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Message-ID: <20220411090015.6290b0b0@xps13>
Date: Mon, 11 Apr 2022 09:00:15 +0200
From: Miquel Raynal <miquel.raynal@...tlin.com>
To: Liang Yang <liang.yang@...ogic.com>
Cc: <linux-mtd@...ts.infradead.org>, Rob Herring <robh+dt@...nel.org>,
Richard Weinberger <richard@....at>,
Vignesh Raghavendra <vigneshr@...com>,
Jerome Brunet <jbrunet@...libre.com>,
Neil Armstrong <narmstrong@...libre.com>,
Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
Kevin Hilman <khilman@...libre.com>,
Jianxin Pan <jianxin.pan@...ogic.com>,
Victor Wan <victor.wan@...ogic.com>,
XianWei Zhao <xianwei.zhao@...ogic.com>,
Kelvin Zhang <kelvin.zhang@...ogic.com>,
BiChao Zheng <bichao.zheng@...ogic.com>,
YongHui Yu <yonghui.yu@...ogic.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-amlogic@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>
Subject: Re: [PATCH v4 1/2] mtd: rawnand: meson: discard the common MMC sub
clock framework
Hi Liang,
liang.yang@...ogic.com wrote on Mon, 11 Apr 2022 10:40:15 +0800:
> Hi Miquel,
>
> On 2022/4/4 16:30, Miquel Raynal wrote:
> > [ EXTERNAL EMAIL ]
> >
> > Hi Liang,
> >
> > liang.yang@...ogic.com wrote on Sat, 2 Apr 2022 15:49:19 +0800:
> >
> >> EMMC and NAND have the same clock control register named 'SD_EMMC_CLOCK' which is
> >> defined in EMMC port internally. bit0~5 of 'SD_EMMC_CLOCK' is the divider and
> >> bit6~7 is the mux for fix pll and xtal.A common MMC and NAND sub-clock has been
> >> implemented and can be used by the eMMC and NAND controller (which are mutually
> >> exclusive anyway). Let's use this new clock.
> >>
> >> Signed-off-by: Liang Yang <liang.yang@...ogic.com>
> >> ---
> >> drivers/mtd/nand/raw/meson_nand.c | 89 +++++++++++++++----------------
> >> 1 file changed, 42 insertions(+), 47 deletions(-)
> >>
> >> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> >> index ac3be92872d0..1b1a9407fb2f 100644
> >> --- a/drivers/mtd/nand/raw/meson_nand.c
> >> +++ b/drivers/mtd/nand/raw/meson_nand.c
> >> @@ -10,6 +10,7 @@
> >> #include <linux/dma-mapping.h>
> >> #include <linux/interrupt.h>
> >> #include <linux/clk.h>
> >> +#include <linux/clk-provider.h>
> >> #include <linux/mtd/rawnand.h>
> >> #include <linux/mtd/mtd.h>
> >> #include <linux/mfd/syscon.h>
> >> @@ -19,6 +20,7 @@
> >> #include <linux/iopoll.h>
> >> #include <linux/of.h>
> >> #include <linux/of_device.h>
> >> +#include <linux/of_address.h>
> >> #include <linux/sched/task_stack.h>
> >> >> #define NFC_REG_CMD 0x00
> >> @@ -104,6 +106,9 @@
> >> >> #define PER_INFO_BYTE 8
> >> >> +#define CLK_DIV_SHIFT 0
> >> +#define CLK_DIV_WIDTH 6
> >> +
> >> struct meson_nfc_nand_chip {
> >> struct list_head node;
> >> struct nand_chip nand;
> >> @@ -151,15 +156,15 @@ struct meson_nfc {
> >> struct nand_controller controller;
> >> struct clk *core_clk;
> >> struct clk *device_clk;
> >> - struct clk *phase_tx;
> >> - struct clk *phase_rx;
> >> + struct clk *nand_clk;
> >> + struct clk_divider nand_divider;
> >> >> unsigned long clk_rate;
> >> u32 bus_timing;
> >> >> struct device *dev;
> >> void __iomem *reg_base;
> >> - struct regmap *reg_clk;
> >> + void __iomem *sd_emmc_clock;
> >> struct completion completion;
> >> struct list_head chips;
> >> const struct meson_nfc_data *data;
> >> @@ -235,7 +240,7 @@ static void meson_nfc_select_chip(struct nand_chip *nand, int chip)
> >> nfc->timing.tbers_max = meson_chip->tbers_max;
> >> >> if (nfc->clk_rate != meson_chip->clk_rate) {
> >> - ret = clk_set_rate(nfc->device_clk, meson_chip->clk_rate);
> >> + ret = clk_set_rate(nfc->nand_clk, meson_chip->clk_rate);
> >> if (ret) {
> >> dev_err(nfc->dev, "failed to set clock rate\n");
> >> return;
> >> @@ -406,7 +411,6 @@ static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms)
> >> cmd = NFC_CMD_RB | NFC_CMD_RB_INT
> >> | nfc->param.chip_select | nfc->timing.tbers_max;
> >> writel(cmd, nfc->reg_base + NFC_REG_CMD);
> >> -
> >
> > Please avoid these spacing changes in the middle of a commit.
