Re: [PATCHv5 2/3] ARM: socfpga: dts: Add support for SD/MMC

Re: [PATCHv5 2/3] ARM: socfpga: dts: Add support for SD/MMC

[Stephen Warren]

On 08/23/2013 05:01 PM, Dinh Nguyen wrote:
> On Fri, 2013-08-23 at 16:29 -0600, Stephen Warren wrote:
>> On 08/23/2013 09:44 AM, dinguyen@altera.com wrote:
>>> From: Dinh Nguyen <dinguyen@altera.com>
>>>
>>> Add bindings for SD/MMC for SOCFPGA.
>>
>>> diff --git a/Documentation/devicetree/bindings/mmc/socfpga-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/socfpga-dw-mshc.txt
>>
>>> +* altr,sysmgr: Should be the phandle to the system_mgr node. As this is where
>>> +		this where the register that controls the CIU clock phases
>>> +		reside.
>>> +
>>> +* altr,ciu-clk-offset: The order of the cells should be:
>>> +	- First Cell: Offset of the register in the system_mgr node that controls
>>> +		the smpsel bits.
>>> +	- Second Cell: Shift value of the drvsel bits.
>>> +	- Third Cell: Shift value of the smpsel bits.
>>
>> This almost solves the issues I was thinking of. A few more thoughts though:
>>
>> * What if the sysmgr node has multiple reg entries. Is the offset cell
>> in altr,ciu-clk-offset an offset from the first reg entry, or across all
>> reg entries? It might be better to specify this as a reg index plus
>> offset, or allow the sysmgr node to define the format (#sysmgr-cells
>> perhaps).
>>
>> * What if the drvsel and smpsel bits are in different registers, even
>> different sysmgr blocks? Wouldn't it be better to have 2 separate
>> properties, each one defining the location of one bit-field?
>>
>> * bikeshed: altr,ciu-clk-offset isn't a great name; the value is more
>> than just an offset.
>>
>> Putting those together, I might expect the following properties:
>>
>> sysmgr: sysmgr {
>>     /* binding for sysmgr node must specify what those 3 cells are */
>>     #sysmgr-cells = <3>;
>> }
>>
>> dwmmc {
>>     altr,drvsel-reg-field = <
>>         &sysmgr /* sysmgr phandle */
>>         0 /* reg index */
>>         0 /* reg offset */
>>         0 /* field bit position */
>>         3 /* field bit size */>;
>>     altr,smpsel-reg-field = <
>>         &sysmgr /* sysmgr phandle */
>>         0 /* reg index */
>>         0 /* reg offset */
>>         3 /* field bit position */
>>         3 /* field bit size */>;
>> };
>>
>> That would allow the whole sysmgr concept to be completely generic.
>>
>> But, this is a bit like representing raw register I/O in DT, which has
>> been frowned upon in the past.
>>
>> Finally, what if the values for drvsel, smpsel are different in
>> different sysmgr implementations? Do you need a property that defines
>> that values?
>>
>> Another option might be to define a semantic API between the two, such
>> that you only need a sysmgr=<&sysmgr> property, yet the driver for the
>> sysmgr node exposes a function sysmgr_set_dwmmc_drvsel_smpsel(struct
>> device_node *sysmgr_node, uint drvsel, uint smpsel); Now, the sysmgr
>> driver would have to implement that on any SoC that supported a dwmmc.
> 
> I was trying to avoid adding a driver for the sysmgr, as it really does
> not represent any type of device. It is a merely a register region with
> miscellaneous registers that controls other IPs in the SOC.
> 
> I'm thinking perhaps I can set this register in the arch specific file,
> then the SD/MMC driver would not need to bother with it at all?

The problem with hard-coding this in the MMC driver is that it makes the
MMC driver depend on information outside the MMC HW block. If you do
that, you may as well just write the "syscon" registers directly in the
MMC driver.

Re: [PATCHv5 2/3] ARM: socfpga: dts: Add support for SD/MMC

[Steffen Trumtrar]

Hi!

