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Message-ID: <298cd5a5-66cf-0936-405e-59bcc7c396ed@socionext.com>
Date: Tue, 4 Dec 2018 17:26:16 +0900
From: "Sugaya, Taichi" <sugaya.taichi@...ionext.com>
To: Stephen Boyd <sboyd@...nel.org>, 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>
Subject: Re: [PATCH 07/14] clock: milbeaut: Add Milbeaut M10V clock control
Hi,
Thank you for your comments.
On 2018/11/30 17:31, Stephen Boyd wrote:
> Quoting Sugaya Taichi (2018-11-18 17:01:12)
>> Add Milbeaut M10V clock ( including PLL ) control.
>
> Please give some more details here.
OK, add more description.
>
>>
>> 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/.
Yes, M10V is a one of the Milbeaut series ( not Uniphier ).
Anyway, I will talk to Uniphier team about creating a socionext directory.
>
>> 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?
I will check and drop if they are not 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.
I got it.
>
>> +
>> +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.
Yes.
>
>> + 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.
OK, use platform_device APIs.
>
>> +
>> + 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?
When the node has more than 1 clks...
Or I am misunderstanding your question?
>
>> + 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().
OK, use it instead.
>
>> +
>> + 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.
OK, confirm 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?
OK. try to use 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.
I got it.
>
>> + 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.
Oops, OK remove.
>
>> + 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?
This is not necessary maybe. so consider whether getting rid of it.
>
>> + 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.
I understand. I will describe correctly.
>
>> +}
>> +
> [..]
>> +
>> +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()?
OK. use it instead.
>
>> +
>> + 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.
I got it. I try to describe with referring other drivers.
>
>> + 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.
I understand. I study and try to renew the driver.
>
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