RE: [PATCH] mtd: atmel_nand: move the hsmc_clk from nfc node to nand node

[Yang, Wenyou]

> -----Original Message-----
> From: Ferre, Nicolas
> Sent: 2016年2月22日 20:57
> To: Yang, Wenyou <Wenyou.Yang@xxxxxxxxx>; Brian Norris
> <computersforpeace@xxxxxxxxx>; David Woodhouse <dwmw2@xxxxxxxxxxxxx>;
> Josh Wu <rainyfeeling@xxxxxxxxxxx>
> Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Wu, Josh <Josh.wu@xxxxxxxxx>
> Subject: Re: [PATCH] mtd: atmel_nand: move the hsmc_clk from nfc node to nand
> node
> 
> Le 17/02/2016 06:40, Wenyou Yang a écrit :
> > From: Josh Wu <josh.wu@xxxxxxxxx>
> >
> > For sama5d3, sama5d4 chip, the pmecc becomes a part of HSMC, they need
> > the HSMC clock to be enabled to work.
> > The NFC is a sub feature for current nand driver, it can be disabled.
> > But if HSMC clock is controlled by NFC, so disable NFC will also
> > disable the HSMC clock. then, it will make the PMECC fail to work.
> >
> > So the solution is to move the HSMC clock out of NFC to nand node.
> > When nand driver probed, it will check whether the chip has HSMC, if
> > yes then it will require a HSMC clock.
> >
> > Signed-off-by: Josh Wu <josh.wu@xxxxxxxxx>
> > Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
> > ---
> >
> >  .../devicetree/bindings/mtd/atmel-nand.txt         |    4 +-
> >  drivers/mtd/nand/atmel_nand.c                      |   43 +++++++++-----------
> >  2 files changed, 22 insertions(+), 25 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> > b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> > index d53aba9..29bee7c 100644
> > --- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> > +++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> > @@ -15,6 +15,7 @@ Required properties:
> >  - atmel,nand-cmd-offset : offset for the command latch.
> >  - #address-cells, #size-cells : Must be present if the device has sub-nodes
> >    representing partitions.
> > +- clocks: phandle to the peripheral clock
> >
> >  - gpios : specifies the gpio pins to control the NAND device. detect is an
> >    optional gpio and may be set to 0 if not present.
> > @@ -43,7 +44,6 @@ Required properties:
> >  - reg : should specify the address and size used for NFC command registers,
> >          NFC registers and NFC SRAM. NFC SRAM address and size can be
> absent
> >          if don't want to use it.
> > -- clocks: phandle to the peripheral clock  Optional properties:
> >  - atmel,write-by-sram: boolean to enable NFC write by SRAM.
> >
> > @@ -100,13 +100,13 @@ nand0: nand@40000000 {
> >  	compatible = "atmel,at91rm9200-nand";
> >  	#address-cells = <1>;
> >  	#size-cells = <1>;
> > +	clocks = <&hsmc_clk>
> >  	ranges;
> >          ...
> >          nfc@70000000 {
> >  		compatible = "atmel,sama5d3-nfc";
> >  		#address-cells = <1>;
> >  		#size-cells = <1>;
> > -		clocks = <&hsmc_clk>
> >  		reg = <
> >  			0x70000000 0x10000000	/* NFC Command
> Registers */
> >  			0xffffc000 0x00000070	/* NFC HSMC regs */
> > diff --git a/drivers/mtd/nand/atmel_nand.c
> > b/drivers/mtd/nand/atmel_nand.c index 20cbaab..a1f4ad2 100644
> > --- a/drivers/mtd/nand/atmel_nand.c
> > +++ b/drivers/mtd/nand/atmel_nand.c
> > @@ -66,6 +66,7 @@ module_param(on_flash_bbt, int, 0);  struct
> > atmel_nand_caps {
> >  	bool pmecc_correct_erase_page;
> >  	uint8_t pmecc_max_correction;
> > +	bool has_hsmc_clk;
> >  };
> >
> >  struct atmel_nand_nfc_caps {
> > @@ -106,8 +107,6 @@ struct atmel_nfc {
> >  	bool			use_nfc_sram;
> >  	bool			write_by_sram;
> >
> > -	struct clk		*clk;
> > -
> >  	bool			is_initialized;
> >  	struct completion	comp_ready;
> >  	struct completion	comp_cmd_done;
> > @@ -132,6 +131,7 @@ struct atmel_nand_host {
> >  	struct dma_chan		*dma_chan;
> >
> >  	struct atmel_nfc	*nfc;
> > +	struct clk		*clk;
> >
> >  	const struct atmel_nand_caps	*caps;
> >  	bool			has_pmecc;
> > @@ -2157,6 +2157,19 @@ static int atmel_nand_probe(struct platform_device
> *pdev)
> >  	nand_chip->IO_ADDR_R = host->io_base;
> >  	nand_chip->IO_ADDR_W = host->io_base;
> >
> > +	if (host->caps->has_hsmc_clk) {
> > +		host->clk = devm_clk_get(&pdev->dev, NULL);
> > +		if (IS_ERR(host->clk)) {
> > +			dev_err(&pdev->dev, "HSMC clock is missing, update
> your Device Tree");
> > +			res = PTR_ERR(host->clk);
> > +			goto err_nand_ioremap;
> > +		}
> > +
> > +		res = clk_prepare_enable(host->clk);
> > +		if (res)
> > +			goto err_nand_ioremap;
> > +	}
> > +
> >  	if (nand_nfc.is_initialized) {
> >  		/* NFC driver is probed and initialized */
> >  		host->nfc = &nand_nfc;
> > @@ -2321,6 +2334,9 @@ static int atmel_nand_remove(struct platform_device
> *pdev)
> >  	if (host->dma_chan)
> >  		dma_release_channel(host->dma_chan);
> >
> > +	if (!IS_ERR(host->clk))
> > +		clk_disable_unprepare(host->clk);
> > +
> >  	platform_driver_unregister(&atmel_nand_nfc_driver);
> >
> >  	return 0;
> > @@ -2334,11 +2350,13 @@ static int atmel_nand_remove(struct
> > platform_device *pdev)  static const struct atmel_nand_caps at91rm9200_caps
> = {
> >  	.pmecc_correct_erase_page = false,
> >  	.pmecc_max_correction = 24,
> > +	.has_hsmc_clk = false,
> >  };
> >
> >  static const struct atmel_nand_caps sama5d4_caps = {
> >  	.pmecc_correct_erase_page = true,
> >  	.pmecc_max_correction = 24,
> > +	.has_hsmc_clk = true,
> 
> As this capability is not shared with SAMA5D3, I didn't see how you could make
> the hsmc clock probed on SAMA5D3: remember, its controller compatibility string
> is "atmel,at91rm9200-nand" with the description just above.