On Fri, Aug 23, 2013 at 10:44:45AM -0500, dinguyen@altera.com wrote:
> From: Dinh Nguyen <dinguyen@altera.com>
> 
> Add bindings for SD/MMC for SOCFPGA.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
> Cc: Jaehoon Chung <jh80.chung@samsung.com>
> Cc: Seungwon Jeon <tgih.jun@samsung.com>
> Cc: Rob Herring <rob.herring@calxeda.com>
> Cc: Pawel Moll <pawel.moll@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Stephen Warren <swarren@wwwdotorg.org>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: devicetree@vger.kernel.org
> Cc: linux-mmc@vger.kernel.org
> CC: linux-arm-kernel@lists.infradead.org
> 
> v5:
> - Add "altr,ciu-clk-offset" that represents the necessary offset
>   and shift values in the sysmgr phandle. This is used to set
>   the correct CIU clock values.
> 
> v4:
> - Add a complete binding example in documentations
> - Add a phandle entry for "altr,sysmgr" which links the system
>   manager to the SD/MMC IP block that controls the SDR timings.
> - Split up patches
>         1/3 - Add syscon binding to sys-mgr node
>         2/3 - DTS bindings and documentation for SD/MMC on SOCFPGA
>         3/3 - Driver changes to use the bindings
> 
> v3:
> - Explicitly reference synopsis-dw-mshc.txt for base bindings
> - Remove "dw-mshc-ciu-div" as driver can get clock information dts "ciu" entry
> - Fixed indentation issue
> 
> v2:
> - Remove bus-width and extra line in documentation
> - Merge bindings example into a single node in documentation
> ---

You should put your changelogs here and not above the ---
AFAIK nobody cares for the development history of a patch once it is applied.

>  .../devicetree/bindings/mmc/socfpga-dw-mshc.txt    |   63 ++++++++++++++++++++
>  arch/arm/boot/dts/socfpga.dtsi                     |   11 ++++
>  arch/arm/boot/dts/socfpga_cyclone5.dts             |   14 +++++
>  arch/arm/boot/dts/socfpga_vt.dts                   |   14 +++++
>  4 files changed, 102 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mmc/socfpga-dw-mshc.txt
> 

Regards,
Steffen

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

RE: [PATCHv5 3/3] mmc: dw_mmc: Use phandle to get SDR timing values from sys-mgr

[Seungwon Jeon]

