[PATCH v2 08/23] ata: libahci_platform: Add function returning a clock-handle by id

[Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>]

Since all the clocks are retrieved by the method
ahci_platform_get_resources() there is no need for the LLD (glue) drivers
to be looking for some particular of them in the kernel clocks table
again. Instead we suggest to add a simple method returning a
device-specific clock with passed connection ID if it is managed to be
found. Otherwise the function will return NULL. Thus the glue-drivers
won't need to either manually touching the hpriv->clks array or calling
clk_get()-friends. The AHCI platform drivers will be able to use the new
function right after the ahci_platform_get_resources() method invocation
and up to the device removal.

Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>

---

Changelog v2:
- Fix some grammar mistakes in the method description.
---
 drivers/ata/libahci_platform.c | 27 +++++++++++++++++++++++++++
 include/linux/ahci_platform.h  |  3 +++
 2 files changed, 30 insertions(+)

diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
index 3cff86c225fd..7ff6626fd569 100644
--- a/drivers/ata/libahci_platform.c
+++ b/drivers/ata/libahci_platform.c
@@ -94,6 +94,33 @@ void ahci_platform_disable_phys(struct ahci_host_priv *hpriv)
 }
 EXPORT_SYMBOL_GPL(ahci_platform_disable_phys);
 
+/**
+ * ahci_platform_find_clk - Find platform clock
+ * @hpriv: host private area to store config values
+ * @con_id: clock connection ID
+ *
+ * This function returns a pointer to the clock descriptor of the clock with
+ * the passed ID.
+ *
+ * RETURNS:
+ * Pointer to the clock descriptor on success otherwise NULL
+ */
+struct clk *ahci_platform_find_clk(struct ahci_host_priv *hpriv, const char *con_id)
+{
+	struct clk *clk = NULL;
+	int i;
+
+	for (i = 0; i < hpriv->n_clks; i++) {
+		if (!strcmp(hpriv->clks[i].id, con_id)) {
+			clk = hpriv->clks[i].clk;
+			break;
+		}
+	}
+
+	return clk;
+}
+EXPORT_SYMBOL_GPL(ahci_platform_find_clk);
+
 /**
  * ahci_platform_enable_clks - Enable platform clocks
  * @hpriv: host private area to store config values
diff --git a/include/linux/ahci_platform.h b/include/linux/ahci_platform.h
index 49e5383d4222..fd964e6a68d6 100644
--- a/include/linux/ahci_platform.h
+++ b/include/linux/ahci_platform.h
@@ -13,6 +13,7 @@
 
 #include <linux/compiler.h>
 
+struct clk;
 struct device;
 struct ata_port_info;
 struct ahci_host_priv;
@@ -21,6 +22,8 @@ struct scsi_host_template;
 
 int ahci_platform_enable_phys(struct ahci_host_priv *hpriv);
 void ahci_platform_disable_phys(struct ahci_host_priv *hpriv);
+struct clk *
+ahci_platform_find_clk(struct ahci_host_priv *hpriv, const char *con_id);
 int ahci_platform_enable_clks(struct ahci_host_priv *hpriv);
 void ahci_platform_disable_clks(struct ahci_host_priv *hpriv);
 int ahci_platform_enable_regulators(struct ahci_host_priv *hpriv);
-- 
2.35.1