_clk_source;
@@ -341,6 +373,12 @@ enum dss_clk_source dss_get_dsi_clk_source(void)
 	return dss.dsi_clk_source;
 }
 
+enum dss_clk_source dss_get_lcd_clk_source(enum omap_channel channel)
+{
+	int ix = channel == OMAP_DSS_CHANNEL_LCD ? 0 : 1;
+	return dss.lcd_clk_source[ix];
+}
+
 /* calculate clock rates using dividers in cinfo */
 int dss_calc_clock_rates(struct dss_clock_info *cinfo)
 {
@@ -624,6 +662,8 @@ static int dss_init(void)
 
 	dss.dsi_clk_source = DSS_CLK_SRC_FCK;
 	dss.dispc_clk_source = DSS_CLK_SRC_FCK;
+	dss.lcd_clk_source[0] = DSS_CLK_SRC_FCK;
+	dss.lcd_clk_source[1] = DSS_CLK_SRC_FCK;
 
 	dss_save_context();
 

drivers/video/omap2/dss/dss.h

@@ -118,9 +118,12 @@ enum dss_clock {
 };
 
 enum dss_clk_source {
-	DSS_CLK_SRC_DSI_PLL_HSDIV_DISPC,	/* DSI1_PLL_FCLK */
-	DSS_CLK_SRC_DSI_PLL_HSDIV_DSI,		/* DSI2_PLL_FCLK */
-	DSS_CLK_SRC_FCK,			/* DSS1_ALWON_FCLK */
+	DSS_CLK_SRC_DSI_PLL_HSDIV_DISPC,	/* OMAP3: DSI1_PLL_FCLK
+						 * OMAP4: PLL1_CLK1 */
+	DSS_CLK_SRC_DSI_PLL_HSDIV_DSI,		/* OMAP3: DSI2_PLL_FCLK
+						 * OMAP4: PLL1_CLK2 */
+	DSS_CLK_SRC_FCK,			/* OMAP2/3: DSS1_ALWON_FCLK
+						 * OMAP4: DSS_FCLK */
 };
 
 /* Correlates clock source name and dss_clk_source member */
@@ -152,17 +155,19 @@ struct dsi_clock_info {
 	unsigned long fint;
 	unsigned long clkin4ddr;
 	unsigned long clkin;
-	unsigned long dsi_pll_hsdiv_dispc_clk;	/* DSI1_PLL_CLK */
-	unsigned long dsi_pll_hsdiv_dsi_clk;	/* DSI2_PLL_CLK */
-
+	unsigned long dsi_pll_hsdiv_dispc_clk;	/* OMAP3: DSI1_PLL_CLK
+						 * OMAP4: PLLx_CLK1 */
+	unsigned long dsi_pll_hsdiv_dsi_clk;	/* OMAP3: DSI2_PLL_CLK
+						 * OMAP4: PLLx_CLK2 */
 	unsigned long lp_clk;
 
 	/* dividers */
 	u16 regn;
 	u16 regm;
-	u16 regm_dispc;	/* REGM3 */
-	u16 regm_dsi;	/* REGM4 */
-
+	u16 regm_dispc;	/* OMAP3: REGM3
+			 * OMAP4: REGM4 */
+	u16 regm_dsi;	/* OMAP3: REGM4
+			 * OMAP4: REGM5 */
 	u16 lp_clk_div;
 
 	u8 highfreq;
@@ -235,8 +240,11 @@ void dss_sdi_disable(void);
 
 void dss_select_dispc_clk_source(enum dss_clk_source clk_src);
 void dss_select_dsi_clk_source(enum dss_clk_source clk_src);
+void dss_select_lcd_clk_source(enum omap_channel channel,
+		enum dss_clk_source clk_src);
 enum dss_clk_source dss_get_dispc_clk_source(void);
 enum dss_clk_source dss_get_dsi_clk_source(void);
+enum dss_clk_source dss_get_lcd_clk_source(enum omap_channel channel);
 
 void dss_set_venc_output(enum omap_dss_venc_type type);
 void dss_set_dac_pwrdn_bgz(bool enable);