On Saturday, August 24, 2013, Dinh Nguyen wrote:
> From: Dinh Nguyen <dinguyen@altera.com>
> 
> Update the driver to get the system manager node from a phandle. Also, the
> driver can get the correct clock value from the common clock API, thus the
> "altr,dw-mshc-ciu-div" binding is not needed at all.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
> Cc: Jaehoon Chung <jh80.chung@samsung.com>
> Cc: Seungwon Jeon <tgih.jun@samsung.com>
> Cc: Rob Herring <rob.herring@calxeda.com>
> Cc: Pawel Moll <pawel.moll@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Stephen Warren <swarren@wwwdotorg.org>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Chris Ball <cjb@laptop.org>
> Cc: devicetree@vger.kernel.org
> Cc: linux-mmc@vger.kernel.org
> CC: linux-arm-kernel@lists.infradead.org
> 
> v2:
> - Use "altr,ciu-clk-offset" to get the correct CIU clock values to be
>   set in the system manager.
> ---
>  drivers/mmc/host/dw_mmc-socfpga.c |   33 +++++++++++++++------------------
>  1 file changed, 15 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc-socfpga.c b/drivers/mmc/host/dw_mmc-socfpga.c
> index 14b5961..cfd67e1 100644
> --- a/drivers/mmc/host/dw_mmc-socfpga.c
> +++ b/drivers/mmc/host/dw_mmc-socfpga.c
> @@ -24,21 +24,20 @@
>  #include "dw_mmc.h"
>  #include "dw_mmc-pltfm.h"
> 
> -#define SYSMGR_SDMMCGRP_CTRL_OFFSET		0x108
> -#define DRV_CLK_PHASE_SHIFT_SEL_MASK	0x7
> -#define SYSMGR_SDMMC_CTRL_SET(smplsel, drvsel)          \
> -	((((smplsel) & 0x7) << 3) | (((drvsel) & 0x7) << 0))
> +#define DRV_CLK_PHASE_SHIFT_SEL_MASK   0x7
> 
>  /* SOCFPGA implementation specific driver private data */
>  struct dw_mci_socfpga_priv_data {
> -	u8	ciu_div; /* card interface unit divisor */
>  	u32	hs_timing; /* bitmask for CIU clock phase shift */
>  	struct regmap   *sysreg; /* regmap for system manager register */
> +	/* Offset for the ciu clock setting register inside the system manager.*/
> +	u32     ciu_clk_offset;
>  };
> 
>  static int dw_mci_socfpga_priv_init(struct dw_mci *host)
>  {
>  	struct dw_mci_socfpga_priv_data *priv;
> +	struct device_node *np = host->dev->of_node;
> 
>  	priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
>  	if (!priv) {
> @@ -46,9 +45,9 @@ static int dw_mci_socfpga_priv_init(struct dw_mci *host)
>  		return -ENOMEM;
>  	}
> 
> -	priv->sysreg = syscon_regmap_lookup_by_compatible("altr,sys-mgr");
> +	priv->sysreg = syscon_regmap_lookup_by_phandle(np, "altr,sysmgr");
>  	if (IS_ERR(priv->sysreg)) {
> -		dev_err(host->dev, "regmap for altr,sys-mgr lookup failed.\n");
> +		dev_err(host->dev, "No sysmgr phandle specified!\n");
>  		return PTR_ERR(priv->sysreg);
>  	}
>  	host->priv = priv;
> @@ -61,11 +60,8 @@ static int dw_mci_socfpga_setup_clock(struct dw_mci *host)
>  	struct dw_mci_socfpga_priv_data *priv = host->priv;
> 
>  	clk_disable_unprepare(host->ciu_clk);
> -	regmap_write(priv->sysreg, SYSMGR_SDMMCGRP_CTRL_OFFSET,
> -		priv->hs_timing);
> +	regmap_write(priv->sysreg, priv->ciu_clk_offset, priv->hs_timing);
>  	clk_prepare_enable(host->ciu_clk);
> -
> -	host->bus_hz /= (priv->ciu_div + 1);
>  	return 0;
>  }
> 
> @@ -82,20 +78,21 @@ static int dw_mci_socfpga_parse_dt(struct dw_mci *host)
>  	struct dw_mci_socfpga_priv_data *priv = host->priv;
>  	struct device_node *np = host->dev->of_node;
>  	u32 timing[2];
> -	u32 div = 0;
> +	u32 offset[3];
>  	int ret;
> 
> -	ret = of_property_read_u32(np, "altr,dw-mshc-ciu-div", &div);
> -	if (ret)
> -		dev_info(host->dev, "No dw-mshc-ciu-div specified, assuming 1");
> -	priv->ciu_div = div;
> -
>  	ret = of_property_read_u32_array(np,
>  			"altr,dw-mshc-sdr-timing", timing, 2);
>  	if (ret)
>  		return ret;
> 
> -	priv->hs_timing = SYSMGR_SDMMC_CTRL_SET(timing[0], timing[1]);
> +	ret = of_property_read_u32_array(np, "altr,ciu-clk-offset", offset, 3);
> +	if (ret)
> +		return ret;
> +
> +	priv->ciu_clk_offset = offset[0];
> +	priv->hs_timing =
> +		((((timing[0]) & 0x7) << offset[2]) | (((timing[1]) & 0x7) << offset[1]));
offset should be gotten from DT?
These are variable?

Thanks,
Seungwon Jeon

>  	return 0;
>  }
> 
> --
> 1.7.9.5
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html