Re: [PATCHv9 1/4] clk: socfpga: Add a clk-phase property to the "altr, socfpga-gate-clk"

[Jaehoon Chung <jh80.chung@samsung.com>]

Acked-by: Jaehoon Chung <jh80.chung@samsung.com>

On 01/10/2014 06:31 AM, dinguyen@altera.com wrote:
> From: Dinh Nguyen <dinguyen@altera.com>
> 
> The clk-phase property is used to represent the 2 clock phase values that is
> needed for the SD/MMC driver. Add a prepare function to the clk_ops, that will
> use the syscon driver to set sdmmc_clk's phase shift that is located in the
> system manager.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
> Acked-by: Zhangfei Gao <zhangfei.gao@linaro.org>
> ---
> v9: none
> v8: Use degrees in the clk-phase binding property
> v7: Add dts property to represent the clk phase of the sdmmc_clk. Add a
>     prepare function to the gate clk that will toggle clock phase setting.
>     Remove the "altr,socfpga-sdmmc-sdr-clk" clock type.
> v6: Add a new clock type "altr,socfpga-sdmmc-sdr-clk" that will be used to
>     set the phase shift settings.
> v5: Use the "snps,dw-mshc" binding
> v4: Use the sdmmc_clk prepare function to set the phase shift settings
> v3: Not use the syscon driver because as of 3.13-rc1, the syscon driver is
>     loaded after the clock driver.
> v2: Use the syscon driver
> ---
>  .../devicetree/bindings/clock/altr_socfpga.txt     |    5 ++
>  arch/arm/boot/dts/socfpga.dtsi                     |    1 +
>  drivers/clk/socfpga/clk-gate.c                     |   68 ++++++++++++++++++++
>  3 files changed, 74 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/clock/altr_socfpga.txt b/Documentation/devicetree/bindings/clock/altr_socfpga.txt
> index 0045433..5dfd145 100644
> --- a/Documentation/devicetree/bindings/clock/altr_socfpga.txt
> +++ b/Documentation/devicetree/bindings/clock/altr_socfpga.txt
> @@ -23,3 +23,8 @@ Optional properties:
>          and the bit index.
>  - div-reg : For "socfpga-gate-clk", div-reg contains the divider register, bit shift,
>          and width.
> +- clk-phase : For the sdmmc_clk, contains the value of the clock phase that controls
> +	the SDMMC CIU clock. The first value is the clk_sample(smpsel), and the second
> +	value is the cclk_in_drv(drvsel). The clk-phase is used to enable the correct
> +	hold/delay times that is needed for the SD/MMC CIU clock. The values of both
> +	can be 0-315 degrees, in 45 degree increments.
> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
> index f936476..e776512 100644
> --- a/arch/arm/boot/dts/socfpga.dtsi
> +++ b/arch/arm/boot/dts/socfpga.dtsi
> @@ -413,6 +413,7 @@
>  						compatible = "altr,socfpga-gate-clk";
>  						clocks = <&f2s_periph_ref_clk>, <&main_nand_sdmmc_clk>, <&per_nand_mmc_clk>;
>  						clk-gate = <0xa0 8>;
> +						clk-phase = <0 135>;
>  					};
>  
>  					nand_x_clk: nand_x_clk {
> diff --git a/drivers/clk/socfpga/clk-gate.c b/drivers/clk/socfpga/clk-gate.c
> index 4efcf4e..501d513 100644
