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Message-ID: <20150804062746.GA9112@leoy-linaro>
Date: Tue, 4 Aug 2015 14:27:46 +0800
From: Leo Yan <leo.yan@...aro.org>
To: Stephen Boyd <sboyd@...eaurora.org>
Cc: Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Michael Turquette <mturquette@...libre.com>,
Wei Xu <xuwei5@...ilicon.com>,
Haojian Zhuang <haojian.zhuang@...aro.org>,
Bintian Wang <bintian.wang@...wei.com>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org,
Guodong Xu <guodong.xu@...aro.org>,
Jian Zhang <zhangjian001@...ilicon.com>,
Zhenwei Wang <Zhenwei.wang@...ilicon.com>,
Haoju Mo <mohaoju@...ilicon.com>,
Dan Zhao <dan.zhao@...ilicon.com>, sunzhaosheng@...ilicon.com,
victor.lixin@...ilicon.com
Subject: Re: [PATCH v3 4/5] clk: Hi6220: add stub clock driver
Hi Stephen,
On Mon, Aug 03, 2015 at 02:37:52PM -0700, Stephen Boyd wrote:
> On 08/03, Leo Yan wrote:
> > diff --git a/drivers/clk/hisilicon/clk-hi6220-stub.c b/drivers/clk/hisilicon/clk-hi6220-stub.c
> > new file mode 100644
> > index 0000000..0931666
> > --- /dev/null
> > +++ b/drivers/clk/hisilicon/clk-hi6220-stub.c
> > @@ -0,0 +1,279 @@
> > +/*
> > + * Hi6220 stub clock driver
> > + *
> > + * Copyright (c) 2015 Hisilicon Limited.
> > + * Copyright (c) 2015 Linaro Limited.
> > + *
> > + * Author: Leo Yan <leo.yan@...aro.org>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + *
> > + */
> > +
> > +#include <linux/clkdev.h>
>
> Is this include used?
>
> > +#include <linux/clk-provider.h>
> > +#include <linux/clk.h>
>
> Is this include used?
>
> > +#include <linux/err.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/mailbox_client.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/slab.h>
> > +#include <linux/kernel.h>
> > +
> > +#include <dt-bindings/clock/hi6220-clock.h>
> > +
> > +/* Stub clocks id */
> > +#define HI6220_STUB_ACPU0 0
> > +#define HI6220_STUB_ACPU1 1
> > +#define HI6220_STUB_GPU 2
> > +#define HI6220_STUB_DDR 5
> > +
> > +/* Mailbox message */
> > +#define HI6220_MBOX_MSG_LEN 8
> > +
> > +#define HI6220_MBOX_FREQ (0xA)
> > +#define HI6220_MBOX_CMD_SET (0x3)
> > +#define HI6220_MBOX_OBJ_AP (0x0)
> > +
> > +/* CPU dynamic frequency scaling */
> > +#define ACPU_DFS_FREQ_MAX (0x1724)
> > +#define ACPU_DFS_CUR_FREQ (0x17CC)
> > +#define ACPU_DFS_FLAG (0x1B30)
> > +#define ACPU_DFS_FREQ_REQ (0x1B34)
> > +#define ACPU_DFS_FREQ_LMT (0x1B38)
> > +#define ACPU_DFS_LOCK_FLAG (0xAEAEAEAE)
>
> We don't need parenthesis around single values in these macros.
