[PATCH 07/10] sata: ahci_da850: add support for the da850,clk_multiplier DT property
From: david@lechnology.com (David Lechner)
Date: 2017-01-13 20:36:21
Also in:
linux-devicetree, linux-ide, lkml
On 01/13/2017 06:38 AM, Bartosz Golaszewski wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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.
quoted hunk ↗ jump to hunk
*/ -#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);