[PATCH v4 4/4] memory: emif: add device tree support to emif driver

[Shilimkar, Santosh]

Greg,

On Wed, Jul 18, 2012 at 12:14 PM, Shilimkar, Santosh
<santosh.shilimkar at ti.com> wrote:
> On Tue, Jul 17, 2012 at 11:28 PM, Greg KH <gregkh at linuxfoundation.org> wrote:
>> On Tue, Jul 17, 2012 at 10:37:45PM +0530, Shilimkar, Santosh wrote:
>>> On Tue, Jul 17, 2012 at 10:06 PM, Greg KH <gregkh at linuxfoundation.org> wrote:
>>> > On Mon, Jul 09, 2012 at 07:02:36PM +0530, Shilimkar, Santosh wrote:
>>> >> Greg,
>>> >>
>
> [..]
>
>>> >From 74688a87fd490909e9122bf757c0096480e9fc11 Mon Sep 17 00:00:00 2001
>>> From: Aneesh V <aneesh at ti.com>
>>> Date: Mon, 30 Jan 2012 20:06:30 +0530
>>> Subject: [PATCH 4/4] memory: emif: add device tree support to emif driver
>>>
>>> Device tree support for the EMIF driver. LPDDR2 generic timings
>>> extraction from device is managed using couple of helper
>>> functions which can be used by other memory controller
>>> drivers.
>>>
>>> Reviewed-by: Benoit Cousson <b-cousson at ti.com>
>>> Reviewed-by: Grant Likely <grant.likely at secretlab.ca>
>>> Tested-by: Lokesh Vutla <lokeshvutla at ti.com>
>>> Signed-off-by: Aneesh V <aneesh at ti.com>
>>> Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
>>> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
>>> ---
>>>  drivers/memory/Makefile    |    1 +
>>>  drivers/memory/emif.c      |  182 +++++++++++++++++++++++++++++++++++++++++++-
>>>  drivers/memory/of_memory.c |  153 +++++++++++++++++++++++++++++++++++++
>>>  drivers/memory/of_memory.h |   36 +++++++++
>>>  4 files changed, 371 insertions(+), 1 deletion(-)
>>>  create mode 100644 drivers/memory/of_memory.c
>>>  create mode 100644 drivers/memory/of_memory.h
>>>
>>> diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
>>> index 42b3ce9..cd8486b 100644
>>> --- a/drivers/memory/Makefile
>>> +++ b/drivers/memory/Makefile
>>> @@ -2,6 +2,7 @@
>>>  # Makefile for memory devices
>>>  #
>>>
>>> +obj-$(CONFIG_OF)             += of_memory.o
>>>  obj-$(CONFIG_TI_EMIF)                += emif.o
>>>  obj-$(CONFIG_TEGRA20_MC)     += tegra20-mc.o
>>>  obj-$(CONFIG_TEGRA30_MC)     += tegra30-mc.o
>>> diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
>>> index 33a4396..06b4eb7 100644
>>> --- a/drivers/memory/emif.c
>>> +++ b/drivers/memory/emif.c
>>> @@ -18,6 +18,7 @@
>>>  #include <linux/platform_device.h>
>>>  #include <linux/interrupt.h>
>>>  #include <linux/slab.h>
>>> +#include <linux/of.h>
>>>  #include <linux/debugfs.h>
>>>  #include <linux/seq_file.h>
>>>  #include <linux/module.h>
>>> @@ -25,6 +26,7 @@
>>>  #include <linux/spinlock.h>
>>>  #include <memory/jedec_ddr.h>
>>>  #include "emif.h"
>>> +#include "of_memory.h"
>>>
>>>  /**
>>>   * struct emif_data - Per device static data for driver's use
>>> @@ -49,6 +51,7 @@
>>>   *                           frequency in effect at the moment)
>>>   * @plat_data:                       Pointer to saved platform data.
>>>   * @debugfs_root:            dentry to the root folder for EMIF in debugfs
>>> + * @np_ddr:                  Pointer to ddr device tree node
>>>   */
>>>  struct emif_data {
>>>       u8                              duplicate;
>>> @@ -63,6 +66,7 @@ struct emif_data {
>>>       struct emif_regs                *curr_regs;
>>>       struct emif_platform_data       *plat_data;
>>>       struct dentry                   *debugfs_root;
>>> +     struct device_node              *np_ddr;
>>>  };
>>>
>>>  static struct emif_data *emif1;
>>> @@ -1148,6 +1152,168 @@ static int is_custom_config_valid(struct
>>> emif_custom_configs *cust_cfgs,
>>>       return valid;
>>>  }
>>>
>>> +#if defined(CONFIG_OF)
>>> +static void __init_or_module of_get_custom_configs(struct device_node *np_emif,
>>> +             struct emif_data *emif)
>>
>> Why can't all of this code be in the of_memory.c file?
>>
> Primarily because the parameters are very much specific to EMIF
> memory controller and won't be of much use for other memory controllers.
>
> Currently the information extracted from DT with these function is like:
> - EMIF controller IP version : EMIF_4D or EMIF_4D5
> - Which analog phy is integrated : EMIF_ATTILAPHY or EMIF_ATTILAPHY
> - IP hardware interface: EMIF Low latency port or sys port interface.
> - EMIF connections - Whether EMIF1 only, EMIF2 only or EMIF1 & EMIF2
> - Memory connections to EMIF - Same type and size memories or asymmetric
> - Chip select usage per controller: Whether CS0, CS1, CS0 & CS1
> - ZQ calibration - Per chip select or enable EMIF dual calibration feature.
> - Enable/disable EMIF Low power mode and temperature alerts.
> - EMIF low power mode configuration:
>       - Clock stop, self refresh, Deep power down.
>       - Low power time out values for performance and power mode.
>       - DDR frequency threshold to switch between power and
> performance settings.
> - EMIF temperature polling cycle configuration.
>
> As you can see these are very specific to the EMIF memory controller and hence
> I didn't move them to of_memory.c
>
Do you have any more comment on this patch? If not, I can go ahead and
post the refreshed version of the patch.

Regards
Santosh