Re: [PATCH] mtd: rawnand: meson: fix the clock after discarding sd_emmc_c_clkc

[Liang Yang <liang.yang@amlogic.com>]

Hi Jerome,

On 2022/1/6 16:16, Jerome Brunet wrote:
> [ EXTERNAL EMAIL ]
> 
> 
> On Thu 06 Jan 2022 at 11:25, Liang Yang <liang.yang@amlogic.com> wrote:
> 
>> Because EMMC and NAND have the same control clock register, so we
>> implement a 'sd_emmc_c_clkc'. Previously DTS is defined as below:
>>
>> 	sd_emmc_c_clkc: mmc@7000 {
>> 		compatible = "amlogic,meson-axg-mmc-clkc", "syscon";
>> 		reg = <0x0 0x7000 0x0 0x800>;
>> 	};
>>
>> 	nand-controller@7800 {
>> 		......
>>
>> 		clocks = <&clkc CLKID_SD_EMMC_C>,
>> 			<&sd_emmc_c_clkc CLKID_MMC_DIV>,
>> 			<&sd_emmc_c_clkc CLKID_MMC_PHASE_RX>,
>> 			<&sd_emmc_c_clkc CLKID_MMC_PHASE_TX>;
>> 		clock-names = "core", "device", "rx", "tx";
>> 		amlogic,mmc-syscon = <&sd_emmc_c_clkc>;
>>
>> 		......
>> 	}
>>
>> but in fact, above implementation is rejected. so now registering
>> a nand_divider.
> 
> Can you give a bit of context ? a link to the discussion rejecting this
> 
Maybe I mistake the meaning of [jianxin.pan@amlogic.com], so i need him 
to clarify it.
> As far as remember, things were getting done for A1 and stopped before
> clock part was finished. I'm saying the change is wrong, just that a
> discussion is needed before a decision is made.
>
ok.
previous discussion in this link:
https://lore.kernel.org/all/86789d73-5a6c-7729-ecd1-dcd342b2fcde@amlogic.com/
it never go on since v6.

>>
>> Change-Id: Ibeb4c7ff886f5886aac4d6c664d7bbd1b1bcb997
>> Signed-off-by: Liang Yang <liang.yang@amlogic.com>
>> ---
>>   drivers/mtd/nand/raw/meson_nand.c | 88 +++++++++++++++++--------------
>>   1 file changed, 49 insertions(+), 39 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
>> index ac3be92872d0..4472363059c2 100644
>> --- a/drivers/mtd/nand/raw/meson_nand.c
>> +++ b/drivers/mtd/nand/raw/meson_nand.c
>> @@ -2,7 +2,7 @@
>>   /*
>>    * Amlogic Meson Nand Flash Controller Driver
>>    *
>> - * Copyright (c) 2018 Amlogic, inc.
>> + * Copyright (c) 2018-2021 Amlogic, inc.
>>    * Author: Liang Yang <liang.yang@amlogic.com>
>>    */
>>   
>> @@ -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>
>> @@ -55,6 +56,7 @@
>>   #define NFC_REG_VER		0x38
>>   
>>   #define NFC_RB_IRQ_EN		BIT(21)
>> +#define NFC_CMD_FIFO_RESET	BIT(31)
>>   
>>   #define CMDRWGEN(cmd_dir, ran, bch, short_mode, page_size, pages)	\
>>   	(								\
>> @@ -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;
> 
> I would have been nice to explain why these clock are no longer
> required, in the change description maybe ?

i got the reply from our vlsi members that rx and tx doesn't make sense 
to meson NFC timing. so previous commit about this should be wrong.
> 
>> +	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 *reg_clk;
>>   	struct completion completion;
>>   	struct list_head chips;
>>   	const struct meson_nfc_data *data;
>> @@ -406,12 +411,14 @@ 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);
>> -
>> +	meson_nfc_drain_cmd(nfc);
> 
> is this clock related ?
ok, i will split it in another patch.
> 
>>   	ret = wait_for_completion_timeout(&nfc->completion,
>>   					  msecs_to_jiffies(timeout_ms));
>>   	if (ret == 0)
>>   		ret = -1;
>>   
>> +	/* reset command fifo to avoid lock */
>> +	writel(NFC_CMD_FIFO_RESET, nfc->reg_base + NFC_REG_CMD);
> 
> Again, not seem to be clock related - does not belong in this patch
ok, i will split it in another patch.
> 
>>   	return ret;
>>   }
>>   
>> @@ -988,8 +995,9 @@ static const struct mtd_ooblayout_ops meson_ooblayout_ops = {
>>   static int meson_nfc_clk_init(struct meson_nfc *nfc)
>>   {
>>   	int ret;
>> +	struct clk_init_data init = {0};
>> +	const char *fix_div2_pll_name[1];
>>   
>> -	/* request core clock */
> 
> Why is the comment bothering you ?
> 
>>   	nfc->core_clk = devm_clk_get(nfc->dev, "core");
>>   	if (IS_ERR(nfc->core_clk)) {
>>   		dev_err(nfc->dev, "failed to get core clock\n");
>> @@ -1002,21 +1010,25 @@ 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;
>> +	fix_div2_pll_name[0] = __clk_get_name(nfc->device_clk);
> 
> You should be using "fw_name" so CCF looks a DT directly, instead of this
ok
> 
>> +	init.parent_names = fix_div2_pll_name;
>> +	init.num_parents = 1;
>> +	nfc->nand_divider.reg = nfc->reg_clk;
>> +	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->reg_clk), nfc->reg_clk);
>>   
>>   	ret = clk_prepare_enable(nfc->core_clk);
>>   	if (ret) {
>> @@ -1030,29 +1042,21 @@ 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;
>> -	}
>> -
>> -	ret = clk_prepare_enable(nfc->phase_rx);
>> -	if (ret) {
>> -		dev_err(nfc->dev, "failed to enable RX clock\n");
>> -		goto err_phase_rx;
>> +		dev_err(nfc->dev, "pre enable NFC divider fail\n");
>> +		goto err_nand_clk;
>>   	}
>>   
>>   	ret = clk_set_rate(nfc->device_clk, 24000000);
>>   	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 +1065,7 @@ 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);
>>   }
>> @@ -1375,6 +1378,7 @@ static int meson_nfc_probe(struct platform_device *pdev)
>>   	struct device *dev = &pdev->dev;
>>   	struct meson_nfc *nfc;
>>   	struct resource *res;
>> +	u32 ext_clk_reg;
>>   	int ret, irq;
>>   
>>   	nfc = devm_kzalloc(dev, sizeof(*nfc), GFP_KERNEL);
>> @@ -1396,9 +1400,15 @@ static int meson_nfc_probe(struct platform_device *pdev)
>>   	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");
>> +	ret = of_property_read_u32(pdev->dev.of_node,
>> +				   "sd_emmc_c_clkc",
>> +				   &ext_clk_reg);
>> +	if (ret) {
>> +		dev_err(dev, "failed to get NAND external clock register\n");
>> +		return ret;
>> +	}
>> +
>> +	nfc->reg_clk = devm_ioremap(&pdev->dev, ext_clk_reg, sizeof(int));
> 
> That's how you should get a register region.
> If you want an example of a device claiming several region on amlogic,
> have a look at the pinctrl driver.
ok
> 
>>   	if (IS_ERR(nfc->reg_clk)) {
>>   		dev_err(dev, "Failed to lookup clock base\n");
>>   		return PTR_ERR(nfc->reg_clk);
> 
> .