> --- a/drivers/clk/socfpga/clk-gate.c
> +++ b/drivers/clk/socfpga/clk-gate.c
> @@ -19,7 +19,9 @@
>  #include <linux/clkdev.h>
>  #include <linux/clk-provider.h>
>  #include <linux/io.h>
> +#include <linux/mfd/syscon.h>
>  #include <linux/of.h>
> +#include <linux/regmap.h>
>  
>  #include "clk.h"
>  
> @@ -35,6 +37,11 @@
>  
>  #define to_socfpga_gate_clk(p) container_of(p, struct socfpga_gate_clk, hw.hw)
>  
> +/* SDMMC Group for System Manager defines */
> +#define SYSMGR_SDMMCGRP_CTRL_OFFSET    0x108
> +#define SYSMGR_SDMMC_CTRL_SET(smplsel, drvsel) \
> +	((((smplsel) & 0x7) << 3) | (((drvsel) & 0x7) << 0))
> +
>  static u8 socfpga_clk_get_parent(struct clk_hw *hwclk)
>  {
>  	u32 l4_src;
> @@ -115,7 +122,61 @@ static unsigned long socfpga_clk_recalc_rate(struct clk_hw *hwclk,
>  	return parent_rate / div;
>  }
>  
> +static int socfpga_clk_prepare(struct clk_hw *hwclk)
> +{
> +	struct socfpga_gate_clk *socfpgaclk = to_socfpga_gate_clk(hwclk);
> +	struct regmap *sys_mgr_base_addr;
> +	int i;
> +	u32 hs_timing;
> +	u32 clk_phase[2];
> +
> +	if (socfpgaclk->clk_phase[0] || socfpgaclk->clk_phase[1]) {
> +		sys_mgr_base_addr = syscon_regmap_lookup_by_compatible("altr,sys-mgr");
> +		if (IS_ERR(sys_mgr_base_addr)) {
> +			pr_err("%s: failed to find altr,sys-mgr regmap!\n", __func__);
> +			return -EINVAL;
> +		}
> +
> +		for (i = 0; i < 2; i++) {
> +			switch (socfpgaclk->clk_phase[i]) {
> +			case 0:
> +				clk_phase[i] = 0;
> +				break;
> +			case 45:
> +				clk_phase[i] = 1;
> +				break;
> +			case 90:
> +				clk_phase[i] = 2;
> +				break;
> +			case 135:
> +				clk_phase[i] = 3;
> +				break;
> +			case 180:
> +				clk_phase[i] = 4;
> +				break;
> +			case 225:
> +				clk_phase[i] = 5;
> +				break;
> +			case 270:
> +				clk_phase[i] = 6;
> +				break;
> +			case 315:
> +				clk_phase[i] = 7;
> +				break;
> +			default:
> +				clk_phase[i] = 0;
> +				break;
> +			}
> +		}
> +		hs_timing = SYSMGR_SDMMC_CTRL_SET(clk_phase[0], clk_phase[1]);
> +		regmap_write(sys_mgr_base_addr, SYSMGR_SDMMCGRP_CTRL_OFFSET,
> +			hs_timing);
> +	}
> +	return 0;
> +}
> +
>  static struct clk_ops gateclk_ops = {
> +	.prepare = socfpga_clk_prepare,
>  	.recalc_rate = socfpga_clk_recalc_rate,
>  	.get_parent = socfpga_clk_get_parent,
>  	.set_parent = socfpga_clk_set_parent,
> @@ -126,6 +187,7 @@ static void __init __socfpga_gate_init(struct device_node *node,
>  {
>  	u32 clk_gate[2];
>  	u32 div_reg[3];
> +	u32 clk_phase[2];
>  	u32 fixed_div;
>  	struct clk *clk;
>  	struct socfpga_gate_clk *socfpga_clk;
> @@ -166,6 +228,12 @@ static void __init __socfpga_gate_init(struct device_node *node,
>  		socfpga_clk->div_reg = 0;
>  	}
>  
> +	rc = of_property_read_u32_array(node, "clk-phase", clk_phase, 2);
> +	if (!rc) {
> +		socfpga_clk->clk_phase[0] = clk_phase[0];
> +		socfpga_clk->clk_phase[1] = clk_phase[1];
> +	}
> +
>  	of_property_read_string(node, "clock-output-names", &clk_name);
>  
>  	init.name = clk_name;
>