[v2,06/14] ARM: davinci: da850: model the SATA refclk

Message ID 1484655976-25382-7-git-send-email-bgolaszewski@baylibre.com
State New
Headers show
Series
  • ARM: da850-lcdk: add SATA support
Related show

Commit Message

Bartosz Golaszewski Jan. 17, 2017, 12:26 p.m.
Register a dummy clock modelling the external SATA oscillator for
da850 DT mode. For non-DT boot we don't register the clock - instead
we rely on the default MPY value defined in the da850 ahci driver (as
is done currently).

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

---
 arch/arm/mach-davinci/da8xx-dt.c           |  8 ++++++++
 arch/arm/mach-davinci/devices-da8xx.c      | 23 +++++++++++++++++++++++
 arch/arm/mach-davinci/include/mach/da8xx.h |  1 +
 3 files changed, 32 insertions(+)

-- 
2.9.3


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Comments

David Lechner Jan. 17, 2017, 6:40 p.m. | #1
On 01/17/2017 06:26 AM, Bartosz Golaszewski wrote:
> Register a dummy clock modelling the external SATA oscillator for

> da850 DT mode. For non-DT boot we don't register the clock - instead

> we rely on the default MPY value defined in the da850 ahci driver (as

> is done currently).


Why not register a clock for non-DT boot as well?



_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Sekhar Nori Jan. 18, 2017, 9:02 a.m. | #2
On Tuesday 17 January 2017 05:56 PM, Bartosz Golaszewski wrote:
> Register a dummy clock modelling the external SATA oscillator for


I would not call it a dummy clock. Its representing something physically
present. Just call it "fixed rate clock" ?

> da850 DT mode. For non-DT boot we don't register the clock - instead

> we rely on the default MPY value defined in the da850 ahci driver (as

> is done currently).


Here too, like David suggested, it will be nice to register it both for
DT and non-DT case. With that I think your driver will be simple too
since you dont have to worry about the case when refclkpn is not supplied.

> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

> ---

>  arch/arm/mach-davinci/da8xx-dt.c           |  8 ++++++++

>  arch/arm/mach-davinci/devices-da8xx.c      | 23 +++++++++++++++++++++++

>  arch/arm/mach-davinci/include/mach/da8xx.h |  1 +

>  3 files changed, 32 insertions(+)

> 

> diff --git a/arch/arm/mach-davinci/da8xx-dt.c b/arch/arm/mach-davinci/da8xx-dt.c

> index b83e5d1..13137cb 100644

> --- a/arch/arm/mach-davinci/da8xx-dt.c

> +++ b/arch/arm/mach-davinci/da8xx-dt.c

> @@ -61,6 +61,14 @@ static void __init da850_init_machine(void)

>  		pr_warn("%s: registering USB 1.1 PHY clock failed: %d",

>  			__func__, ret);

>  

> +	if (of_machine_is_compatible("ti,da850-evm") ||

> +	    of_machine_is_compatible("ti,da850-lcdk")) {

> +		ret = da850_register_sata_refclk(100000000);

> +		if (ret)

> +			pr_warn("%s: registering SATA_REFCLK clock failed: %d",

> +				__func__, ret);

> +	}


Since all supported boards use 100 Mhz refclk anyway, I would drop the
machine check and just do:

	/* All existing boards use 100MHz SATA refclkpn */
	unsigned long sata_refclkpn = 100 * 1000 * 1000;

	ret = da850_register_sata_refclk(sata_refclkpn);

It should then be easy for the odd board (when it comes) to set
sata_refclkpn to a different value.

Thanks,
Sekhar


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Patch

diff --git a/arch/arm/mach-davinci/da8xx-dt.c b/arch/arm/mach-davinci/da8xx-dt.c
index b83e5d1..13137cb 100644
--- a/arch/arm/mach-davinci/da8xx-dt.c
+++ b/arch/arm/mach-davinci/da8xx-dt.c
@@ -61,6 +61,14 @@  static void __init da850_init_machine(void)
 		pr_warn("%s: registering USB 1.1 PHY clock failed: %d",
 			__func__, ret);
 
+	if (of_machine_is_compatible("ti,da850-evm") ||
+	    of_machine_is_compatible("ti,da850-lcdk")) {
+		ret = da850_register_sata_refclk(100000000);
+		if (ret)
+			pr_warn("%s: registering SATA_REFCLK clock failed: %d",
+				__func__, ret);
+	}
+
 	of_platform_default_populate(NULL, da850_auxdata_lookup, NULL);
 	davinci_pm_init();
 }
diff --git a/arch/arm/mach-davinci/devices-da8xx.c b/arch/arm/mach-davinci/devices-da8xx.c
index c2457b3..2bb5b69 100644
--- a/arch/arm/mach-davinci/devices-da8xx.c
+++ b/arch/arm/mach-davinci/devices-da8xx.c
@@ -24,6 +24,7 @@ 
 #include <mach/common.h>
 #include <mach/time.h>
 #include <mach/da8xx.h>
+#include <mach/clock.h>
 #include "cpuidle.h"
 #include "sram.h"
 
@@ -1023,6 +1024,28 @@  int __init da8xx_register_spi_bus(int instance, unsigned num_chipselect)
 }
 
 #ifdef CONFIG_ARCH_DAVINCI_DA850
+static struct clk sata_refclk = {
+	.name		= "sata_refclk",
+	.set_rate	= davinci_simple_set_rate,
+};
+
+static struct clk_lookup sata_refclk_lookup =
+		CLK("ahci_da850", "refclk", &sata_refclk);
+
+int __init da850_register_sata_refclk(int rate)
+{
+	int ret;
+
+	sata_refclk.rate = rate;
+	ret = clk_register(&sata_refclk);
+	if (ret)
+		return ret;
+
+	clkdev_add(&sata_refclk_lookup);
+
+	return 0;
+}
+
 static struct resource da850_sata_resources[] = {
 	{
 		.start	= DA850_SATA_BASE,
diff --git a/arch/arm/mach-davinci/include/mach/da8xx.h b/arch/arm/mach-davinci/include/mach/da8xx.h
index 85ff218..7e46422 100644
--- a/arch/arm/mach-davinci/include/mach/da8xx.h
+++ b/arch/arm/mach-davinci/include/mach/da8xx.h
@@ -95,6 +95,7 @@  int da8xx_register_usb11(struct da8xx_ohci_root_hub *pdata);
 int da8xx_register_usb_refclkin(int rate);
 int da8xx_register_usb20_phy_clk(bool use_usb_refclkin);
 int da8xx_register_usb11_phy_clk(bool use_usb_refclkin);
+int da850_register_sata_refclk(int rate);
 int da8xx_register_emac(void);
 int da8xx_register_uio_pruss(void);
 int da8xx_register_lcdc(struct da8xx_lcdc_platform_data *pdata);