Sorry.
It is my carelessness, missing the " atmel,sama5d3-nand" compatible string part. I will add it.

> 
> Bye,
> 
> 
> >  };
> >
> >  /*
> > @@ -2363,7 +2381,6 @@ static int atmel_nand_nfc_probe(struct
> > platform_device *pdev)  {
> >  	struct atmel_nfc *nfc = &nand_nfc;
> >  	struct resource *nfc_cmd_regs, *nfc_hsmc_regs, *nfc_sram;
> > -	int ret;
> >
> >  	nfc_cmd_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >  	nfc->base_cmd_regs = devm_ioremap_resource(&pdev->dev,
> > nfc_cmd_regs); @@ -2401,31 +2418,12 @@ static int
> atmel_nand_nfc_probe(struct platform_device *pdev)
> >  	nfc_writel(nfc->hsmc_regs, IDR, 0xffffffff);
> >  	nfc_readl(nfc->hsmc_regs, SR);	/* clear the NFC_SR */
> >
> > -	nfc->clk = devm_clk_get(&pdev->dev, NULL);
> > -	if (!IS_ERR(nfc->clk)) {
> > -		ret = clk_prepare_enable(nfc->clk);
> > -		if (ret)
> > -			return ret;
> > -	} else {
> > -		dev_warn(&pdev->dev, "NFC clock missing, update your Device
> Tree");
> > -	}
> > -
> >  	nfc->is_initialized = true;
> >  	dev_info(&pdev->dev, "NFC is probed.\n");
> >
> >  	return 0;
> >  }
> >
> > -static int atmel_nand_nfc_remove(struct platform_device *pdev) -{
> > -	struct atmel_nfc *nfc = &nand_nfc;
> > -
> > -	if (!IS_ERR(nfc->clk))
> > -		clk_disable_unprepare(nfc->clk);
> > -
> > -	return 0;
> > -}
> > -
> >  static const struct atmel_nand_nfc_caps sama5d3_nfc_caps = {
> >  	.rb_mask = NFC_SR_RB_EDGE0,
> >  };
> > @@ -2447,7 +2445,6 @@ static struct platform_driver atmel_nand_nfc_driver =
> {
> >  		.of_match_table = of_match_ptr(atmel_nand_nfc_match),
> >  	},
> >  	.probe = atmel_nand_nfc_probe,
> > -	.remove = atmel_nand_nfc_remove,
> >  };
> >
> >  static struct platform_driver atmel_nand_driver = {
> >
> 
> 
> --
> Nicolas Ferre


Best Regards,
Wenyou Yang