drivers/video/omap2/dss/dss_features.c

@@ -59,6 +59,7 @@ static const struct dss_reg_field omap2_dss_reg_fields[] = {
 	{ FEAT_REG_FIFOSIZE, 8, 0 },
 	{ FEAT_REG_HORIZONTALACCU, 9, 0 },
 	{ FEAT_REG_VERTICALACCU, 25, 16 },
+	{ FEAT_REG_DISPC_CLK_SWITCH, 0, 0 },
 };
 
 static const struct dss_reg_field omap3_dss_reg_fields[] = {
@@ -69,6 +70,7 @@ static const struct dss_reg_field omap3_dss_reg_fields[] = {
 	{ FEAT_REG_FIFOSIZE, 10, 0 },
 	{ FEAT_REG_HORIZONTALACCU, 9, 0 },
 	{ FEAT_REG_VERTICALACCU, 25, 16 },
+	{ FEAT_REG_DISPC_CLK_SWITCH, 0, 0 },
 };
 
 static const struct dss_reg_field omap4_dss_reg_fields[] = {
@@ -79,6 +81,7 @@ static const struct dss_reg_field omap4_dss_reg_fields[] = {
 	{ FEAT_REG_FIFOSIZE, 15, 0 },
 	{ FEAT_REG_HORIZONTALACCU, 10, 0 },
 	{ FEAT_REG_VERTICALACCU, 26, 16 },
+	{ FEAT_REG_DISPC_CLK_SWITCH, 9, 8 },
 };
 
 static const enum omap_display_type omap2_dss_supported_displays[] = {
@@ -171,6 +174,12 @@ static const struct dss_clk_source_name omap3_dss_clk_source_names[] = {
 	{ DSS_CLK_SRC_FCK, "DSS1_ALWON_FCLK" },
 };
 
+static const struct dss_clk_source_name omap4_dss_clk_source_names[] = {
+	{ DSS_CLK_SRC_DSI_PLL_HSDIV_DISPC, "PLL1_CLK1" },
+	{ DSS_CLK_SRC_DSI_PLL_HSDIV_DSI, "PLL1_CLK2" },
+	{ DSS_CLK_SRC_FCK, "DSS_FCLK" },
+};
+
 /* OMAP2 DSS Features */
 static struct omap_dss_features omap2_dss_features = {
 	.reg_fields = omap2_dss_reg_fields,
@@ -235,14 +244,14 @@ static struct omap_dss_features omap4_dss_features = {
 	.has_feature	=
 		FEAT_GLOBAL_ALPHA | FEAT_PRE_MULT_ALPHA |
 		FEAT_MGR_LCD2 | FEAT_GLOBAL_ALPHA_VID1 |
-		FEAT_CORE_CLK_DIV,
+		FEAT_CORE_CLK_DIV | FEAT_LCD_CLK_SRC,
 
 	.num_mgrs = 3,
 	.num_ovls = 3,
 	.max_dss_fck = 186000000,
 	.supported_displays = omap4_dss_supported_displays,
 	.supported_color_modes = omap3_dss_supported_color_modes,
-	.clksrc_names = omap3_dss_clk_source_names,
+	.clksrc_names = omap4_dss_clk_source_names,
 };
 
 /* Functions returning values related to a DSS feature */

drivers/video/omap2/dss/dss_features.h

@@ -22,6 +22,7 @@
 
 #define MAX_DSS_MANAGERS	3
 #define MAX_DSS_OVERLAYS	3
+#define MAX_DSS_LCD_MANAGERS	2
 
 /* DSS has feature id */
 enum dss_feat_id {
@@ -38,6 +39,7 @@ enum dss_feat_id {
 	FEAT_RESIZECONF		= 1 << 10,
 	/* Independent core clk divider */
 	FEAT_CORE_CLK_DIV	= 1 << 11,
+	FEAT_LCD_CLK_SRC	= 1 << 12,
 };
 
 /* DSS register field id */
@@ -49,6 +51,7 @@ enum dss_feat_reg_field {
 	FEAT_REG_FIFOSIZE,
 	FEAT_REG_HORIZONTALACCU,
 	FEAT_REG_VERTICALACCU,
+	FEAT_REG_DISPC_CLK_SWITCH,
 };
 
 /* DSS Feature Functions */