[PATCH v3 1/6] clk: sunxi-ng: a20: Register regmap for sun7i CCU

[Priit Laes]

On sun7i, the gmac clock is handled by the dwmac-sunxi driver, but
its configuration register is located in the CCU register range,
requiring proper regmap setup.

In order to do that, we use CLK_OF_DECLARE_DRIVER to initialize
sun7i ccu, which clears the OF_POPULATED flag, allowing the
platform device to probe the same resource with proper device node.

Signed-off-by: Priit Laes <plaes@xxxxxxxxx>
---
 drivers/clk/sunxi-ng/ccu-sun4i-a10.c | 62 +++++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun4i-a10.c b/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
index f32366d9336e..fa147b8ce705 100644
--- a/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
+++ b/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
@@ -8,6 +8,8 @@
 #include <linux/clk-provider.h>
 #include <linux/io.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
 
 #include "ccu_common.h"
 #include "ccu_reset.h"
@@ -1478,5 +1480,61 @@ static void __init sun7i_a20_ccu_setup(struct device_node *node)
 {
 	sun4i_ccu_init(node, &sun7i_a20_ccu_desc);
 }
-CLK_OF_DECLARE(sun7i_a20_ccu, "allwinner,sun7i-a20-ccu",
-	       sun7i_a20_ccu_setup);
+CLK_OF_DECLARE_DRIVER(sun7i_a20_ccu, "allwinner,sun7i-a20-ccu",
+		      sun7i_a20_ccu_setup);
+
+/*
+ * Regmap for the GMAC driver (dwmac-sunxi) to allow access to
+ * GMAC configuration register.
+ */
+#define SUN7I_A20_GMAC_CFG_REG 0x164
+static bool sun7i_a20_ccu_regmap_accessible_reg(struct device *dev,
+						unsigned int reg)
+{
+	if (reg == SUN7I_A20_GMAC_CFG_REG)
+		return true;
+	return false;
+}
+
+static struct regmap_config sun7i_a20_ccu_regmap_config = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+	.max_register	= 0x1f4, /* clk_out_b */
+
+	.readable_reg	= sun7i_a20_ccu_regmap_accessible_reg,
+	.writeable_reg	= sun7i_a20_ccu_regmap_accessible_reg,
+};
+
+static int sun7i_a20_ccu_probe_regmap(struct platform_device *pdev)
+{
+	void __iomem *reg;
+	struct resource *res;
+	struct regmap *regmap;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	reg = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+	if (IS_ERR(reg))
+		return PTR_ERR(reg);
+
+	regmap = devm_regmap_init_mmio(&pdev->dev, reg,
+				       &sun7i_a20_ccu_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	return 0;
+}
+
+static const struct of_device_id sun7i_a20_ccu_ids[] = {
+	{ .compatible = "allwinner,sun7i-a20-ccu"},
+	{ }
+};
+
+static struct platform_driver sun7i_a20_ccu_driver = {
+	.probe = sun7i_a20_ccu_probe_regmap,
+	.driver = {
+		.name = "sun7i-a20-ccu",
+		.of_match_table = sun7i_a20_ccu_ids,
+	},
+};
+builtin_platform_driver(sun7i_a20_ccu_driver);
-- 
2.26.2