[PATCH v7 0/5] OMAP GPMC DT bindings

[PATCH v7 0/5] OMAP GPMC DT bindings

[Daniel Mack]

This is a series of patches to support GPMC peripherals on OMAP boards.

Grant, Rob, could you have a look and give your Acked-by if
appropriate?


Many thanks again,
Daniel


Tested on Linus' master +
omap-next (branch omap-for-v3.8/cleanup-headers-gpmc)

Generated from linux-next as of today, resolving one trivial include
file rebase conflict.

The only supported peripheral for now is NAND, but other types would be
easy to add.

Version 2 addresses details pointed out by Jon Hunter, Afzal Mohammed
and Rob Herring:

 - add "reg" and "ti,hwmod" properties to Documentation
 - use generic of_mtd functions and the property names defined by them,
   namely "nand-bus-width" and "nand-ecc-mode"
 - reduce the default register space size in the Documentation to 8K,
   as found in the hwmod code
 - switch to a DT layout based on ranges and address translation.
   Although this property is not currently looked at as long as the
   handling code still uses the runtime calculation methods, we now
   have these values in the bindings, eventually allowing us to
   switch the implementation with less pain.

Version 3 includes fixes pointed out by Jon Hunter:

 - better documentation of the 'ranges' property to describe the
   fact that it's representing the CS lines
 - GPMC_CS_CONFIGx -> GPMC_CONFIGx in comments
 - drop interrupt-parent from example bindings
 - add of_node_put() at the end of the child iteration

Version 4 fixes compilation for !CONFIG_MTD_NAND and includes more
details from Jon Hunter and Avinash, Philip:

 - Add "num-cs" and "num-waitpins" properties, which will eventually
   be used to get rid of GPMC_CS_NUM
 - Better description of generic nand DT properties
 - Dropped patch 3/4 as an equivalent fix was already merged
 - Added ti,nand-ecc-use-elm property

Version 5 with regards to Avinash, Philip and Peter Korsgaard:

 - Re-add accidentially forgotten
   Documentation/devicetree/bindings/bus/ti-gpmc.txt
 - Rename "software" ecc mode to "sw"
 - Initialize gpmc_nand_data->is_elm_used to 'true' rather than 1
 - Drop ti,nand-ecc-use-elm binding in favor of a new ecc mode
   named "bch8-am335xrbl-compatible"
 - Add two more patches for section mismatch fixups

Version 6:

 - Dropped "bch8-am335xrbl-compatible" mode again. As discussed with
   Avinash, the ELM issue will be solved subsequently in s separate
   series.
 - re-added a patch to bail out of automatic GPMC instanciation in
   case of DT boot.
 - re-added the "of_node" addition in mtd_nand_omap2.h in 2/5

Version 7: comments from Jon Hunter, all affecting the documentation:

 - add num-wait pins properties as they are marked 'required'
 - make reg sizes consistent
 - AM335x only has 2 wait-pins

Again, many thanks to everybody, in particular Avinash, for the long
disussion about how to the these details right in the first place.


Daniel

Daniel Mack (5):
  ARM: OMAP: gpmc: don't create devices from initcall on DT
  mtd: omap-nand: pass device_node in platform data
  ARM: OMAP: gpmc-nand: drop __init annotation
  ARM: OMAP: gpmc: enable hwecc for AM33xx SoCs
  ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

 Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  76 +++++++++
 .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
 arch/arm/mach-omap2/gpmc-nand.c                    |  15 +-
 arch/arm/mach-omap2/gpmc.c                         | 178 ++++++++++++++++++++-
 drivers/mtd/nand/omap2.c                           |   4 +-
 include/linux/platform_data/mtd-nand-omap2.h       |   4 +-
 6 files changed, 343 insertions(+), 10 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
 create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt

-- 
1.7.11.7

[PATCH v7 1/5] ARM: OMAP: gpmc: don't create devices from initcall on DT

[Daniel Mack]

