Re: [PATCH v4 1/6] clk: hisilicon: add CRG driver for hi3519 soc

From: Philipp Zabel
Date: Tue Jan 05 2016 - 05:13:42 EST


H Jiancheng,

Am Mittwoch, den 30.12.2015, 09:43 +0800 schrieb Jiancheng Xue:
> The CRG(Clock and Reset Generator) block provides clock
> and reset signals for other modules in hi3519 soc.
>
> Signed-off-by: Jiancheng Xue <xuejiancheng@xxxxxxxxxx>
> ---
> .../devicetree/bindings/clock/hi3519-crg.txt | 46 +++++++
> drivers/clk/hisilicon/Kconfig | 7 +
> drivers/clk/hisilicon/Makefile | 2 +
> drivers/clk/hisilicon/clk-hi3519.c | 103 ++++++++++++++
> drivers/clk/hisilicon/reset.c | 149 +++++++++++++++++++++
> drivers/clk/hisilicon/reset.h | 32 +++++
> include/dt-bindings/clock/hi3519-clock.h | 43 ++++++
> 7 files changed, 382 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/clock/hi3519-crg.txt
> create mode 100644 drivers/clk/hisilicon/clk-hi3519.c
> create mode 100644 drivers/clk/hisilicon/reset.c
> create mode 100644 drivers/clk/hisilicon/reset.h
> create mode 100644 include/dt-bindings/clock/hi3519-clock.h
>
> diff --git a/Documentation/devicetree/bindings/clock/hi3519-crg.txt b/Documentation/devicetree/bindings/clock/hi3519-crg.txt
> new file mode 100644
> index 0000000..2d23950
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/hi3519-crg.txt
> @@ -0,0 +1,46 @@
> +* Hisilicon Hi3519 Clock and Reset Generator(CRG)
> +
> +The Hi3519 CRG module provides clock and reset signals to various
> +controllers within the SoC.
> +
> +This binding uses the following bindings:
> + Documentation/devicetree/bindings/clock/clock-bindings.txt
> + Documentation/devicetree/bindings/reset/reset.txt
> +
> +Required Properties:
> +
> +- compatible: should be one of the following.
> + - "hisilicon,hi3519-crg" - controller compatible with Hi3519 SoC.
> +
> +- reg: physical base address of the controller and length of memory mapped
> + region.
> +
> +- #clock-cells: should be 1.
> +
> +Each clock is assigned an identifier and client nodes use this identifier
> +to specify the clock which they consume.
> +
> +All these identifier could be found in <dt-bindings/clock/hi3519-clock.h>.
> +
> +- #reset-cells: should be 2.
> +
> +A reset signal can be controlled by writing a bit register in the CRG module.
> +The reset specifier consists of two cells. The first cell represents the
> +register offset relative to the base address. The second cell represents the
> +bit index in the register.

Are the resets controlled by single bits spread around the register
space? If so, I'm fine with this binding.

