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>

1 files changed, 41 insertions, 1 deletions

diff --git a/drivers/video/omap2/dss/dss.c b/drivers/video/omap2/dss/dss.c
index 93813fd626be..aed9345e8ada 100644
--- a/drivers/video/omap2/dss/dss.c
+++ b/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();