On DT driven boards, the gpmc node will match the driver. Hence, there's
no need to do that unconditionally from the initcall.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 arch/arm/mach-omap2/gpmc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 65468f6..d5cbd29 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -1214,6 +1214,13 @@ static int __init omap_gpmc_init(void)
 	struct platform_device *pdev;
 	char *oh_name = "gpmc";
 
+	/*
+	 * if the board boots up with a populated DT, do not
+	 * manually add the device from this initcall
+	 */
+	if (of_have_populated_dt())
+		return -ENODEV;
+
 	oh = omap_hwmod_lookup(oh_name);
 	if (!oh) {
 		pr_err("Could not look up %s\n", oh_name);
-- 
1.7.11.7

[PATCH v7 2/5] mtd: omap-nand: pass device_node in platform data

[Daniel Mack]

Pass an optional device_node pointer in the platform data, which in turn
will be put into a mtd_part_parser_data. This way, code that sets up the
platform devices can pass along the node from DT so that the partitions
can be parsed.

For non-DT boards, this change has no effect.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 drivers/mtd/nand/omap2.c                     | 4 +++-
 include/linux/platform_data/mtd-nand-omap2.h | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 0002d5e..1d333497c 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1332,6 +1332,7 @@ static int omap_nand_probe(struct platform_device *pdev)
 	dma_cap_mask_t mask;
 	unsigned sig;
 	struct resource			*res;
+	struct mtd_part_parser_data	ppdata = {};
 
 	pdata = pdev->dev.platform_data;
 	if (pdata == NULL) {
@@ -1557,7 +1558,8 @@ static int omap_nand_probe(struct platform_device *pdev)
 		goto out_release_mem_region;
 	}
 
-	mtd_device_parse_register(&info->mtd, NULL, NULL, pdata->parts,
+	ppdata.of_node = pdata->of_node;
+	mtd_device_parse_register(&info->mtd, NULL, &ppdata, pdata->parts,
 				  pdata->nr_parts);
 
 	platform_set_drvdata(pdev, &info->mtd);
diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h
index 24d32ca..6bf9ef4 100644
--- a/include/linux/platform_data/mtd-nand-omap2.h
+++ b/include/linux/platform_data/mtd-nand-omap2.h
@@ -60,6 +60,8 @@ struct omap_nand_platform_data {
 	int			devsize;
 	enum omap_ecc           ecc_opt;
 	struct gpmc_nand_regs	reg;
-};
 
+	/* for passing the partitions */
+	struct device_node	*of_node;
+};
 #endif
-- 
1.7.11.7

[PATCH v7 3/5] ARM: OMAP: gpmc-nand: drop __init annotation

[Daniel Mack]

gpmc_nand_init() will be called from another driver's probe() function,
so the easiest way to prevent section mismatches is to drop the
annotation here.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 arch/arm/mach-omap2/gpmc-nand.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-omap2/gpmc-nand.c b/arch/arm/mach-omap2/gpmc-nand.c
index db969a5..3059f5e 100644
--- a/arch/arm/mach-omap2/gpmc-nand.c
+++ b/arch/arm/mach-omap2/gpmc-nand.c
@@ -89,7 +89,7 @@ static int omap2_nand_gpmc_retime(
 	return 0;
 }
 
-static bool __init gpmc_hwecc_bch_capable(enum omap_ecc ecc_opt)
+static bool gpmc_hwecc_bch_capable(enum omap_ecc ecc_opt)
 {
 	/* support only OMAP3 class */
 	if (!cpu_is_omap34xx()) {
@@ -110,8 +110,8 @@ static bool __init gpmc_hwecc_bch_capable(enum omap_ecc ecc_opt)
 	return 1;
 }
 
-int __init gpmc_nand_init(struct omap_nand_platform_data *gpmc_nand_data,
-			  struct gpmc_timings *gpmc_t)
+int gpmc_nand_init(struct omap_nand_platform_data *gpmc_nand_data,
+		   struct gpmc_timings *gpmc_t)
 {
 	int err	= 0;
 	struct device *dev = &gpmc_nand_device.dev;
-- 
1.7.11.7

