clk: ingenic: Allow divider value to be divided

The JZ4780's MSC clock divider registers multiply the clock divider by 2.
This means that MMC devices run at half their expected speed. Add the
ability to divide the clock divider in order to solve this.

Signed-off-by: Harvey Hunt <[e-mail]>
Cc: Paul Burton <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/ingenic/cgu.c

···
 		div = (div_reg >> clk_info->div.shift) &
 		      GENMASK(clk_info->div.bits - 1, 0);
 		div += 1;
+		div *= clk_info->div.div;
 
 		rate /= div;
 	}
···
 	/* and impose hardware constraints */
 	div = min_t(unsigned, div, 1 << clk_info->div.bits);
 	div = max_t(unsigned, div, 1);
+
+	/*
+	 * If the divider value itself must be divided before being written to
+	 * the divider register, we must ensure we don't have any bits set that
+	 * would be lost as a result of doing so.
+	 */
+	div /= clk_info->div.div;
+	div *= clk_info->div.div;
 
 	return div;
 }
···
 		/* update the divide */
 		mask = GENMASK(clk_info->div.bits - 1, 0);
 		reg &= ~(mask << clk_info->div.shift);
-		reg |= (div - 1) << clk_info->div.shift;
+		reg |= ((div / clk_info->div.div) - 1) << clk_info->div.shift;
 
 		/* clear the stop bit */
 		if (clk_info->div.stop_bit != -1)

drivers/clk/ingenic/cgu.h

···
 /**
  * struct ingenic_cgu_div_info - information about a divider
  * @reg: offset of the divider control register within the CGU
- * @shift: number of bits to shift the divide value by (ie. the index of
+ * @shift: number of bits to left shift the divide value by (ie. the index of
  *         the lowest bit of the divide value within its control register)
+ * @div: number of bits to divide the divider value by (i.e. if the
+ *	 effective divider value is the value written to the register
+ *	 multiplied by some constant)
  * @bits: the size of the divide value in bits
  * @ce_bit: the index of the change enable bit within reg, or -1 if there
  *          isn't one
···
 struct ingenic_cgu_div_info {
 	unsigned reg;
 	u8 shift;
+	u8 div;
 	u8 bits;
 	s8 ce_bit;
 	s8 busy_bit;

drivers/clk/ingenic/jz4740-cgu.c

···
 	[JZ4740_CLK_PLL_HALF] = {
 		"pll half", CGU_CLK_DIV,
 		.parents = { JZ4740_CLK_PLL, -1, -1, -1 },
-		.div = { CGU_REG_CPCCR, 21, 1, -1, -1, -1 },
+		.div = { CGU_REG_CPCCR, 21, 1, 1, -1, -1, -1 },
 	},
 
 	[JZ4740_CLK_CCLK] = {
 		"cclk", CGU_CLK_DIV,
 		.parents = { JZ4740_CLK_PLL, -1, -1, -1 },
-		.div = { CGU_REG_CPCCR, 0, 4, 22, -1, -1 },
+		.div = { CGU_REG_CPCCR, 0, 1, 4, 22, -1, -1 },
 	},
 
 	[JZ4740_CLK_HCLK] = {
 		"hclk", CGU_CLK_DIV,
 		.parents = { JZ4740_CLK_PLL, -1, -1, -1 },
-		.div = { CGU_REG_CPCCR, 4, 4, 22, -1, -1 },
+		.div = { CGU_REG_CPCCR, 4, 1, 4, 22, -1, -1 },
 	},
 
 	[JZ4740_CLK_PCLK] = {
 		"pclk", CGU_CLK_DIV,
 		.parents = { JZ4740_CLK_PLL, -1, -1, -1 },
-		.div = { CGU_REG_CPCCR, 8, 4, 22, -1, -1 },
+		.div = { CGU_REG_CPCCR, 8, 1, 4, 22, -1, -1 },
 	},
 
 	[JZ4740_CLK_MCLK] = {
 		"mclk", CGU_CLK_DIV,
 		.parents = { JZ4740_CLK_PLL, -1, -1, -1 },
-		.div = { CGU_REG_CPCCR, 12, 4, 22, -1, -1 },
+		.div = { CGU_REG_CPCCR, 12, 1, 4, 22, -1, -1 },
 	},
 
