[07/10] sata: ahci_da850: add support for the da850, clk_multiplier DT property

Message ID 1484311084-31547-8-git-send-email-bgolaszewski@baylibre.com
State New
Headers show

Commit Message

Bartosz Golaszewski Jan. 13, 2017, 12:38 p.m.
Currently the clock multiplier is hardcoded in the driver for
the da850-evm board. Make it configurable over DT, but keep the
previous value as default in case the property is missing.

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

---
 drivers/ata/ahci_da850.c | 83 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 75 insertions(+), 8 deletions(-)

-- 
2.9.3


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Comments

David Lechner Jan. 13, 2017, 7:29 p.m. | #1
On 01/13/2017 06:38 AM, Bartosz Golaszewski wrote:
> Currently the clock multiplier is hardcoded in the driver for

> the da850-evm board. Make it configurable over DT, but keep the

> previous value as default in case the property is missing.

>

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

> ---

>  drivers/ata/ahci_da850.c | 83 +++++++++++++++++++++++++++++++++++++++++++-----

>  1 file changed, 75 insertions(+), 8 deletions(-)

>

> diff --git a/drivers/ata/ahci_da850.c b/drivers/ata/ahci_da850.c

> index bb9eb4c..cd04caf 100644

> --- a/drivers/ata/ahci_da850.c

> +++ b/drivers/ata/ahci_da850.c

> @@ -28,17 +28,70 @@

>  #define SATA_PHY_TXSWING(x)	((x) << 19)

>  #define SATA_PHY_ENPLL(x)	((x) << 31)

>

> +struct da850_sata_mpy_mapping {

> +	unsigned int multiplier;

> +	unsigned int regval;

> +};

> +

> +static const struct da850_sata_mpy_mapping da850_sata_mpy_table[] = {

> +	{

> +		.multiplier	= 5,

> +		.regval		= 0x01,

> +	},

> +	{

> +		.multiplier	= 6,

> +		.regval		= 0x02,

> +	},

> +	{

> +		.multiplier	= 8,

> +		.regval		= 0x04,

> +	},

> +	{

> +		.multiplier	= 10,

> +		.regval		= 0x05,

> +	},

> +	{

> +		.multiplier	= 12,

> +		.regval		= 0x06,

> +	},

> +	/* TODO Add 12.5 multiplier. */


Looks like you should be using an enum here for the multiplier field.

> +	{

> +		.multiplier	= 15,

> +		.regval		= 0x08,

> +	},

> +	{

> +		.multiplier	= 20,

> +		.regval		= 0x09,

> +	},

> +	{

> +		.multiplier	= 25,

> +		.regval		= 0x0a,

> +	}

> +};

> +

> +static const struct da850_sata_mpy_mapping *

> +da850_sata_get_mpy(unsigned int multiplier)

> +{

> +	int i;

> +

> +	for (i = 0; i < ARRAY_SIZE(da850_sata_mpy_table); i++)

> +		if (da850_sata_mpy_table[i].multiplier == multiplier)

> +			return &da850_sata_mpy_table[i];

> +

> +	return NULL;

> +}

> +

>  /*

>   * The multiplier needed for 1.5GHz PLL output.

>   *

> - * NOTE: This is currently hardcoded to be suitable for 100MHz crystal

> - * frequency (which is used by DA850 EVM board) and may need to be changed

> - * if you would like to use this driver on some other board.

> + * This is the default value suitable for the 100MHz crystal frequency

> + * used by DA850 EVM board, which doesn't use DT.


As I said in a reply on another patch, it seems like it would be better 
to use a clock that represents the crystal and use clk_get_rate() and 
calculate the multiplier from that.

For example, we have done something like this in 
usb20_phy_clk_set_parent() in arch/arm/mach-davinci/usb-da8xx.c.

>   */

> -#define DA850_SATA_CLK_MULTIPLIER	7

> +#define DA850_SATA_CLK_MULTIPLIER_DEFAULT	15

>

>  static void da850_sata_init(struct device *dev, void __iomem *pwrdn_reg,

> -			    void __iomem *ahci_base)

> +			    void __iomem *ahci_base,

> +			    const struct da850_sata_mpy_mapping *mpy)

>  {

>  	unsigned int val;

>

> @@ -47,7 +100,7 @@ static void da850_sata_init(struct device *dev, void __iomem *pwrdn_reg,

>  	val &= ~BIT(0);

>  	writel(val, pwrdn_reg);

>

> -	val = SATA_PHY_MPY(DA850_SATA_CLK_MULTIPLIER + 1) | SATA_PHY_LOS(1) |

> +	val = SATA_PHY_MPY(mpy->regval) | SATA_PHY_LOS(1) |

>  	      SATA_PHY_RXCDR(4) | SATA_PHY_RXEQ(1) | SATA_PHY_TXSWING(3) |

>  	      SATA_PHY_ENPLL(1);

>

> @@ -87,10 +140,12 @@ static struct scsi_host_template ahci_platform_sht = {

>

>  static int ahci_da850_probe(struct platform_device *pdev)

>  {

> +	const struct da850_sata_mpy_mapping *mpy;

>  	struct device *dev = &pdev->dev;

>  	struct ahci_host_priv *hpriv;

> -	struct resource *res;

> +	unsigned int multiplier;

>  	void __iomem *pwrdn_reg;

> +	struct resource *res;

>  	int rc;

>

>  	hpriv = ahci_platform_get_resources(pdev);

> @@ -109,7 +164,19 @@ static int ahci_da850_probe(struct platform_device *pdev)