[PATCH v7 4/5] ARM: OMAP: gpmc: enable hwecc for AM33xx SoCs

[Daniel Mack]

The am33xx is capable of handling bch error correction modes, so
enable that feature in the driver.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 arch/arm/mach-omap2/gpmc-nand.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-omap2/gpmc-nand.c b/arch/arm/mach-omap2/gpmc-nand.c
index 3059f5e..afc1e8c 100644
--- a/arch/arm/mach-omap2/gpmc-nand.c
+++ b/arch/arm/mach-omap2/gpmc-nand.c
@@ -92,17 +92,18 @@ static int omap2_nand_gpmc_retime(
 static bool gpmc_hwecc_bch_capable(enum omap_ecc ecc_opt)
 {
 	/* support only OMAP3 class */
-	if (!cpu_is_omap34xx()) {
+	if (!cpu_is_omap34xx() && !soc_is_am33xx()) {
 		pr_err("BCH ecc is not supported on this CPU\n");
 		return 0;
 	}
 
 	/*
-	 * For now, assume 4-bit mode is only supported on OMAP3630 ES1.x, x>=1.
-	 * Other chips may be added if confirmed to work.
+	 * For now, assume 4-bit mode is only supported on OMAP3630 ES1.x, x>=1
+	 * and AM33xx derivates. Other chips may be added if confirmed to work.
 	 */
 	if ((ecc_opt == OMAP_ECC_BCH4_CODE_HW) &&
-	    (!cpu_is_omap3630() || (GET_OMAP_REVISION() == 0))) {
+	    (!cpu_is_omap3630() || (GET_OMAP_REVISION() == 0)) &&
+	    (!soc_is_am33xx())) {
 		pr_err("BCH 4-bit mode is not supported on this CPU\n");
 		return 0;
 	}
-- 
1.7.11.7

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Daniel Mack]

This patch adds basic DT bindings for OMAP GPMC.

The actual peripherals are instantiated from child nodes within the GPMC
node, and the only type of device that is currently supported is NAND.

Code was added to parse the generic GPMC timing parameters and some
documentation with examples on how to use them.

Successfully tested on an AM33xx board.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  77 ++++++++++
 .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
 arch/arm/mach-omap2/gpmc.c                         | 171 ++++++++++++++++++++-
 3 files changed, 323 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
 create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt

diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
new file mode 100644
index 0000000..7d2a645
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
@@ -0,0 +1,77 @@
+Device tree bindings for OMAP general purpose memory controllers (GPMC)
+
+The actual devices are instantiated from the child nodes of a GPMC node.
+
+Required properties:
+
+ - compatible:		Should be set to "ti,gpmc"
+ - reg:			A resource specifier for the register space
+			(see the example below)
+ - ti,hwmods:		Should be set to "ti,gpmc" until the DT transition is
+			completed.
+ - #address-cells:	Must be set to 2 to allow memory address translation
+ - #size-cells:		Must be set to 1 to allow CS address passing
+ - num-cs:		The maximum number of chip-select lines that controller
+			can support.
+ - num-waitpins:	The maximum number of wait pins that controller can
+			support.
+ - ranges:		Must be set up to reflect the memory layout with four
+			integer values for each chip-select line in use:
+
+			   <cs-number> 0 <physical address of mapping> <size>
+
+			Note that this property is not currently parsed.
+			Calculated values derived from the contents of the
+			per-CS register GPMC_CONFIG7 (as set up by the
+			bootloader) are used. That will change in the future,
+			so be sure to fill the correct values here.
+
+Timing properties for child nodes. All are optional and default to 0.
+
+ - gpmc,sync-clk:	Minimum clock period for synchronous mode, in picoseconds
+
+ Chip-select signal timings corresponding to GPMC_CONFIG2:
+ - gpmc,cs-on:		Assertion time
+ - gpmc,cs-rd-off:	Read deassertion time
+ - gpmc,cs-wr-off:	Write deassertion time
+
+ ADV signal timings corresponding to GPMC_CONFIG3:
+ - gpmc,adv-on:		Assertion time
+ - gpmc,adv-rd-off:	Read deassertion time
+ - gpmc,adv-wr-off:	Write deassertion time
+
+ WE signals timings corresponding to GPMC_CONFIG4:
+ - gpmc,we-on:		Assertion time
+ - gpmc,we-off:		Deassertion time
+
+ OE signals timings corresponding to GPMC_CONFIG4:
+ - gpmc,oe-on:		Assertion time
+ - gpmc,oe-off:		Deassertion time
+
+ Access time and cycle time timings corresponding to GPMC_CONFIG5:
+ - gpmc,page-burst-access: Multiple access word delay
+ - gpmc,access:		Start-cycle to first data valid delay
+ - gpmc,rd-cycle:	Total read cycle time
+ - gpmc,wr-cycle:	Total write cycle time
+
+The following are only applicable to OMAP3+ and AM335x:
+ - gpmc,wr-access
+ - gpmc,wr-data-mux-bus
+
+
+Example for an AM33xx board:
+
+	gpmc: gpmc at 50000000 {
+		compatible = "ti,gpmc";
+		ti,hwmods = "gpmc";
+		reg = <0x50000000 0x2000>;
+		interrupts = <100>;
+
+		num-cs = <8>;
+		num-waitpins = <2>;
+		#address-cells = <2>;
+		#size-cells = <1>;
+		ranges = <0 0 0x08000000 0x10000000>; /* CS0 @addr 0x8000000, size 0x10000000 */
+
+		/* child nodes go here */
+	};
diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
new file mode 100644
index 0000000..b3fafb1
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
@@ -0,0 +1,76 @@
+Device tree bindings for GPMC connected NANDs
+
+GPMC connected NAND (found on OMAP boards) are represented as child nodes of
+the GPMC controller with a name of "nand".
+
+All timing relevant properties as well as generic gpmc child properties are
+explained in a separate documents - please refer to
+Documentation/devicetree/bindings/bus/ti-gpmc.txt
+
+For NAND specific properties such as ECC modes or bus width, please refer to
+Documentation/devicetree/bindings/mtd/nand.txt
+
+
+Required properties:
+
+ - reg:		The CS line the peripheral is connected to
+
+Optional properties:
+
+ - nand-bus-width: 		Set this numeric value to 16 if the hardware
+				is wired that way. If not specified, a bus
+				width of 8 is assumed.
+
+ - ti,nand-ecc-opt:		A string setting the ECC layout to use. One of:
+
+		"sw"		Software method (default)
+		"hw"		Hardware method
+		"hw-romcode"	gpmc hamming mode method & romcode layout
+		"bch4"		4-bit BCH ecc code
+		"bch8"		8-bit BCH ecc code
+
+For inline partiton table parsing (optional):
+
+ - #address-cells: should be set to 1
+ - #size-cells: should be set to 1
+
+Example for an AM33xx board:
+
+	gpmc: gpmc at 50000000 {
+		compatible = "ti,gpmc";
+		ti,hwmods = "gpmc";
+		reg = <0x50000000 0x1000000>;
+		interrupts = <100>;
+		num-cs = <8>;
+		num-waitpins = <2>;
+		#address-cells = <2>;
+		#size-cells = <1>;
+		ranges = <0 0 0x08000000 0x2000>;	/* CS0: NAND */
+
+		nand at 0,0 {
+			reg = <0 0 0>; /* CS0, offset 0 */
+			nand-bus-width = <16>;
+			ti,nand-ecc-opt = "bch8";
+
+			gpmc,sync-clk = <0>;
+			gpmc,cs-on = <0>;
+			gpmc,cs-rd-off = <44>;
+			gpmc,cs-wr-off = <44>;
+			gpmc,adv-on = <6>;
+			gpmc,adv-rd-off = <34>;
+			gpmc,adv-wr-off = <44>;
+			gpmc,we-off = <40>;
+			gpmc,oe-off = <54>;
+			gpmc,access = <64>;
+			gpmc,rd-cycle = <82>;
+			gpmc,wr-cycle = <82>;
+			gpmc,wr-access = <40>;
+			gpmc,wr-data-mux-bus = <0>;
+
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			/* partitions go here */
+		};
+	};
+
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index d5cbd29..0baf9df 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -25,6 +25,10 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_mtd.h>
+#include <linux/of_device.h>
+#include <linux/mtd/nand.h>
 