 	[JZ4740_CLK_LCD] = {
 		"lcd", CGU_CLK_DIV | CGU_CLK_GATE,
 		.parents = { JZ4740_CLK_PLL_HALF, -1, -1, -1 },
-		.div = { CGU_REG_CPCCR, 16, 5, 22, -1, -1 },
+		.div = { CGU_REG_CPCCR, 16, 1, 5, 22, -1, -1 },
 		.gate = { CGU_REG_CLKGR, 10 },
 	},
 
 	[JZ4740_CLK_LCD_PCLK] = {
 		"lcd_pclk", CGU_CLK_DIV,
 		.parents = { JZ4740_CLK_PLL_HALF, -1, -1, -1 },
-		.div = { CGU_REG_LPCDR, 0, 11, -1, -1, -1 },
+		.div = { CGU_REG_LPCDR, 0, 1, 11, -1, -1, -1 },
 	},
 
 	[JZ4740_CLK_I2S] = {
 		"i2s", CGU_CLK_MUX | CGU_CLK_DIV | CGU_CLK_GATE,
 		.parents = { JZ4740_CLK_EXT, JZ4740_CLK_PLL_HALF, -1, -1 },
 		.mux = { CGU_REG_CPCCR, 31, 1 },
-		.div = { CGU_REG_I2SCDR, 0, 8, -1, -1, -1 },
+		.div = { CGU_REG_I2SCDR, 0, 1, 8, -1, -1, -1 },
 		.gate = { CGU_REG_CLKGR, 6 },
 	},
 
···
 		"spi", CGU_CLK_MUX | CGU_CLK_DIV | CGU_CLK_GATE,
 		.parents = { JZ4740_CLK_EXT, JZ4740_CLK_PLL, -1, -1 },
 		.mux = { CGU_REG_SSICDR, 31, 1 },
-		.div = { CGU_REG_SSICDR, 0, 4, -1, -1, -1 },
+		.div = { CGU_REG_SSICDR, 0, 1, 4, -1, -1, -1 },
 		.gate = { CGU_REG_CLKGR, 4 },
 	},
 
 	[JZ4740_CLK_MMC] = {
 		"mmc", CGU_CLK_DIV | CGU_CLK_GATE,
 		.parents = { JZ4740_CLK_PLL_HALF, -1, -1, -1 },
-		.div = { CGU_REG_MSCCDR, 0, 5, -1, -1, -1 },
+		.div = { CGU_REG_MSCCDR, 0, 1, 5, -1, -1, -1 },
 		.gate = { CGU_REG_CLKGR, 7 },
 	},
 
 	[JZ4740_CLK_UHC] = {
 		"uhc", CGU_CLK_DIV | CGU_CLK_GATE,
 		.parents = { JZ4740_CLK_PLL_HALF, -1, -1, -1 },
-		.div = { CGU_REG_UHCCDR, 0, 4, -1, -1, -1 },
+		.div = { CGU_REG_UHCCDR, 0, 1, 4, -1, -1, -1 },
 		.gate = { CGU_REG_CLKGR, 14 },
 	},
 
···
 		"udc", CGU_CLK_MUX | CGU_CLK_DIV,
 		.parents = { JZ4740_CLK_EXT, JZ4740_CLK_PLL_HALF, -1, -1 },
 		.mux = { CGU_REG_CPCCR, 29, 1 },
-		.div = { CGU_REG_CPCCR, 23, 6, -1, -1, -1 },
+		.div = { CGU_REG_CPCCR, 23, 1, 6, -1, -1, -1 },
 		.gate = { CGU_REG_SCR, 6 },
 	},
 

drivers/clk/ingenic/jz4780-cgu.c

···
 	[JZ4780_CLK_CPU] = {
 		"cpu", CGU_CLK_DIV,
 		.parents = { JZ4780_CLK_CPUMUX, -1, -1, -1 },
-		.div = { CGU_REG_CLOCKCONTROL, 0, 4, 22, -1, -1 },
+		.div = { CGU_REG_CLOCKCONTROL, 0, 1, 4, 22, -1, -1 },
 	},
 
