linux-kernel - [RFC PATCH 08/11] clk: imx: gate2: add device tree support

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Message-Id: <20221231104736.12635-9-dario.binacchi@amarulasolutions.com>
Date:   Sat, 31 Dec 2022 11:47:33 +0100
From:   Dario Binacchi <dario.binacchi@...rulasolutions.com>
To:     linux-kernel@...r.kernel.org
Cc:     tommaso.merciai@...rulasolutions.com,
        linux-amarula@...rulasolutions.com,
        Chen-Yu Tsai <wenst@...omium.org>, jagan@...rulasolutions.com,
        angelo@...rulasolutions.com, anthony@...rulasolutions.com,
        michael@...rulasolutions.com,
        Dario Binacchi <dario.binacchi@...rulasolutions.com>,
        Abel Vesa <abelvesa@...nel.org>,
        Fabio Estevam <festevam@...il.com>,
        Michael Turquette <mturquette@...libre.com>,
        NXP Linux Team <linux-imx@....com>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org
Subject: [RFC PATCH 08/11] clk: imx: gate2: add device tree support

The patch, backwards compatible, extends the driver to initialize the
clock directly from the device tree.

Signed-off-by: Dario Binacchi <dario.binacchi@...rulasolutions.com>
---

 drivers/clk/imx/clk-gate2.c | 86 +++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/drivers/clk/imx/clk-gate2.c b/drivers/clk/imx/clk-gate2.c
index f16c4019f402..b28150bf1ff6 100644
--- a/drivers/clk/imx/clk-gate2.c
+++ b/drivers/clk/imx/clk-gate2.c
@@ -12,9 +12,26 @@
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/string.h>
 #include "clk.h"
 
+#define CLK_GATE2_CGR_DISABLED 0
+#define CLK_GATE2_CGR_RUN 1
+#define CLK_GATE2_CGR_RUN_WAIT 2
+#define CLK_GATE2_CGR_RUN_WAIT_STOP 3
+#define CLK_GATE2_CGR_MASK 3
+
+#define CLK_GATE2_MAX_GROUPS    16
+
+struct clk_gate2_group {
+	const char *name;
+	unsigned int share_count;
+};
+
+static struct clk_gate2_group clk_gate2_groups[CLK_GATE2_MAX_GROUPS];
+
 /**
  * DOC: basic gateable clock which can gate and ungate its output
  *
@@ -175,3 +192,72 @@ struct clk_hw *clk_hw_register_gate2(struct device *dev, const char *name,
 	return hw;
 }
 EXPORT_SYMBOL_GPL(clk_hw_register_gate2);
+
+/**
+ * of_imx_gate2_clk_setup() - Setup function for imx low power gate
+ *                            clock
+ * @node:	device node for the clock
+ */
+static void __init of_imx_gate2_clk_setup(struct device_node *node)
+{
+	void __iomem *reg;
+	u8 i, bit_idx = 0;
+	u8 cgr_val = CLK_GATE2_CGR_RUN_WAIT_STOP;
+	u8 cgr_mask = CLK_GATE2_CGR_MASK;
+	unsigned long flags = CLK_OPS_PARENT_ENABLE | CLK_SET_RATE_PARENT;
+	u8 gate2_flags = 0;
+	unsigned int *share_count = NULL;
+	const char *name = node->name, *parent_name;
+	const char *str;
+	struct clk_hw *hw;
+	u32 val;
+
+	reg = of_iomap(node, 0);
+	if (IS_ERR(reg)) {
+		pr_err("failed to get reg address for %pOFn\n", node);
+		return;
+	}
+
+	if (!of_property_read_u32(node, "fsl,bit-shift", &val))
+		bit_idx = val;
+
+	if (of_clk_get_parent_count(node) != 1) {
+		pr_err("%pOFn must have 1 parent clock\n", node);
+		return;
+	}
+
+	if (!of_property_read_string(node, "sharing-group", &str)) {
+		for (i = 0; clk_gate2_groups[i].name &&
+			     i < ARRAY_SIZE(clk_gate2_groups); i++) {
+			if (!strcmp(clk_gate2_groups[i].name, str)) {
+				share_count = &clk_gate2_groups[i].share_count;
+				break;
+			}
+		}
+
+		if (i == ARRAY_SIZE(clk_gate2_groups)) {
+			pr_err("failed to get shared count for %pOFn\n", node);
+			return;
+		}
+
+		if (!share_count) {
+			clk_gate2_groups[i].name =
+				kstrdup_const(str, GFP_KERNEL);
+			share_count = &clk_gate2_groups[i].share_count;
+		}
+	}
+
+	parent_name = of_clk_get_parent_name(node, 0);
+	of_property_read_string(node, "clock-output-names", &name);
+
+	hw = clk_hw_register_gate2(NULL, name, parent_name, flags, reg, bit_idx,
+				   cgr_val, cgr_mask, gate2_flags,
+				   &imx_ccm_lock, share_count);
+	if (!IS_ERR(hw))
+		of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
+
+	pr_debug("name: %s, parent: %s, enable-bit: %d, flags: 0x%lx, gate2_flags: 0x%x\n",
+		 name, parent_name, bit_idx, flags, gate2_flags);
+}
+CLK_OF_DECLARE(fsl_imx8mn_gate2_clk, "fsl,imx8mn-low-power-gate-clock",
+	       of_imx_gate2_clk_setup);
-- 
2.32.0