[PATCH 1/2] clk: socfpga: add divider registers to the main pll outputs

[Dinh Nguyen]

On 04/16/2014 03:14 PM, dinguyen at altera.com wrote:
> From: Dinh Nguyen <dinguyen at altera.com>
>
> The C0(mpu_clk), C1(main_clk), and C2(dbg_base_clk) outputs from the main
> PLL go through a pre-divider before coming into the system. These registers
> were hidden for the CycloneV platform, but are not used for the ArriaV

Sorry but this should be "but are now used"

> platform.
>
> This patch updates the clock driver to read the div-reg property for the
> socfpga-periph-clk clocks. Also moves the div_mask define to clk.h for re-use.
>
> Signed-off-by: Dinh Nguyen <dinguyen at altera.com>
> ---
>   drivers/clk/socfpga/clk-gate.c   |    1 -
>   drivers/clk/socfpga/clk-periph.c |   22 +++++++++++++++++++---
>   drivers/clk/socfpga/clk.h        |    4 ++++
>   3 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/clk/socfpga/clk-gate.c b/drivers/clk/socfpga/clk-gate.c
> index 501d513..dd3a78c 100644
> --- a/drivers/clk/socfpga/clk-gate.c
> +++ b/drivers/clk/socfpga/clk-gate.c
> @@ -32,7 +32,6 @@
>   #define SOCFPGA_MMC_CLK			"sdmmc_clk"
>   #define SOCFPGA_GPIO_DB_CLK_OFFSET	0xA8
>
> -#define div_mask(width)	((1 << (width)) - 1)
>   #define streq(a, b) (strcmp((a), (b)) == 0)
>
>   #define to_socfpga_gate_clk(p) container_of(p, struct socfpga_gate_clk, hw.hw)
> diff --git a/drivers/clk/socfpga/clk-periph.c b/drivers/clk/socfpga/clk-periph.c
> index 81623a3..46531c3 100644
> --- a/drivers/clk/socfpga/clk-periph.c
> +++ b/drivers/clk/socfpga/clk-periph.c
> @@ -29,12 +29,18 @@ static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
>   					     unsigned long parent_rate)
>   {
>   	struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
> -	u32 div;
> +	u32 div, val;
>
> -	if (socfpgaclk->fixed_div)
> +	if (socfpgaclk->fixed_div) {
>   		div = socfpgaclk->fixed_div;
> -	else
> +	} else {
> +		if (socfpgaclk->div_reg) {
> +			val = readl(socfpgaclk->div_reg) >> socfpgaclk->shift;
> +			val &= div_mask(socfpgaclk->width);
> +			parent_rate /= (val + 1);
> +		}
>   		div = ((readl(socfpgaclk->hw.reg) & 0x1ff) + 1);
> +	}
>
>   	return parent_rate / div;
>   }
> @@ -54,6 +60,7 @@ static __init void __socfpga_periph_init(struct device_node *node,
>   	struct clk_init_data init;
>   	int rc;
>   	u32 fixed_div;
> +	u32 div_reg[3];
>
>   	of_property_read_u32(node, "reg", &reg);
>
> @@ -63,6 +70,15 @@ static __init void __socfpga_periph_init(struct device_node *node,
>
>   	periph_clk->hw.reg = clk_mgr_base_addr + reg;
>
> +	rc = of_property_read_u32_array(node, "div-reg", div_reg, 3);
> +	if (!rc) {
> +		periph_clk->div_reg = clk_mgr_base_addr + div_reg[0];
> +		periph_clk->shift = div_reg[1];
> +		periph_clk->width = div_reg[2];
> +	} else {
> +		periph_clk->div_reg = 0;
> +	}
> +
>   	rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
>   	if (rc)
>   		periph_clk->fixed_div = 0;
> diff --git a/drivers/clk/socfpga/clk.h b/drivers/clk/socfpga/clk.h
> index d2e5401..d291f60 100644
> --- a/drivers/clk/socfpga/clk.h
> +++ b/drivers/clk/socfpga/clk.h
> @@ -27,6 +27,7 @@
>   #define CLKMGR_PERPLL_SRC	0xAC
>
>   #define SOCFPGA_MAX_PARENTS		3
> +#define div_mask(width) ((1 << (width)) - 1)
>
>   extern void __iomem *clk_mgr_base_addr;
>
> @@ -52,6 +53,9 @@ struct socfpga_periph_clk {
>   	struct clk_gate hw;
>   	char *parent_name;
>   	u32 fixed_div;
> +	void __iomem *div_reg;
> +	u32 width;      /* only valid if div_reg != 0 */
> +	u32 shift;      /* only valid if div_reg != 0 */
>   };
>
>   #endif /* SOCFPGA_CLK_H */
>