Re: [PATCH 6/6] clk: samsung: Introduce Exynos850 clock driver

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Hi Sam,

On 21. 9. 15. 오전 12:56, Sam Protsenko wrote:
This is the initial implementation adding only basic clocks like UART,
MMC, I2C and corresponding parent clocks. Design is influenced by
Exynos7 and Exynos5433 clock drivers.

Signed-off-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
---
  drivers/clk/samsung/Makefile        |   1 +
  drivers/clk/samsung/clk-exynos850.c | 700 ++++++++++++++++++++++++++++
  2 files changed, 701 insertions(+)
  create mode 100644 drivers/clk/samsung/clk-exynos850.c

diff --git a/drivers/clk/samsung/Makefile b/drivers/clk/samsung/Makefile
index 028b2e27a37e..c46cf11e4d0b 100644
--- a/drivers/clk/samsung/Makefile
+++ b/drivers/clk/samsung/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_EXYNOS_ARM64_COMMON_CLK)	+= clk-exynos5433.o
  obj-$(CONFIG_EXYNOS_AUDSS_CLK_CON) += clk-exynos-audss.o
  obj-$(CONFIG_EXYNOS_CLKOUT)	+= clk-exynos-clkout.o
  obj-$(CONFIG_EXYNOS_ARM64_COMMON_CLK)	+= clk-exynos7.o
+obj-$(CONFIG_EXYNOS_ARM64_COMMON_CLK)	+= clk-exynos850.o
  obj-$(CONFIG_S3C2410_COMMON_CLK)+= clk-s3c2410.o
  obj-$(CONFIG_S3C2410_COMMON_DCLK)+= clk-s3c2410-dclk.o
  obj-$(CONFIG_S3C2412_COMMON_CLK)+= clk-s3c2412.o
diff --git a/drivers/clk/samsung/clk-exynos850.c b/drivers/clk/samsung/clk-exynos850.c
new file mode 100644
index 000000000000..1028caa2102e
--- /dev/null
+++ b/drivers/clk/samsung/clk-exynos850.c
@@ -0,0 +1,700 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 Linaro Ltd.
+ * Author: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
+ *
+ * Common Clock Framework support for Exynos850 SoC.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include <dt-bindings/clock/exynos850.h>
+
+#include "clk.h"
+
+/* Gate register bits */
+#define GATE_MANUAL		BIT(20)
+#define GATE_ENABLE_HWACG	BIT(28)
+
+/* Gate register offsets range */
+#define GATE_OFF_START		0x2000
+#define GATE_OFF_END		0x2fff
+
+/**
+ * exynos850_init_clocks - Set clocks initial configuration
+ * @np:			CMU device tree node with "reg" property (CMU addr)
+ * @reg_offs:		Register offsets array for clocks to init
+ * @reg_offs_len:	Number of register offsets in reg_offs array
+ *
+ * Set manual control mode for all gate clocks.
+ */
+static void __init exynos850_init_clocks(struct device_node *np,
+		const unsigned long *reg_offs, size_t reg_offs_len)
+{
+	const __be32 *regaddr_p;
+	u64 regaddr;
+	u32 base;
+	size_t i;
+
+	/* Get the base address ("reg" property in dts) */
+	regaddr_p = of_get_address(np, 0, NULL, NULL);
+	if (!regaddr_p)
+		panic("%s: failed to get reg regaddr\n", __func__);
+
+	regaddr = of_translate_address(np, regaddr_p);
+	if (regaddr == OF_BAD_ADDR || !regaddr)
+		panic("%s: bad reg regaddr\n", __func__);
+
+	base = (u32)regaddr;
+
+	for (i = 0; i < reg_offs_len; ++i) {
+		void __iomem *reg;
+		u32 val;
+
+		/* Modify only gate clock registers */
+		if (reg_offs[i] < GATE_OFF_START || reg_offs[i] > GATE_OFF_END)
+			continue; > +
+		reg = ioremap(base + reg_offs[i], 4);
+		val = ioread32(reg);
+		val |= GATE_MANUAL;
+		val &= ~GATE_ENABLE_HWACG;
+		iowrite32(val, reg);
+		iounmap(reg);

I understand your intention for disabling HWACG.
But, it is not good to execute ioreamp/iounmap for each clock gate
register. I think that we need to consider the more pretty method
to initialize the clock register before clock registration.

[snip]

--
Best Regards,
Samsung Electronics
Chanwoo Choi



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