>
> ok, i will fix it.
> >
> >> ret = wait_for_completion_timeout(&nfc->completion,
> >> msecs_to_jiffies(timeout_ms));
> >> if (ret == 0)
> >> @@ -985,9 +989,11 @@ static const struct mtd_ooblayout_ops meson_ooblayout_ops = {
> >> .free = meson_ooblayout_free,
> >> };
> >> >> +struct clk_parent_data nfc_divider_parent_data[1];
> >> static int meson_nfc_clk_init(struct meson_nfc *nfc)
> >> {
> >> int ret;
> >> + struct clk_init_data init = {0};
> >> >> /* request core clock */
> >> nfc->core_clk = devm_clk_get(nfc->dev, "core");
> >> @@ -1002,21 +1008,26 @@ static int meson_nfc_clk_init(struct meson_nfc *nfc)
> >> return PTR_ERR(nfc->device_clk);
> >> }
> >> >> - nfc->phase_tx = devm_clk_get(nfc->dev, "tx");
> >> - if (IS_ERR(nfc->phase_tx)) {
> >> - dev_err(nfc->dev, "failed to get TX clk\n");
> >> - return PTR_ERR(nfc->phase_tx);
> >> - }
> >> -
> >> - nfc->phase_rx = devm_clk_get(nfc->dev, "rx");
> >> - if (IS_ERR(nfc->phase_rx)) {
> >> - dev_err(nfc->dev, "failed to get RX clk\n");
> >> - return PTR_ERR(nfc->phase_rx);
> >> - }
> >> + init.name = devm_kstrdup(nfc->dev, "nfc#div", GFP_KERNEL);
> >> + init.ops = &clk_divider_ops;
> >> + nfc_divider_parent_data[0].fw_name = "device";
> >> + init.parent_data = nfc_divider_parent_data;
> >> + init.num_parents = 1;
> >> + nfc->nand_divider.reg = nfc->sd_emmc_clock;
> >> + nfc->nand_divider.shift = CLK_DIV_SHIFT;
> >> + nfc->nand_divider.width = CLK_DIV_WIDTH;
> >> + nfc->nand_divider.hw.init = &init;
> >> + nfc->nand_divider.flags = CLK_DIVIDER_ONE_BASED |
> >> + CLK_DIVIDER_ROUND_CLOSEST |
> >> + CLK_DIVIDER_ALLOW_ZERO;
> >> +
> >> + nfc->nand_clk = devm_clk_register(nfc->dev, &nfc->nand_divider.hw);
> >> + if (IS_ERR(nfc->nand_clk))
> >> + return PTR_ERR(nfc->nand_clk);
> >> >> /* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
> >> - regmap_update_bits(nfc->reg_clk,
> >> - 0, CLK_SELECT_NAND, CLK_SELECT_NAND);
> >> + writel(CLK_SELECT_NAND | readl(nfc->sd_emmc_clock),
> >> + nfc->sd_emmc_clock);
> >> >> ret = clk_prepare_enable(nfc->core_clk);
> >> if (ret) {
> >> @@ -1030,29 +1041,21 @@ static int meson_nfc_clk_init(struct meson_nfc *nfc)
> >> goto err_device_clk;
> >> }
> >> >> - ret = clk_prepare_enable(nfc->phase_tx);
> >> + ret = clk_prepare_enable(nfc->nand_clk);
> >> if (ret) {
> >> - dev_err(nfc->dev, "failed to enable TX clock\n");
> >> - goto err_phase_tx;
> >> + dev_err(nfc->dev, "pre enable NFC divider fail\n");
> >> + goto err_nand_clk;
> >> }
> >> >> - ret = clk_prepare_enable(nfc->phase_rx);
> >> - if (ret) {
> >> - dev_err(nfc->dev, "failed to enable RX clock\n");
> >> - goto err_phase_rx;
> >> - }
> >> -
> >> - ret = clk_set_rate(nfc->device_clk, 24000000);
> >> + ret = clk_set_rate(nfc->nand_clk, 24000000);
> >
> > Is this rename really useful?