 	[JZ4780_CLK_L2CACHE] = {
 		"l2cache", CGU_CLK_DIV,
 		.parents = { JZ4780_CLK_CPUMUX, -1, -1, -1 },
-		.div = { CGU_REG_CLOCKCONTROL, 4, 4, -1, -1, -1 },
+		.div = { CGU_REG_CLOCKCONTROL, 4, 1, 4, -1, -1, -1 },
 	},
 
 	[JZ4780_CLK_AHB0] = {
···
 		.parents = { -1, JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_EPLL },
 		.mux = { CGU_REG_CLOCKCONTROL, 26, 2 },
-		.div = { CGU_REG_CLOCKCONTROL, 8, 4, 21, -1, -1 },
+		.div = { CGU_REG_CLOCKCONTROL, 8, 1, 4, 21, -1, -1 },
 	},
 
 	[JZ4780_CLK_AHB2PMUX] = {
···
 	[JZ4780_CLK_AHB2] = {
 		"ahb2", CGU_CLK_DIV,
 		.parents = { JZ4780_CLK_AHB2PMUX, -1, -1, -1 },
-		.div = { CGU_REG_CLOCKCONTROL, 12, 4, 20, -1, -1 },
+		.div = { CGU_REG_CLOCKCONTROL, 12, 1, 4, 20, -1, -1 },
 	},
 
 	[JZ4780_CLK_PCLK] = {
 		"pclk", CGU_CLK_DIV,
 		.parents = { JZ4780_CLK_AHB2PMUX, -1, -1, -1 },
-		.div = { CGU_REG_CLOCKCONTROL, 16, 4, 20, -1, -1 },
+		.div = { CGU_REG_CLOCKCONTROL, 16, 1, 4, 20, -1, -1 },
 	},
 
 	[JZ4780_CLK_DDR] = {
 		"ddr", CGU_CLK_MUX | CGU_CLK_DIV,
 		.parents = { -1, JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL, -1 },
 		.mux = { CGU_REG_DDRCDR, 30, 2 },
-		.div = { CGU_REG_DDRCDR, 0, 4, 29, 28, 27 },
+		.div = { CGU_REG_DDRCDR, 0, 1, 4, 29, 28, 27 },
 	},
 
 	[JZ4780_CLK_VPU] = {
···
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_EPLL, -1 },
 		.mux = { CGU_REG_VPUCDR, 30, 2 },
-		.div = { CGU_REG_VPUCDR, 0, 4, 29, 28, 27 },
+		.div = { CGU_REG_VPUCDR, 0, 1, 4, 29, 28, 27 },
 		.gate = { CGU_REG_CLKGR1, 2 },
 	},
 
···
 		"i2s_pll", CGU_CLK_MUX | CGU_CLK_DIV,
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_EPLL, -1, -1 },
 		.mux = { CGU_REG_I2SCDR, 30, 1 },
-		.div = { CGU_REG_I2SCDR, 0, 8, 29, 28, 27 },
+		.div = { CGU_REG_I2SCDR, 0, 1, 8, 29, 28, 27 },
 	},
 
 	[JZ4780_CLK_I2S] = {
···
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_VPLL, -1 },
 		.mux = { CGU_REG_LP0CDR, 30, 2 },
-		.div = { CGU_REG_LP0CDR, 0, 8, 28, 27, 26 },
+		.div = { CGU_REG_LP0CDR, 0, 1, 8, 28, 27, 26 },
 	},
 
 	[JZ4780_CLK_LCD1PIXCLK] = {
···
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_VPLL, -1 },
 		.mux = { CGU_REG_LP1CDR, 30, 2 },
-		.div = { CGU_REG_LP1CDR, 0, 8, 28, 27, 26 },
+		.div = { CGU_REG_LP1CDR, 0, 1, 8, 28, 27, 26 },
 	},
 
 	[JZ4780_CLK_MSCMUX] = {
···
 	[JZ4780_CLK_MSC0] = {
 		"msc0", CGU_CLK_DIV | CGU_CLK_GATE,
 		.parents = { JZ4780_CLK_MSCMUX, -1, -1, -1 },
-		.div = { CGU_REG_MSC0CDR, 0, 8, 29, 28, 27 },
+		.div = { CGU_REG_MSC0CDR, 0, 2, 8, 29, 28, 27 },
 		.gate = { CGU_REG_CLKGR0, 3 },
 	},
 