> +Example: CRG nodes
> +CRG: clock-reset-controller@12010000 {
> + compatible = "hisilicon,hi3519-crg";
> + reg = <0x12010000 0x10000>;
> + #clock-cells = <1>;
> + #reset-cells = <2>;
> +};
> +
> +Example: consumer nodes
> +i2c0: i2c@12110000 {
> + compatible = "hisilicon,hi3519-i2c";
> + reg = <0x12110000 0x1000>;
> + clocks = <&CRG HI3519_I2C0_RST>;*/
> + resets = <&CRG 0xe4 0>;
> +};
> diff --git a/drivers/clk/hisilicon/Kconfig b/drivers/clk/hisilicon/Kconfig
> index e434854..b6baebf 100644
> --- a/drivers/clk/hisilicon/Kconfig
> +++ b/drivers/clk/hisilicon/Kconfig
> @@ -1,3 +1,10 @@
> +config COMMON_CLK_HI3519
> + tristate "Clock Driver for Hi3519"
> + depends on ARCH_HISI
> + default y
> + help
> + Build the clock driver for hi3519.
> +
> config COMMON_CLK_HI6220
> bool "Hi6220 Clock Driver"
> depends on ARCH_HISI || COMPILE_TEST
> diff --git a/drivers/clk/hisilicon/Makefile b/drivers/clk/hisilicon/Makefile
> index 74dba31..3f57b09 100644
> --- a/drivers/clk/hisilicon/Makefile
> +++ b/drivers/clk/hisilicon/Makefile
> @@ -4,8 +4,10 @@
>
> obj-y += clk.o clkgate-separated.o clkdivider-hi6220.o
>
> +obj-$(CONFIG_RESET_CONTROLLER) += reset.o
> obj-$(CONFIG_ARCH_HI3xxx) += clk-hi3620.o
> obj-$(CONFIG_ARCH_HIP04) += clk-hip04.o
> obj-$(CONFIG_ARCH_HIX5HD2) += clk-hix5hd2.o
> obj-$(CONFIG_COMMON_CLK_HI6220) += clk-hi6220.o
> obj-$(CONFIG_STUB_CLK_HI6220) += clk-hi6220-stub.o
> +obj-$(CONFIG_COMMON_CLK_HI3519) += clk-hi3519.o
> diff --git a/drivers/clk/hisilicon/clk-hi3519.c b/drivers/clk/hisilicon/clk-hi3519.c
> new file mode 100644
> index 0000000..e220234
> --- /dev/null
> +++ b/drivers/clk/hisilicon/clk-hi3519.c
> @@ -0,0 +1,103 @@
> +/*
> + * Copyright (c) 2015 HiSilicon Technologies Co., Ltd.
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/of_address.h>
> +#include <dt-bindings/clock/hi3519-clock.h>
> +#include <linux/slab.h>
> +#include <linux/delay.h>
> +#include "clk.h"
> +#include "reset.h"
> +
> +#define HI3519_FIXED_24M (HI3519_EXT_CLKS + 1)
> +#define HI3519_FIXED_50M (HI3519_EXT_CLKS + 2)
> +#define HI3519_FIXED_75M (HI3519_EXT_CLKS + 3)
> +#define HI3519_FIXED_125M (HI3519_EXT_CLKS + 4)
> +#define HI3519_FIXED_150M (HI3519_EXT_CLKS + 5)
> +#define HI3519_FIXED_200M (HI3519_EXT_CLKS + 6)
> +#define HI3519_FIXED_250M (HI3519_EXT_CLKS + 7)
> +#define HI3519_FIXED_300M (HI3519_EXT_CLKS + 8)
> +#define HI3519_FIXED_400M (HI3519_EXT_CLKS + 9)
> +#define HI3519_FMC_MUX (HI3519_EXT_CLKS + 10)
> +
> +#define HI3519_NR_CLKS 128
> +#define HI3519_NR_RSTS 128
>+
> +static struct hisi_fixed_rate_clock hi3519_fixed_rate_clks[] __initdata = {
> + { HI3519_FIXED_3M, "3m", NULL, CLK_IS_ROOT, 3000000, },
> + { HI3519_FIXED_24M, "24m", NULL, CLK_IS_ROOT, 24000000, },
> + { HI3519_FIXED_50M, "50m", NULL, CLK_IS_ROOT, 50000000, },
> + { HI3519_FIXED_75M, "75m", NULL, CLK_IS_ROOT, 75000000, },
> + { HI3519_FIXED_125M, "125m", NULL, CLK_IS_ROOT, 125000000, },
> + { HI3519_FIXED_150M, "150m", NULL, CLK_IS_ROOT, 150000000, },
> + { HI3519_FIXED_200M, "200m", NULL, CLK_IS_ROOT, 200000000, },
> + { HI3519_FIXED_250M, "250m", NULL, CLK_IS_ROOT, 250000000, },
> + { HI3519_FIXED_300M, "300m", NULL, CLK_IS_ROOT, 300000000, },
> + { HI3519_FIXED_400M, "400m", NULL, CLK_IS_ROOT, 400000000, },
> +};
> +
> +static const char *fmc_mux_p[] __initconst = {
> + "24m", "75m", "125m", "150m", "200m", "250m", "300m", "400m", };
> +static u32 fmc_mux_table[] = {0, 1, 2, 3, 4, 5, 6, 7};
> +
> +static struct hisi_mux_clock hi3519_mux_clks[] __initdata = {
> + { HI3519_FMC_MUX, "fmc_mux", fmc_mux_p, ARRAY_SIZE(fmc_mux_p),
> + CLK_SET_RATE_PARENT, 0xc0, 2, 3, 0, fmc_mux_table, },
> +};
> +
> +static struct hisi_gate_clock hi3519_gate_clks[] __initdata = {
> + /* fmc */
> + { HI3519_FMC_CLK, "clk_fmc", "fmc_mux",
> + CLK_SET_RATE_PARENT, 0xc0, 1, 0, },
> + /* uart */
> + { HI3519_UART0_CLK, "clk_uart0", "24m",
> + CLK_SET_RATE_PARENT, 0xe4, 20, 0, },
> + { HI3519_UART1_CLK, "clk_uart1", "24m",
> + CLK_SET_RATE_PARENT, 0xe4, 21, 0, },
> + { HI3519_UART2_CLK, "clk_uart2", "24m",
> + CLK_SET_RATE_PARENT, 0xe4, 22, 0, },
> + { HI3519_UART3_CLK, "clk_uart3", "24m",
> + CLK_SET_RATE_PARENT, 0xe4, 23, 0, },
> + { HI3519_UART4_CLK, "clk_uart4", "24m",
> + CLK_SET_RATE_PARENT, 0xe4, 24, 0, },
> + { HI3519_SPI0_CLK, "clk_spi0", "50m",
> + CLK_SET_RATE_PARENT, 0xe4, 16, 0, },
> + { HI3519_SPI1_CLK, "clk_spi1", "50m",
> + CLK_SET_RATE_PARENT, 0xe4, 17, 0, },
> + { HI3519_SPI2_CLK, "clk_spi2", "50m",
> + CLK_SET_RATE_PARENT, 0xe4, 18, 0, },
> +};
> +
> +static void __init hi3519_clk_init(struct device_node *np)
> +{
> + struct hisi_clock_data *clk_data;
> +
> + clk_data = hisi_clk_init(np, HI3519_NR_CLKS);
> + if (!clk_data)
> + return;
> +
> + hisi_reset_init(np, HI3519_NR_RSTS);
> +
> + hisi_clk_register_fixed_rate(hi3519_fixed_rate_clks,
> + ARRAY_SIZE(hi3519_fixed_rate_clks),
> + clk_data);
> + hisi_clk_register_mux(hi3519_mux_clks, ARRAY_SIZE(hi3519_mux_clks),
> + clk_data);
> + hisi_clk_register_gate(hi3519_gate_clks,
> + ARRAY_SIZE(hi3519_gate_clks), clk_data);
> +}
> +
> +CLK_OF_DECLARE(hi3519_clk, "hisilicon,hi3519-crg", hi3519_clk_init);
> diff --git a/drivers/clk/hisilicon/reset.c b/drivers/clk/hisilicon/reset.c
> new file mode 100644
> index 0000000..cf5c32a
> --- /dev/null
> +++ b/drivers/clk/hisilicon/reset.c
> @@ -0,0 +1,149 @@
> +/*
> + * Hisilicon Reset Controller driver
> + *
> + * Copyright (c) 2015 HiSilicon Technologies Co., Ltd.
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset-controller.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/types.h>
> +
> +#define HISI_RESET_BIT_SHIFT 0
> +#define HISI_RESET_BIT_WIDTH 16
> +#define HISI_RESET_OFFSET_SHIFT 16
> +#define HISI_RESET_OFFSET_WIDTH 16

Maybe use #define HISI_RESET_OFFSET_MASK 0xffff0000 ?
instead? Then you wouldn't need the (BIT(width)-1) dance below.

> +
> +struct hisi_reset_controller {
> + spinlock_t lock;
> + void __iomem *membase;
> + struct reset_controller_dev rcdev;
> +};
> +
> +
> +#define to_hisi_reset_controller(rcdev) \
> + container_of(rcdev, struct hisi_reset_controller, rcdev)
> +
> +/*31 16 0
> + * |---reset_spec->args[0]---|---reset_spec->args[1]---|
> + * |-------reg_offset--------|--------reg_bit----------|
> + */

Note that the return value of of_xlate is signed, so BIT(31) has to be
reserved for the sign bit. This is not going to be a problem in
practice, but since you already calculate args[0] & offset_mask, you
might as well make sure that BIT(31) is clear in the non-error case.

> +static int hisi_reset_of_xlate(struct reset_controller_dev *rcdev,
> + const struct of_phandle_args *reset_spec)
> +{
> + unsigned int offset, bit, id;
> + const __be32 *addr;
> + u64 size;
> +
> + if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
> + return -EINVAL;
> +
> + addr = of_get_address(rcdev->of_node, 0, &size, NULL);
> + if (!addr)
> + return -EINVAL;

Why is this check needed?

> + if (reset_spec->args[1] >= 32
> + || reset_spec->args[0] + reset_spec->args[1] / 8 > size)
> + return -EINVAL;
> +
> + offset = reset_spec->args[0] & (BIT(HISI_RESET_OFFSET_WIDTH) - 1);
> + bit = (reset_spec->args[1] & (BIT(HISI_RESET_BIT_WIDTH) - 1));
> + id = offset << HISI_RESET_OFFSET_SHIFT | bit;
> +
> + return id;
> +}
> +
> +static int hisi_reset_assert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct hisi_reset_controller *rstc = to_hisi_reset_controller(rcdev);
> + unsigned int offset, bit;
> + unsigned long flags;
> + u32 reg;
> +
> + offset = id >> HISI_RESET_OFFSET_SHIFT;
> + offset &= (BIT(HISI_RESET_OFFSET_WIDTH) - 1);
> + bit = id & (BIT(HISI_RESET_BIT_WIDTH) - 1);
> +
> + spin_lock_irqsave(&rstc->lock, flags);
> +
> + reg = readl(rstc->membase + offset);
> + writel(reg | BIT(bit), rstc->membase + offset);
> +
> + spin_unlock_irqrestore(&rstc->lock, flags);
> +
> + return 0;
> +}
> +
> +static int hisi_reset_deassert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct hisi_reset_controller *rstc = to_hisi_reset_controller(rcdev);
> + unsigned int offset, bit;
> + unsigned long flags;
> + u32 reg;
> +
> + offset = id >> HISI_RESET_OFFSET_SHIFT;
> + offset &= (BIT(HISI_RESET_OFFSET_WIDTH) - 1);
> + bit = id & (BIT(HISI_RESET_BIT_WIDTH) - 1);
> +
> + spin_lock_irqsave(&rstc->lock, flags);
> +
> + reg = readl(rstc->membase + offset);
> + writel(reg & ~BIT(bit), rstc->membase + offset);
> +
> + spin_unlock_irqrestore(&rstc->lock, flags);
> +
> + return 0;
> +}
> +
> +static struct reset_control_ops hisi_reset_ops = {
> + .assert = hisi_reset_assert,
> + .deassert = hisi_reset_deassert,
> +};
> +
> +int __init hisi_reset_init(struct device_node *np,
> + int nr_rsts)
> +{
> + struct hisi_reset_controller *rstc;
> +
> + rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
> + if (!rstc)
> + return -ENOMEM;
> +
> + rstc->membase = of_iomap(np, 0);
> + if (!rstc->membase)
> + return -EINVAL;
> +
> + spin_lock_init(&rstc->lock);
> +
> + rstc->rcdev.owner = THIS_MODULE;
> + rstc->rcdev.nr_resets = nr_rsts;

nr_resets is only used by of_reset_simple_xlate to check whether a given
id is valid. This check obviously doesn't help if your ids are sparse,
so nr_resets serves no purpose if you don't use it in
hisi_reset_of_xlate. Other drivers have set this to the max id plus one,
for example sunxi or zynq.

> + rstc->rcdev.ops = &hisi_reset_ops;
> + rstc->rcdev.of_node = np;
> + rstc->rcdev.of_reset_n_cells = 2;
> + rstc->rcdev.of_xlate = hisi_reset_of_xlate;
> +
> + return reset_controller_register(&rstc->rcdev);
> +}
[...]

regards
Philipp

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