diff mbox

[v3,11/12] mmc: sunxi: Convert MMC driver to the standard clock phase API

Message ID 1410466706-27386-12-git-send-email-maxime.ripard@free-electrons.com
State Accepted, archived
Headers show

Commit Message

Maxime Ripard Sept. 11, 2014, 8:18 p.m. UTC 
Now that we have proper support to use the generic phase API in our clock
driver, switch the MMC driver to use it.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 .../devicetree/bindings/mmc/sunxi-mmc.txt          |  8 +--
 drivers/mmc/host/sunxi-mmc.c                       | 72 +++++++++++++++-------
 2 files changed, 53 insertions(+), 27 deletions(-)

Comments

David Lanzendörfer Sept. 26, 2014, 2:27 p.m. UTC | #1 
Hello
> Now that we have proper support to use the generic phase API in our clock
> driver, switch the MMC driver to use it.
> [...]
>  	/* determine delays */
>  	if (rate <= 400000) {
> -		oclk_dly = 0;
> -		sclk_dly = 7;
> +		oclk_dly = 180;
> +		sclk_dly = 42;
> [...]
How did you calculate the actual phase values from the original parameters?

greatings
Maxime Ripard Sept. 26, 2014, 3:02 p.m. UTC | #2 
On Fri, Sep 26, 2014 at 04:27:10PM +0200, David Lanzendörfer wrote:
> Hello
> > Now that we have proper support to use the generic phase API in our clock
> > driver, switch the MMC driver to use it.
> > [...]
> >  	/* determine delays */
> >  	if (rate <= 400000) {
> > -		oclk_dly = 0;
> > -		sclk_dly = 7;
> > +		oclk_dly = 180;
> > +		sclk_dly = 42;
> > [...]
> How did you calculate the actual phase values from the original parameters?

Like shown in the clock driver. 0 is always a 180 deg phase shift, and
any other value is the number of the parent clock cycle to outphase
the clock of.

the clock out phase is calculating using:

phase = 360 * interval / period.

with period = 1 / (parent_freq / divider)
and interval = reg / parent_freq

which makes

phase = 360 * (reg / parent_freq) * (parent_freq / divider)

If we simplify by removing the parent_freq, we end up with

phase = 360 * reg / divider, which makes it rather trivial to
calculate.

Maxime
David Lanzendörfer Sept. 26, 2014, 8:47 p.m. UTC | #3 
Hi
Great! Since I didn't see any mistakes from my side it shouldn't be a problem.
Because someone has borrowed my UART2USB(FT232)-cable I unfortunately can't
test the code for now.
If you can verfiy that all the adaptions are working properly on A10/A20 and
all the others you my assume my:
	Acked-by: David Lanzendörfer <david.lanzendoerfer@o2s.ch>

chears and all the best
david

> > > [...]
> > How did you calculate the actual phase values from the original
> > parameters?
>
> Like shown in the clock driver. 0 is always a 180 deg phase shift, and
> any other value is the number of the parent clock cycle to outphase
> the clock of.
> 
> the clock out phase is calculating using:
> 
> phase = 360 * interval / period.
> 
> with period = 1 / (parent_freq / divider)
> and interval = reg / parent_freq
> 
> which makes
> 
> phase = 360 * (reg / parent_freq) * (parent_freq / divider)
> 
> If we simplify by removing the parent_freq, we end up with
> 
> phase = 360 * reg / divider, which makes it rather trivial to
> calculate.
> 
> Maxime
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt b/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt
index 91b3a3467150..4bf41d833804 100644
--- a/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt
@@ -10,8 +10,8 @@  Absolute maximum transfer rate is 200MB/s
 Required properties:
  - compatible : "allwinner,sun4i-a10-mmc" or "allwinner,sun5i-a13-mmc"
  - reg : mmc controller base registers
- - clocks : a list with 2 phandle + clock specifier pairs
- - clock-names : must contain "ahb" and "mmc"
+ - clocks : a list with 4 phandle + clock specifier pairs
+ - clock-names : must contain "ahb", "mmc", "output" and "sample"
  - interrupts : mmc controller interrupt
 
 Optional properties:
@@ -25,8 +25,8 @@  Examples:
 	mmc0: mmc@01c0f000 {
 		compatible = "allwinner,sun5i-a13-mmc";
 		reg = <0x01c0f000 0x1000>;
-		clocks = <&ahb_gates 8>, <&mmc0_clk>;
-		clock-names = "ahb", "mod";
+		clocks = <&ahb_gates 8>, <&mmc0_clk>, <&mmc0_output_clk>, <&mmc0_sample_clk>;
+		clock-names = "ahb", "mod", "output", "sample";
 		interrupts = <0 32 4>;
 		status = "disabled";
 	};
diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index 024f67c98cdc..8719cefa590d 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -22,7 +22,6 @@ 
 