>
> > +
> > +#define to_stub_clk(hw) container_of(hw, struct hi6220_stub_clk, hw)
> > +
> > +struct hi6220_stub_clk {
> > + u32 id;
> > + u32 rate;
> > +
> > + struct device *dev;
> > + struct clk_hw hw;
> > +
> > + struct regmap *dfs_map;
> > + struct mbox_client cl;
> > + struct mbox_chan *mbox;
> > +};
> > +
> > +struct hi6220_mbox_msg {
> > + unsigned char type;
> > + unsigned char cmd;
> > + unsigned char obj;
> > + unsigned char src;
> > + unsigned char para[4];
> > +};
> > +
> > +union hi6220_mbox_data {
> > + unsigned int data[HI6220_MBOX_MSG_LEN];
> > + struct hi6220_mbox_msg msg;
> > +};
> > +
> > +static unsigned int hi6220_acpu_get_freq(struct hi6220_stub_clk *stub_clk)
> > +{
> > + unsigned int freq;
> > +
> > + regmap_read(stub_clk->dfs_map, ACPU_DFS_CUR_FREQ, &freq);
> > + return freq;
> > +}
> > +
> > +static int hi6220_acpu_set_freq(struct hi6220_stub_clk *stub_clk,
> > + unsigned int freq)
> > +{
> > + union hi6220_mbox_data data;
> > +
> > + stub_clk->mbox = mbox_request_channel(&stub_clk->cl, 0);
>
> Why not request the channel once in probe?
>
> > + if (IS_ERR(stub_clk->mbox)) {
> > + dev_err(stub_clk->dev, "failed get mailbox channel\n");
> > + return PTR_ERR(stub_clk->mbox);
> > + };
> > +
> > + /* set the frequency in sram */
> > + regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, freq);
> > +
> > + /* compound mailbox message */
> > + data.msg.type = HI6220_MBOX_FREQ;
> > + data.msg.cmd = HI6220_MBOX_CMD_SET;
> > + data.msg.obj = HI6220_MBOX_OBJ_AP;
> > + data.msg.src = HI6220_MBOX_OBJ_AP;
> > +
> > + mbox_send_message(stub_clk->mbox, &data);
> > + mbox_free_channel(stub_clk->mbox);
> > + return 0;
> > +}
> > +
> > +static int hi6220_acpu_round_freq(struct hi6220_stub_clk *stub_clk,
> > + unsigned int freq)
> > +{
> > + unsigned int limit_flag, limit_freq = UINT_MAX;
> > + unsigned int max_freq;
> > +
> > + /* check the constrainted frequency */
>
> s/constrainted/constrained/ ?
>
> > + regmap_read(stub_clk->dfs_map, ACPU_DFS_FLAG, &limit_flag);
> > + if (limit_flag == ACPU_DFS_LOCK_FLAG)
> > + regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, &limit_freq);
> > +
> > + /* check the supported maximum frequency */
> > + regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_MAX, &max_freq);
> > +
> > + /* calculate the real maximum frequency */
> > + max_freq = min(max_freq, limit_freq);
> > +
> > + if (WARN_ON(freq > max_freq))
> > + freq = max_freq;
> > +
> > + return freq;
> > +}
> > +
> > +static unsigned long hi6220_stub_clk_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + u32 rate = 0;
> > + struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
> > +
> > + switch (stub_clk->id) {
> > + case HI6220_STUB_ACPU0:
> > + rate = hi6220_acpu_get_freq(stub_clk);
> > +
> > + /* convert from KHz to Hz */
>
> s/KHz/kHz/ ?
>
> > + rate *= 1000;
> > + break;
> > +
> > + default:
> > + dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
> > + __func__, stub_clk->id);
> > + break;
> > + }
> > +
> > + return rate;
> > +}
> > +
> > +static int hi6220_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> > + unsigned long parent_rate)
> > +{
> > + struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
> > + unsigned long new_rate = rate / 1000; /* Khz */
>
> s/KHz/kHz/ ?
>
> > + int ret = 0;
> > +
> > + switch (stub_clk->id) {
> > + case HI6220_STUB_ACPU0:
> > + ret = hi6220_acpu_set_freq(stub_clk, new_rate);
> > + if (ret < 0)
> > + return ret;
> > +
> > + break;
> > +
> > + default:
> > + dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
> > + __func__, stub_clk->id);
> > + break;
> > + }
> > +
> > + stub_clk->rate = new_rate;
>
> Why do we store away the rate? Is this used anywhere?