>
> yes, it works.
I understand it works, but if this is just a name change of a variable
in your driver that has implications everywhere in this driver, then
it's probably best to do it in a separate commit to ease the review.
>
> >
> >> if (ret)
> >> - goto err_disable_rx;
> >> + goto err_disable_clk;
> >> >> return 0;
> >> >> -err_disable_rx:
> >> - clk_disable_unprepare(nfc->phase_rx);
> >> -err_phase_rx:
> >> - clk_disable_unprepare(nfc->phase_tx);
> >> -err_phase_tx:
> >> +err_disable_clk:
> >> + clk_disable_unprepare(nfc->nand_clk);
> >> +err_nand_clk:
> >> clk_disable_unprepare(nfc->device_clk);
> >> err_device_clk:
> >> clk_disable_unprepare(nfc->core_clk);
> >> @@ -1061,8 +1064,7 @@ static int meson_nfc_clk_init(struct meson_nfc *nfc)
> >> >> static void meson_nfc_disable_clk(struct meson_nfc *nfc)
> >> {
> >> - clk_disable_unprepare(nfc->phase_rx);
> >> - clk_disable_unprepare(nfc->phase_tx);
> >> + clk_disable_unprepare(nfc->nand_clk);
> >> clk_disable_unprepare(nfc->device_clk);
> >> clk_disable_unprepare(nfc->core_clk);
> >> }
> >> @@ -1374,7 +1376,6 @@ static int meson_nfc_probe(struct platform_device *pdev)
> >> {
> >> struct device *dev = &pdev->dev;
> >> struct meson_nfc *nfc;
> >> - struct resource *res;
> >> int ret, irq;
> >> >> nfc = devm_kzalloc(dev, sizeof(*nfc), GFP_KERNEL);
> >> @@ -1388,21 +1389,15 @@ static int meson_nfc_probe(struct platform_device *pdev)
> >> nand_controller_init(&nfc->controller);
> >> INIT_LIST_HEAD(&nfc->chips);
> >> init_completion(&nfc->completion);
> >> -
> >
> > Please don't modify spacing in this commit.
> >ok
>
> >> nfc->dev = dev;
> >> >> - res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >> - nfc->reg_base = devm_ioremap_resource(dev, res);
> >> + nfc->reg_base = devm_platform_ioremap_resource_byname(pdev, "nfc");
> >
> > This change seems unrelated.
>
> To be consistent with the following devm_platform_ioremap_resource_byname(pdev, "emmc"). do you mean that we don't need it?>
So indeed it should not be in this commit. You can do that as a
preparation patch if you wish.
> >> if (IS_ERR(nfc->reg_base))
> >> return PTR_ERR(nfc->reg_base);
> >> >> - nfc->reg_clk =
> >> - syscon_regmap_lookup_by_phandle(dev->of_node,
> >> - "amlogic,mmc-syscon");
> >> - if (IS_ERR(nfc->reg_clk)) {
> >> - dev_err(dev, "Failed to lookup clock base\n");
> >> - return PTR_ERR(nfc->reg_clk);
> >> - }
> >> + nfc->sd_emmc_clock = devm_platform_ioremap_resource_byname(pdev, "emmc");
> >> + if (IS_ERR(nfc->sd_emmc_clock))
> >> + return PTR_ERR(nfc->sd_emmc_clock);
> >
> > While I agree this is much better than the previous solution, we cannot
> > break DT compatibility, so you need to try getting the emmc clock, but
> > if it fails you should fallback to the regmap lookup.
>
> ok, i will fix it next version. thanks.
>
> >
> >> >> irq = platform_get_irq(pdev, 0);
> >> if (irq < 0)
> >
> >
> > Thanks,
> > Miquèl
> >
> > .
Thanks,
Miquèl
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