clk: sunxi: Add driver for A80 MMC config clocks/resets

On the A80 SoC, the 4 mmc controllers each have a separate register
controlling their register access clocks and reset controls. These
registers in turn share a ahb clock gate and reset control.

This patch adds a platform device driver for these controls. It
requires both clocks and reset controls to be available, so using
CLK_OF_DECLARE might not be the best way.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

2 files changed, 220 insertions, 0 deletions

diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
index a66953c..3a5292e 100644
--- a/drivers/clk/sunxi/Makefile
+++ b/drivers/clk/sunxi/Makefile
@@ -8,6 +8,7 @@ obj-y += clk-a20-gmac.o
 obj-y += clk-mod0.o
 obj-y += clk-sun8i-mbus.o
 obj-y += clk-sun9i-core.o
+obj-y += clk-sun9i-mmc.o
 
 obj-$(CONFIG_MFD_SUN6I_PRCM) += \
 	clk-sun6i-ar100.o clk-sun6i-apb0.o clk-sun6i-apb0-gates.o \
diff --git a/drivers/clk/sunxi/clk-sun9i-mmc.c b/drivers/clk/sunxi/clk-sun9i-mmc.c
new file mode 100644
index 0000000..710c273
--- /dev/null
+++ b/drivers/clk/sunxi/clk-sun9i-mmc.c
@@ -0,0 +1,219 @@
+/*
+ * Copyright 2015 Chen-Yu Tsai
+ *
+ * Chen-Yu Tsai	<wens@csie.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/reset.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+
+#define SUN9I_MMC_WIDTH		4
+
+#define SUN9I_MMC_GATE_BIT	16
+#define SUN9I_MMC_RESET_BIT	18
+
+struct sun9i_mmc_clk_data {
+	spinlock_t			lock;
+	void __iomem			*membase;
+	struct clk			*clk;
+	struct reset_control		*reset;
+	struct clk_onecell_data		clk_data;
+	struct reset_controller_dev	rcdev;
+};
+
+static int sun9i_mmc_reset_assert(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	struct sun9i_mmc_clk_data *data = container_of(rcdev,
+						       struct sun9i_mmc_clk_data,
+						       rcdev);
+	unsigned long flags;
+	void __iomem *reg = data->membase + SUN9I_MMC_WIDTH * id;
+	u32 val;
+
+	clk_prepare_enable(data->clk);
+	spin_lock_irqsave(&data->lock, flags);
+
+	val = readl(reg);
+	writel(val & ~BIT(SUN9I_MMC_RESET_BIT), reg);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+	clk_disable_unprepare(data->clk);
+
+	return 0;
+}
+
+static int sun9i_mmc_reset_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	struct sun9i_mmc_clk_data *data = container_of(rcdev,
+						       struct sun9i_mmc_clk_data,
+						       rcdev);
+	unsigned long flags;
+	void __iomem *reg = data->membase + SUN9I_MMC_WIDTH * id;
+	u32 val;
+
+	clk_prepare_enable(data->clk);
+	spin_lock_irqsave(&data->lock, flags);
+
+	val = readl(reg);
+	writel(val | BIT(SUN9I_MMC_RESET_BIT), reg);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+	clk_disable_unprepare(data->clk);
+
+	return 0;
+}
+
+static struct reset_control_ops sun9i_mmc_reset_ops = {
+	.assert		= sun9i_mmc_reset_assert,
+	.deassert	= sun9i_mmc_reset_deassert,
+};
+
+static int sun9i_a80_mmc_config_clk_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct sun9i_mmc_clk_data *data;
+	struct clk_onecell_data *clk_data;
+	const char *clk_name = np->name;
+	const char *clk_parent;
+	struct resource *r;
+	int count, i, ret;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	spin_lock_init(&data->lock);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	/* one clock/reset pair per word */
+	count = DIV_ROUND_UP((r->end - r->start + 1), SUN9I_MMC_WIDTH);
+	data->membase = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(data->membase))
+		return PTR_ERR(data->membase);
+
+	clk_data = &data->clk_data;
+	clk_data->clk_num = count;
+	clk_data->clks = devm_kcalloc(&pdev->dev, count, sizeof(struct clk *),
+				      GFP_KERNEL);
+	if (!clk_data->clks)
+		return -ENOMEM;
+
+	data->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(data->clk)) {
+		dev_err(&pdev->dev, "Could not get clock\n");
+		return PTR_ERR(data->clk);
+	}
+
+	data->reset = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(data->reset)) {
+		dev_err(&pdev->dev, "Could not get reset control\n");
+		return PTR_ERR(data->reset);
+	}
+
+	ret = reset_control_deassert(data->reset);
+	if (ret) {
+		dev_err(&pdev->dev, "Reset deassert err %d\n", ret);
+		return ret;
+	}
+
+	clk_parent = __clk_get_name(data->clk);
+	for (i = 0; i < count; i++) {
+		of_property_read_string_index(np, "clock-output-names",
+					      i, &clk_name);
+
+		clk_data->clks[i] = clk_register_gate(&pdev->dev, clk_name,
+						      clk_parent, 0,
+						      data->membase + SUN9I_MMC_WIDTH * i,
+						      SUN9I_MMC_GATE_BIT, 0,
+						      &data->lock);
+
+		if (IS_ERR(clk_data->clks[i])) {
+			ret = PTR_ERR(clk_data->clks[i]);
+			goto err_clk_register;
+		}
+	}
+
+	ret = of_clk_add_provider(np, of_clk_src_onecell_get, clk_data);
+	if (ret)
+		goto err_clk_provider;
+
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.nr_resets = count;
+	data->rcdev.ops = &sun9i_mmc_reset_ops;
+	data->rcdev.of_node = pdev->dev.of_node;
+
+	ret = reset_controller_register(&data->rcdev);
+	if (ret)
+		goto err_rc_reg;
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+
+err_rc_reg:
+	of_clk_del_provider(np);
+
+err_clk_provider:
+	for (i = 0; i < count; i++)
+		clk_unregister(clk_data->clks[i]);
+
+err_clk_register:
+	reset_control_assert(data->reset);
+
+	return ret;
+}
+
+static int sun9i_a80_mmc_config_clk_remove(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct sun9i_mmc_clk_data *data = platform_get_drvdata(pdev);
+	struct clk_onecell_data *clk_data = &data->clk_data;
+	int i;
+
+	reset_controller_unregister(&data->rcdev);
+	of_clk_del_provider(np);
+	for (i = 0; i < clk_data->clk_num; i++)
+		clk_unregister(clk_data->clks[i]);
+
+	reset_control_assert(data->reset);
+
+	return 0;
+}
+
+static const struct of_device_id sun9i_a80_mmc_config_clk_dt_ids[] = {
+	{ .compatible = "allwinner,sun9i-a80-mmc-config-clk" },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver sun9i_a80_mmc_config_clk_driver = {
+	.driver = {
+		.name = "sun9i-a80-mmc-config-clk",
+		.of_match_table = sun9i_a80_mmc_config_clk_dt_ids,
+	},
+	.probe = sun9i_a80_mmc_config_clk_probe,
+	.remove = sun9i_a80_mmc_config_clk_remove,
+};
+module_platform_driver(sun9i_a80_mmc_config_clk_driver);
+
+MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
+MODULE_DESCRIPTION("Allwinner A80 MMC clock/reset Driver");
+MODULE_LICENSE("GPL v2");