 #include <linux/clk.h>
 #include <linux/clk-private.h>
-#include <linux/clk/sunxi.h>
 
 #include <linux/gpio.h>
 #include <linux/platform_device.h>
@@ -230,6 +229,8 @@  struct sunxi_mmc_host {
 	/* clock management */
 	struct clk	*clk_ahb;
 	struct clk	*clk_mmc;
+	struct clk	*clk_sample;
+	struct clk	*clk_output;
 
 	/* irq */
 	spinlock_t	lock;
@@ -617,7 +618,7 @@  static int sunxi_mmc_oclk_onoff(struct sunxi_mmc_host *host, u32 oclk_en)
 static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
 				  struct mmc_ios *ios)
 {
-	u32 rate, oclk_dly, rval, sclk_dly, src_clk;
+	u32 rate, oclk_dly, rval, sclk_dly;
 	int ret;
 
 	rate = clk_round_rate(host->clk_mmc, ios->clock);
@@ -643,34 +644,31 @@  static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
 
 	/* determine delays */
 	if (rate <= 400000) {
-		oclk_dly = 0;
-		sclk_dly = 7;
+		oclk_dly = 180;
+		sclk_dly = 42;
 	} else if (rate <= 25000000) {
-		oclk_dly = 0;
-		sclk_dly = 5;
+		oclk_dly = 180;
+		sclk_dly = 75;
 	} else if (rate <= 50000000) {
 		if (ios->timing == MMC_TIMING_UHS_DDR50) {
-			oclk_dly = 2;
-			sclk_dly = 4;
+			oclk_dly = 60;
+			sclk_dly = 120;
 		} else {
-			oclk_dly = 3;
-			sclk_dly = 5;
+			oclk_dly = 90;
+			sclk_dly = 150;
 		}
+	} else if (rate <= 100000000) {
+		oclk_dly = 6;
+		sclk_dly = 24;
+	} else if (rate <= 200000000) {
+		oclk_dly = 3;
+		sclk_dly = 12;
 	} else {
-		/* rate > 50000000 */
-		oclk_dly = 2;
-		sclk_dly = 4;
+		return -EINVAL;
 	}
 
-	src_clk = clk_get_rate(clk_get_parent(host->clk_mmc));
-	if (src_clk >= 300000000 && src_clk <= 400000000) {
-		if (oclk_dly)
-			oclk_dly--;
-		if (sclk_dly)
-			sclk_dly--;
-	}
-
-	clk_sunxi_mmc_phase_control(host->clk_mmc, sclk_dly, oclk_dly);
+	clk_set_phase(host->clk_sample, sclk_dly);
+	clk_set_phase(host->clk_output, oclk_dly);
 
 	return sunxi_mmc_oclk_onoff(host, 1);
 }
@@ -909,6 +907,18 @@  static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
 		return PTR_ERR(host->clk_mmc);
 	}
 
+	host->clk_output = devm_clk_get(&pdev->dev, "output");
+	if (IS_ERR(host->clk_output)) {
+		dev_err(&pdev->dev, "Could not get output clock\n");
+		return PTR_ERR(host->clk_output);
+	}
+
+	host->clk_sample = devm_clk_get(&pdev->dev, "sample");
+	if (IS_ERR(host->clk_sample)) {
+		dev_err(&pdev->dev, "Could not get sample clock\n");
+		return PTR_ERR(host->clk_sample);
+	}
+
 	host->reset = devm_reset_control_get(&pdev->dev, "ahb");
 
 	ret = clk_prepare_enable(host->clk_ahb);
@@ -923,11 +933,23 @@  static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
 		goto error_disable_clk_ahb;
 	}
 
+	ret = clk_prepare_enable(host->clk_output);
+	if (ret) {
+		dev_err(&pdev->dev, "Enable output clk err %d\n", ret);
+		goto error_disable_clk_mmc;
+	}
+
+	ret = clk_prepare_enable(host->clk_sample);
+	if (ret) {
+		dev_err(&pdev->dev, "Enable sample clk err %d\n", ret);
+		goto error_disable_clk_output;
+	}
+
 	if (!IS_ERR(host->reset)) {
 		ret = reset_control_deassert(host->reset);
 		if (ret) {
 			dev_err(&pdev->dev, "reset err %d\n", ret);
-			goto error_disable_clk_mmc;
+			goto error_disable_clk_sample;
 		}
 	}
 
@@ -946,6 +968,10 @@  static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
 error_assert_reset:
 	if (!IS_ERR(host->reset))
 		reset_control_assert(host->reset);
+error_disable_clk_sample:
+	clk_disable_unprepare(host->clk_sample);
+error_disable_clk_output:
+	clk_disable_unprepare(host->clk_output);
 error_disable_clk_mmc:
 	clk_disable_unprepare(host->clk_mmc);
 error_disable_clk_ahb: