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Date: Fri, 30 Nov 2018 00:31:38 -0800
From: Stephen Boyd <sboyd@...nel.org>
To: Sugaya Taichi <sugaya.taichi@...ionext.com>,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-serial@...r.kernel.org
Cc: Michael Turquette <mturquette@...libre.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Russell King <linux@...linux.org.uk>,
Jiri Slaby <jslaby@...e.com>,
Masami Hiramatsu <masami.hiramatsu@...aro.org>,
Jassi Brar <jaswinder.singh@...aro.org>,
Sugaya Taichi <sugaya.taichi@...ionext.com>
Subject: Re: [PATCH 07/14] clock: milbeaut: Add Milbeaut M10V clock control
Quoting Sugaya Taichi (2018-11-18 17:01:12)
> Add Milbeaut M10V clock ( including PLL ) control.
Please give some more details here.
>
> Signed-off-by: Sugaya Taichi <sugaya.taichi@...ionext.com>
> ---
> drivers/clk/Makefile | 1 +
> drivers/clk/clk-m10v.c | 671 +++++++++++++++++++++++++++++++++++++++++++++++++
And this is different from Uniphier? Maybe we need a socionext
directory under drivers/clk/.
> 2 files changed, 672 insertions(+)
> create mode 100644 drivers/clk/clk-m10v.c
>
> diff --git a/drivers/clk/clk-m10v.c b/drivers/clk/clk-m10v.c
> new file mode 100644
> index 0000000..aa92a69
> --- /dev/null
> +++ b/drivers/clk/clk-m10v.c
> @@ -0,0 +1,671 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2018 Socionext Inc.
> + * Copyright (C) 2016 Linaro Ltd.
> + *
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
Is this include used?
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/of_address.h>
> +#include <linux/of.h>
> +#include <linux/spinlock.h>
> +
> +#define CLKSEL1 0x0
> +#define CLKSEL(n) (((n) - 1) * 4 + CLKSEL1)
> +
> +#define PLLCNT1 0x30
> +#define PLLCNT(n) (((n) - 1) * 4 + PLLCNT1)
> +
> +#define CLKSTOP1 0x54
> +#define CLKSTOP(n) (((n) - 1) * 4 + CLKSTOP1)
> +
> +#define CRSWR 0x8c
> +#define CRRRS 0x90
> +#define CRRSM 0x94
> +
> +#define to_m10v_mux(_hw) container_of(_hw, struct m10v_mux, hw)
> +#define to_m10v_gate(_hw) container_of(_hw, struct m10v_gate, hw)
> +#define to_m10v_div(_hw) container_of(_hw, struct m10v_div, hw)
> +#define to_m10v_pll(_hw) container_of(_hw, struct m10v_pll, hw)
> +
> +static void __iomem *clk_base;
> +static struct device_node *np_top;
> +static DEFINE_SPINLOCK(crglock);
Please make more specific names for these global variables by prefixing
with m10v_. Also consider getting rid of the iomem and np_top globals
entirely and associate those with clks differently.
> +
> +static __init void __iomem *m10v_clk_iomap(void)
> +{
> + if (clk_base)
> + return clk_base;
> +
> + np_top = of_find_compatible_node(NULL, NULL,
> + "socionext,milbeaut-m10v-clk-regs");
> + if (!np_top) {
> + pr_err("%s: CLK iomap failed!\n", __func__);
We haven't iomapped yet though.
> + return NULL;
> + }
> +
> + clk_base = of_iomap(np_top, 0);
> + of_node_put(np_top);
Would be nicer to use platform_device APIs instead of OF ones.
> +
> + return clk_base;
> +}
> +
> +struct m10v_mux {
> + struct clk_hw hw;
> + const char *cname;
> + u32 parent;
> +};
> +
> +static u8 m10v_mux_get_parent(struct clk_hw *hw)
> +{
> + struct m10v_mux *mcm = to_m10v_mux(hw);
> + struct clk_hw *parent;
> + int i;
> +
> + i = clk_hw_get_num_parents(hw);
> + while (i--) {
> + parent = clk_hw_get_parent_by_index(hw, i);
> + if (clk_hw_get_rate(parent))
> + break;
> + }
> +
> + if (i < 0) {
> + pr_info("%s:%s no parent?!\n",
> + __func__, mcm->cname);
> + i = 0;
> + }
> +
> + return i;
> +}
> +
> +static int m10v_mux_set_parent(struct clk_hw *hw, u8 index)
> +{
> + struct m10v_mux *mcm = to_m10v_mux(hw);
> +
> + mcm->parent = index;
> + return 0;
> +}
> +
> +static const struct clk_ops m10v_mux_ops = {
> + .get_parent = m10v_mux_get_parent,
> + .set_parent = m10v_mux_set_parent,
> + .determine_rate = __clk_mux_determine_rate,
> +};
> +
> +void __init m10v_clk_mux_setup(struct device_node *node)
> +{
> + const char *clk_name = node->name;
> + struct clk_init_data init;
> + const char **parent_names;
> + struct m10v_mux *mcm;
> + struct clk *clk;
> + int i, parents;
> +
> + if (!m10v_clk_iomap())
> + return;
> +
> + of_property_read_string(node, "clock-output-names", &clk_name);
> +
> + parents = of_clk_get_parent_count(node);
> + if (parents < 2) {
> + pr_err("%s: not a mux\n", clk_name);
How is this possible?
> + return;
> + }
> +
> + parent_names = kzalloc((sizeof(char *) * parents), GFP_KERNEL);
> + if (!parent_names)
> + return;
> +
> + for (i = 0; i < parents; i++)
> + parent_names[i] = of_clk_get_parent_name(node, i);
This is of_clk_parent_fill().
> +
> + mcm = kzalloc(sizeof(*mcm), GFP_KERNEL);
> + if (!mcm)
> + goto err_mcm;
> +
> + init.name = clk_name;
> + init.ops = &m10v_mux_ops;
> + init.flags = CLK_IS_BASIC | CLK_SET_RATE_PARENT;
Please don't use CLK_IS_BASIC unless you need it.
> + init.num_parents = parents;
> + init.parent_names = parent_names;
> +
> + mcm->cname = clk_name;
> + mcm->parent = 0;
> + mcm->hw.init = &init;
> +
> + clk = clk_register(NULL, &mcm->hw);
> + if (IS_ERR(clk))
> + goto err_clk;
> +
> + of_clk_add_provider(node, of_clk_src_simple_get, clk);
> + return;
> +
> +err_clk:
> + kfree(mcm);
> +err_mcm:
> + kfree(parent_names);
> +}
> +CLK_OF_DECLARE(m10v_clk_mux, "socionext,milbeaut-m10v-clk-mux",
> + m10v_clk_mux_setup);
Any chance you can use a platform driver?
> +
> +struct m10v_pll {
> + struct clk_hw hw;
> + const char *cname;
> + const struct clk_ops ops;
> + u32 offset;
> + u32 div, mult;
> + bool ro;
> +};
> +
> +#define ST 1
> +#define SEL 2
> +
> +static void _mpg_enable(struct clk_hw *hw, unsigned int enable)
> +{
> + struct m10v_pll *mpg = to_m10v_pll(hw);
> + unsigned long flags;
> + u32 val;
> +
> + if (mpg->ro) {
> + pr_debug("%s:%d %s: read-only\n",
> + __func__, __LINE__, mpg->cname);
> + return;
> + }
> +
> + spin_lock_irqsave(&crglock, flags);
> +
> + val = readl(clk_base + PLLCNT(SEL));
> + if (enable)
> + val |= BIT(mpg->offset);
> + else
> + val &= ~BIT(mpg->offset);
> + writel(val, clk_base + PLLCNT(SEL));
> +
> + spin_unlock_irqrestore(&crglock, flags);
> +}
> +
> +static int mpg_enable(struct clk_hw *hw)
> +{
> + _mpg_enable(hw, 1);
> + return 0;
> +}
> +
> +static void mpg_disable(struct clk_hw *hw)
> +{
> + _mpg_enable(hw, 0);
> +}
> +
> +static int mpg_is_enabled(struct clk_hw *hw)
> +{
> + struct m10v_pll *mpg = to_m10v_pll(hw);
> +
> + return readl(clk_base + PLLCNT(SEL)) & (1 << mpg->offset);
> +}
> +
> +static void _mpg_prepare(struct clk_hw *hw, unsigned int on)
> +{
> + struct m10v_pll *mpg = to_m10v_pll(hw);
> + unsigned long flags;
> + u32 val;
> +
> + if (mpg->ro) {
Should have different RO ops for read-only clks.
> + pr_debug("%s:%d %s: read-only\n",
> + __func__, __LINE__, mpg->cname);
> + return;
> + }
> +
> + val = readl(clk_base + PLLCNT(ST));
> + if (!on == !(val & BIT(mpg->offset)))
> + return;
> +
> + /* disable */
Please remove obvious comments.
> + mpg_disable(hw);
> +
> + spin_lock_irqsave(&crglock, flags);
> +
> + val = readl(clk_base + PLLCNT(ST));
> + if (on)
> + val |= BIT(mpg->offset);
> + else
> + val &= ~BIT(mpg->offset);
> + writel(val, clk_base + PLLCNT(ST));
> +
> + spin_unlock_irqrestore(&crglock, flags);
> +
> + udelay(on ? 200 : 10);
> +}
> +
> +static int mpg_prepare(struct clk_hw *hw)
> +{
> + _mpg_prepare(hw, 1);
> + return 0;
> +}
> +
> +static void mpg_unprepare(struct clk_hw *hw)
> +{
> + _mpg_prepare(hw, 0);
> +}
> +
> +static int mpg_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long prate)
> +{
Why is this implemented then?
> + return 0;
> +}
> +
> +static unsigned long mpg_recalc_rate(struct clk_hw *hw,
> + unsigned long prate)
> +{
> + struct m10v_pll *mpg = to_m10v_pll(hw);
> + unsigned long long rate = prate;
> +
> + if (mpg_is_enabled(hw)) {
> + rate = (unsigned long long)prate * mpg->mult;
> + do_div(rate, mpg->div);
> + }
> +
> + return (unsigned long)rate;
> +}
> +
> +static long mpg_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *prate)
> +{
> + struct m10v_pll *mpg = to_m10v_pll(hw);
> + unsigned long long temp_rate = (unsigned long long)*prate * mpg->mult;
> +
> + if (mpg->ro)
> + return mpg_recalc_rate(hw, *prate);
> +
> + return do_div(temp_rate, mpg->div);
There shouldn't be round_rate implemented at all if the device is
'read-only' or can't change frequency because set_rate op is empty.
> +}
> +
[..]
> +
> +static void mdc_set_div(struct m10v_div *mdc, u32 div)
> +{
> + u32 off, shift, val;
> +
> + off = mdc->offset / 32 * 4;
> + shift = mdc->offset % 32;
> +
> + val = readl(clk_base + CLKSEL1 + off);
> + val &= ~(mdc->mask << shift);
> + val |= (div << shift);
> + writel(val, clk_base + CLKSEL1 + off);
> +
> + if (mdc->waitdchreq) {
> + unsigned int count = 250;
> +
> + writel(1, clk_base + CLKSEL(11));
> +
> + do {
> + udelay(1);
> + } while (--count && readl(clk_base + CLKSEL(11)) & 1);
Use readl_poll_timeout()?
> +
> + if (!count)
> + pr_err("%s:%s CLK(%d) couldn't stabilize\n",
> + __func__, mdc->cname, mdc->offset);
> + }
> +}
> +
[...]
> +
> +void __init m10v_clk_gate_setup(struct device_node *node)
> +{
> + const char *clk_name = node->name;
> + struct clk_init_data init;
> + const char *parent_name;
> + struct m10v_gate *mgc;
> + struct clk *clk;
> + u32 offset;
> + int ret;
> +
> + if (!m10v_clk_iomap())
> + return;
> +
> + of_property_read_string(node, "clock-output-names", &clk_name);
> +
> + ret = of_property_read_u32(node, "offset", &offset);
> + if (ret) {
> + pr_err("%s: missing 'offset' property\n", clk_name);
> + return;
> + }
> +
> + parent_name = of_clk_get_parent_name(node, 0);
> +
> + mgc = kzalloc(sizeof(*mgc), GFP_KERNEL);
> + if (!mgc)
> + return;
> +
> + init.name = clk_name;
> + init.ops = &m10v_gate_ops;
> + init.flags = CLK_IS_BASIC | CLK_SET_RATE_PARENT;
> + init.parent_names = &parent_name;
> + init.num_parents = 1;
> +
> + mgc->cname = clk_name;
> + mgc->offset = offset;
> + mgc->hw.init = &init;
> + if (of_get_property(node, "read-only", NULL))
> + mgc->ro = true;
> +
> + clk = clk_register(NULL, &mgc->hw);
Please use clk_hw based registration and provider APIs.
> + if (IS_ERR(clk))
> + kfree(mgc);
> + else
> + of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +}
> +CLK_OF_DECLARE(m10v_clk_gate, "socionext,milbeaut-m10v-clk-gate",
> + m10v_clk_gate_setup);
> --
I suspect this driver will significantly change so I'm not reviewing
any further until it's sent again.
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