>
> > +
> > + pr_debug("%s: set rate=%ldKhz\n", __func__, new_rate);
> > + return ret;
> > +}
> > +
> > +static long hi6220_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> > + unsigned long *parent_rate)
> > +{
> > + struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
> > + unsigned long new_rate = rate / 1000; /* Khz */
>
> s/KHz/kHz/ ?
>
> > +
> > + switch (stub_clk->id) {
> > + case HI6220_STUB_ACPU0:
> > + new_rate = hi6220_acpu_round_freq(stub_clk, new_rate);
> > +
> > + /* convert from KHz to Hz */
>
> s/KHz/kHz/ ?
>
> > + new_rate *= 1000;
> > + break;
> > +
> > + default:
> > + dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
> > + __func__, stub_clk->id);
> > + break;
> > + }
> > +
> > + return new_rate;
> > +}
> > +
> > +static struct clk_ops hi6220_stub_clk_ops = {
>
> const?
>
> > + .recalc_rate = hi6220_stub_clk_recalc_rate,
> > + .round_rate = hi6220_stub_clk_round_rate,
> > + .set_rate = hi6220_stub_clk_set_rate,
> > +};
> > +
> > +static int hi6220_stub_clk_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct clk_init_data init;
> > + struct hi6220_stub_clk *stub_clk;
> > + struct clk *clk;
> > + struct device_node *np = pdev->dev.of_node;
> > +
> > + stub_clk = devm_kzalloc(&pdev->dev, sizeof(*stub_clk), GFP_KERNEL);
>
> just use dev?
>
> > + if (!stub_clk)
> > + return -ENOMEM;
> > +
> > + stub_clk->dfs_map = syscon_regmap_lookup_by_phandle(np,
> > + "hisilicon,hi6220-clk-sram");
> > + if (IS_ERR(stub_clk->dfs_map)) {
> > + dev_err(dev, "failed to get sram regmap\n");
> > + return PTR_ERR(stub_clk->dfs_map);
> > + }
> > +
> > + stub_clk->hw.init = &init;
> > + stub_clk->dev = dev;
> > + stub_clk->id = HI6220_STUB_ACPU0;
> > +
> > + /* Use mailbox client with blocking mode */
> > + stub_clk->cl.dev = &pdev->dev;
>
> just use dev?
>
> > + stub_clk->cl.tx_done = NULL;
> > + stub_clk->cl.tx_block = true;
> > + stub_clk->cl.tx_tout = 500;
> > + stub_clk->cl.knows_txdone = false;
> > +
> > + init.name = "acpu0";
> > + init.ops = &hi6220_stub_clk_ops;
> > + init.num_parents = 0;
> > + init.flags = CLK_IS_ROOT;
> > +
> > + clk = clk_register(NULL, &stub_clk->hw);
>
> why not devm_clk_register?
>
> > + if (IS_ERR(clk))
> > + return PTR_ERR(clk);
> > +
> > + of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
>
> And check this for an error return value? Also, just use dev?
>
> > +
> > + /* initialize buffer to zero */
> > + regmap_write(stub_clk->dfs_map, ACPU_DFS_FLAG, 0x0);
> > + regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, 0x0);
> > + regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, 0x0);
> > +
> > + dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
>
> just use dev?
>
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id hi6220_stub_clk_of_match[] = {
> > + { .compatible = "hisilicon,hi6220-stub-clk", },
> > + {}
> > +};
> > +
> > +static struct platform_driver hi6220_stub_clk_driver = {
> > + .driver = {
> > + .name = "hi6220-stub-clk",
> > + .of_match_table = of_match_ptr(hi6220_stub_clk_of_match),
>
> We can leave off of_match_ptr() here.
>
> > + },
> > + .probe = hi6220_stub_clk_probe,
> > +};
Thanks for review; Accept all comments and will refine for them :)
Thanks,
Leo Yan
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