>  	if (!pwrdn_reg)

>  		goto disable_resources;

>

> -	da850_sata_init(dev, pwrdn_reg, hpriv->mmio);

> +	rc = of_property_read_u32(dev->of_node,

> +				  "da850,clk_multiplier", &multiplier);

> +	if (rc)

> +		multiplier = DA850_SATA_CLK_MULTIPLIER_DEFAULT;

> +

> +	mpy = da850_sata_get_mpy(multiplier);

> +	if (!mpy) {

> +		dev_err(dev, "invalid multiplier value: %u\n", multiplier);

> +		rc = -EINVAL;

> +		goto disable_resources;

> +	}

> +

> +	da850_sata_init(dev, pwrdn_reg, hpriv->mmio, mpy);

>

>  	rc = ahci_platform_init_host(pdev, hpriv, &ahci_da850_port_info,

>  				     &ahci_platform_sht);

>



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Patch

diff --git a/drivers/ata/ahci_da850.c b/drivers/ata/ahci_da850.c
index bb9eb4c..cd04caf 100644
--- a/drivers/ata/ahci_da850.c
+++ b/drivers/ata/ahci_da850.c
@@ -28,17 +28,70 @@ 
 #define SATA_PHY_TXSWING(x)	((x) << 19)
 #define SATA_PHY_ENPLL(x)	((x) << 31)
 
+struct da850_sata_mpy_mapping {
+	unsigned int multiplier;
+	unsigned int regval;
+};
+
+static const struct da850_sata_mpy_mapping da850_sata_mpy_table[] = {
+	{
+		.multiplier	= 5,
+		.regval		= 0x01,
+	},
+	{
+		.multiplier	= 6,
+		.regval		= 0x02,
+	},
+	{
+		.multiplier	= 8,
+		.regval		= 0x04,
+	},
+	{
+		.multiplier	= 10,
+		.regval		= 0x05,
+	},
+	{
+		.multiplier	= 12,
+		.regval		= 0x06,
+	},
+	/* TODO Add 12.5 multiplier. */
+	{
+		.multiplier	= 15,
+		.regval		= 0x08,
+	},
+	{
+		.multiplier	= 20,
+		.regval		= 0x09,
+	},
+	{
+		.multiplier	= 25,
+		.regval		= 0x0a,
+	}
+};
+
+static const struct da850_sata_mpy_mapping *
+da850_sata_get_mpy(unsigned int multiplier)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(da850_sata_mpy_table); i++)
+		if (da850_sata_mpy_table[i].multiplier == multiplier)
+			return &da850_sata_mpy_table[i];
+
+	return NULL;
+}
+
 /*
  * The multiplier needed for 1.5GHz PLL output.
  *
- * NOTE: This is currently hardcoded to be suitable for 100MHz crystal
- * frequency (which is used by DA850 EVM board) and may need to be changed
- * if you would like to use this driver on some other board.
+ * This is the default value suitable for the 100MHz crystal frequency
+ * used by DA850 EVM board, which doesn't use DT.
  */
-#define DA850_SATA_CLK_MULTIPLIER	7
+#define DA850_SATA_CLK_MULTIPLIER_DEFAULT	15
 
 static void da850_sata_init(struct device *dev, void __iomem *pwrdn_reg,
-			    void __iomem *ahci_base)
+			    void __iomem *ahci_base,
+			    const struct da850_sata_mpy_mapping *mpy)
 {
 	unsigned int val;
 
@@ -47,7 +100,7 @@  static void da850_sata_init(struct device *dev, void __iomem *pwrdn_reg,
 	val &= ~BIT(0);
 	writel(val, pwrdn_reg);
 
-	val = SATA_PHY_MPY(DA850_SATA_CLK_MULTIPLIER + 1) | SATA_PHY_LOS(1) |
+	val = SATA_PHY_MPY(mpy->regval) | SATA_PHY_LOS(1) |
 	      SATA_PHY_RXCDR(4) | SATA_PHY_RXEQ(1) | SATA_PHY_TXSWING(3) |
 	      SATA_PHY_ENPLL(1);
 
@@ -87,10 +140,12 @@  static struct scsi_host_template ahci_platform_sht = {
 
 static int ahci_da850_probe(struct platform_device *pdev)
 {
+	const struct da850_sata_mpy_mapping *mpy;
 	struct device *dev = &pdev->dev;
 	struct ahci_host_priv *hpriv;
-	struct resource *res;
+	unsigned int multiplier;
 	void __iomem *pwrdn_reg;
+	struct resource *res;
 	int rc;
 
 	hpriv = ahci_platform_get_resources(pdev);
@@ -109,7 +164,19 @@  static int ahci_da850_probe(struct platform_device *pdev)
 	if (!pwrdn_reg)
 		goto disable_resources;
 
-	da850_sata_init(dev, pwrdn_reg, hpriv->mmio);
+	rc = of_property_read_u32(dev->of_node,
+				  "da850,clk_multiplier", &multiplier);
+	if (rc)
+		multiplier = DA850_SATA_CLK_MULTIPLIER_DEFAULT;
+
+	mpy = da850_sata_get_mpy(multiplier);
+	if (!mpy) {
+		dev_err(dev, "invalid multiplier value: %u\n", multiplier);
+		rc = -EINVAL;
+		goto disable_resources;
+	}
+
+	da850_sata_init(dev, pwrdn_reg, hpriv->mmio, mpy);
 
 	rc = ahci_platform_init_host(pdev, hpriv, &ahci_da850_port_info,
 				     &ahci_platform_sht);