Re: [RFC PATCH 3/9] of: mtd: add NAND timings retrieval support

boris brezillon <b.brezillon@xxxxxxxxxxx> · Wed, 08 Jan 2014 17:36:34 +0100

On 08/01/2014 17:30, Rob Herring wrote:
On Wed, Jan 8, 2014 at 8:21 AM, Boris BREZILLON <b.brezillon@xxxxxxxxxxx> wrote:
Add a function to retrieve NAND timings from a given DT node.

Signed-off-by: Boris BREZILLON <b.brezillon@xxxxxxxxxxx>
---
  drivers/of/of_mtd.c    |   47 +++++++++++++++++++++++++++++++++++++++++++++++
  include/linux/of_mtd.h |    9 +++++++++
  2 files changed, 56 insertions(+)

diff --git a/drivers/of/of_mtd.c b/drivers/of/of_mtd.c
index a27ec94..52e07fd 100644
--- a/drivers/of/of_mtd.c
+++ b/drivers/of/of_mtd.c
@@ -83,3 +83,50 @@ bool of_get_nand_on_flash_bbt(struct device_node *np)
         return of_property_read_bool(np, "nand-on-flash-bbt");
  }
  EXPORT_SYMBOL_GPL(of_get_nand_on_flash_bbt);
+
+/**
+ * of_get_nand_timings - Get nand timings for the given device_node
+ * @np:        Pointer to the given device_node
+ *
+ * return 0 on success errno other wise
+ */
+int of_get_nand_timings(struct device_node *np, struct nand_timings *timings)
+{
+       memset(timings, 0, sizeof(*timings));
+
+       of_property_read_u32(np, "tCLS-min", &timings->tCLS_min);
+       of_property_read_u32(np, "tCLH-min", &timings->tCLH_min);
+       of_property_read_u32(np, "tCS-min", &timings->tCS_min);
+       of_property_read_u32(np, "tCH-min", &timings->tCH_min);
+       of_property_read_u32(np, "tWP-min", &timings->tWP_min);
+       of_property_read_u32(np, "tALS-min", &timings->tALS_min);
+       of_property_read_u32(np, "tALH-min", &timings->tALH_min);
+       of_property_read_u32(np, "tDS-min", &timings->tDS_min);
+       of_property_read_u32(np, "tDH-min", &timings->tDH_min);
+       of_property_read_u32(np, "tWC-min", &timings->tWC_min);
+       of_property_read_u32(np, "tWH-min", &timings->tWH_min);
+       of_property_read_u32(np, "tR-max", &timings->tR_max);
+       of_property_read_u32(np, "tAR-min", &timings->tAR_min);
+       of_property_read_u32(np, "tCLR-min", &timings->tCLR_min);
+       of_property_read_u32(np, "tRR-min", &timings->tRR_min);
+       of_property_read_u32(np, "tRP-min", &timings->tRP_min);
+       of_property_read_u32(np, "tWB-max", &timings->tWB_max);
+       of_property_read_u32(np, "tRC-min", &timings->tRC_min);
+       of_property_read_u32(np, "tREA-max", &timings->tREA_max);
+       of_property_read_u32(np, "tRHZ-max", &timings->tRHZ_max);
+       of_property_read_u32(np, "tCHZ-max", &timings->tCHZ_max);
+       of_property_read_u32(np, "tRHOH-min", &timings->tRHOH_min);
+       of_property_read_u32(np, "tRLOH-min", &timings->tRLOH_min);
+       of_property_read_u32(np, "tCOH-min", &timings->tCOH_min);
+       of_property_read_u32(np, "tREH-min", &timings->tREH_min);
+       of_property_read_u32(np, "tWHR-min", &timings->tWHR_min);
+       of_property_read_u32(np, "tRHW-min", &timings->tRHW_min);
+       of_property_read_u32(np, "tIR-min", &timings->tIR_min);
+       of_property_read_u32(np, "tCR-min", &timings->tCR_min);
+       of_property_read_u32(np, "tADL-min", &timings->tADL_min);
+       of_property_read_u32(np, "tRST-max", &timings->tRST_max);
+       of_property_read_u32(np, "tWW-min", &timings->tWW_min);
These all need to be documented.
They're document in PATCH 4/9 (but the description might be a bit
light).
These apply to which compatible
strings?
Actually this could apply to any nand chips.
The NAND Flash Controller driver is then responsible for converting
these values to use it.
They should also be suffixed with the unit the property is in
(i.e. -ms, -us, -ns).

Sure, I'll add the unit (which is -ns BTW).

Thanks.

Best Regards,

Boris

Rob

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