 	[JZ4780_CLK_MSC1] = {
 		"msc1", CGU_CLK_DIV | CGU_CLK_GATE,
 		.parents = { JZ4780_CLK_MSCMUX, -1, -1, -1 },
-		.div = { CGU_REG_MSC1CDR, 0, 8, 29, 28, 27 },
+		.div = { CGU_REG_MSC1CDR, 0, 2, 8, 29, 28, 27 },
 		.gate = { CGU_REG_CLKGR0, 11 },
 	},
 
 	[JZ4780_CLK_MSC2] = {
 		"msc2", CGU_CLK_DIV | CGU_CLK_GATE,
 		.parents = { JZ4780_CLK_MSCMUX, -1, -1, -1 },
-		.div = { CGU_REG_MSC2CDR, 0, 8, 29, 28, 27 },
+		.div = { CGU_REG_MSC2CDR, 0, 2, 8, 29, 28, 27 },
 		.gate = { CGU_REG_CLKGR0, 12 },
 	},
 
···
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_EPLL, JZ4780_CLK_OTGPHY },
 		.mux = { CGU_REG_UHCCDR, 30, 2 },
-		.div = { CGU_REG_UHCCDR, 0, 8, 29, 28, 27 },
+		.div = { CGU_REG_UHCCDR, 0, 1, 8, 29, 28, 27 },
 		.gate = { CGU_REG_CLKGR0, 24 },
 	},
 
···
 		"ssi_pll", CGU_CLK_MUX | CGU_CLK_DIV,
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL, -1, -1 },
 		.mux = { CGU_REG_SSICDR, 30, 1 },
-		.div = { CGU_REG_SSICDR, 0, 8, 29, 28, 27 },
+		.div = { CGU_REG_SSICDR, 0, 1, 8, 29, 28, 27 },
 	},
 
 	[JZ4780_CLK_SSI] = {
···
 		"cim_mclk", CGU_CLK_MUX | CGU_CLK_DIV,
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL, -1, -1 },
 		.mux = { CGU_REG_CIMCDR, 31, 1 },
-		.div = { CGU_REG_CIMCDR, 0, 8, 30, 29, 28 },
+		.div = { CGU_REG_CIMCDR, 0, 1, 8, 30, 29, 28 },
 	},
 
 	[JZ4780_CLK_PCMPLL] = {
···
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_EPLL, JZ4780_CLK_VPLL },
 		.mux = { CGU_REG_PCMCDR, 29, 2 },
-		.div = { CGU_REG_PCMCDR, 0, 8, 28, 27, 26 },
+		.div = { CGU_REG_PCMCDR, 0, 1, 8, 28, 27, 26 },
 	},
 
 	[JZ4780_CLK_PCM] = {
···
 		.parents = { -1, JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_EPLL },
 		.mux = { CGU_REG_GPUCDR, 30, 2 },
-		.div = { CGU_REG_GPUCDR, 0, 4, 29, 28, 27 },
+		.div = { CGU_REG_GPUCDR, 0, 1, 4, 29, 28, 27 },
 		.gate = { CGU_REG_CLKGR1, 4 },
 	},
 
···
 		.parents = { JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_VPLL, -1 },
 		.mux = { CGU_REG_HDMICDR, 30, 2 },
-		.div = { CGU_REG_HDMICDR, 0, 8, 29, 28, 26 },
+		.div = { CGU_REG_HDMICDR, 0, 1, 8, 29, 28, 26 },
 		.gate = { CGU_REG_CLKGR1, 9 },
 	},
 
···
 		.parents = { -1, JZ4780_CLK_SCLKA, JZ4780_CLK_MPLL,
 			     JZ4780_CLK_EPLL },
 		.mux = { CGU_REG_BCHCDR, 30, 2 },
-		.div = { CGU_REG_BCHCDR, 0, 4, 29, 28, 27 },
+		.div = { CGU_REG_BCHCDR, 0, 1, 4, 29, 28, 27 },
 		.gate = { CGU_REG_CLKGR0, 1 },
 	},