 #include <linux/platform_data/mtd-nand-omap2.h>
 
@@ -34,6 +38,7 @@
 #include "common.h"
 #include "omap_device.h"
 #include "gpmc.h"
+#include "gpmc-nand.h"
 
 #define	DEVICE_NAME		"omap-gpmc"
 
@@ -1121,7 +1126,162 @@ int gpmc_calc_timings(struct gpmc_timings *gpmc_t,
 	return 0;
 }
 
-static __devinit int gpmc_probe(struct platform_device *pdev)
+#ifdef CONFIG_OF
+static struct of_device_id gpmc_dt_ids[] = {
+	{ .compatible = "ti,gpmc" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, gpmc_dt_ids);
+
+static void __maybe_unused gpmc_read_timings_dt(struct device_node *np,
+						struct gpmc_timings *gpmc_t)
+{
+	u32 val;
+
+	memset(gpmc_t, 0, sizeof(*gpmc_t));
+
+	/* minimum clock period for syncronous mode */
+	if (!of_property_read_u32(np, "gpmc,sync-clk", &val))
+		gpmc_t->sync_clk = val;
+
+	/* chip select timtings */
+	if (!of_property_read_u32(np, "gpmc,cs-on", &val))
+		gpmc_t->cs_on = val;
+
+	if (!of_property_read_u32(np, "gpmc,cs-rd-off", &val))
+		gpmc_t->cs_rd_off = val;
+
+	if (!of_property_read_u32(np, "gpmc,cs-wr-off", &val))
+		gpmc_t->cs_wr_off = val;
+
+	/* ADV signal timings */
+	if (!of_property_read_u32(np, "gpmc,adv-on", &val))
+		gpmc_t->adv_on = val;
+
+	if (!of_property_read_u32(np, "gpmc,adv-rd-off", &val))
+		gpmc_t->adv_rd_off = val;
+
+	if (!of_property_read_u32(np, "gpmc,adv-wr-off", &val))
+		gpmc_t->adv_wr_off = val;
+
+	/* WE signal timings */
+	if (!of_property_read_u32(np, "gpmc,we-on", &val))
+		gpmc_t->we_on = val;
+
+	if (!of_property_read_u32(np, "gpmc,we-off", &val))
+		gpmc_t->we_off = val;
+
+	/* OE signal timings */
+	if (!of_property_read_u32(np, "gpmc,oe-on", &val))
+		gpmc_t->oe_on = val;
+
+	if (!of_property_read_u32(np, "gpmc,oe-off", &val))
+		gpmc_t->oe_off = val;
+
+	/* access and cycle timings */
+	if (!of_property_read_u32(np, "gpmc,page-burst-access", &val))
+		gpmc_t->page_burst_access = val;
+
+	if (!of_property_read_u32(np, "gpmc,access", &val))
+		gpmc_t->access = val;
+
+	if (!of_property_read_u32(np, "gpmc,rd-cycle", &val))
+		gpmc_t->rd_cycle = val;
+
+	if (!of_property_read_u32(np, "gpmc,wr-cycle", &val))
+		gpmc_t->wr_cycle = val;
+
+	/* only for OMAP3430 */
+	if (!of_property_read_u32(np, "gpmc,wr-access", &val))
+		gpmc_t->wr_access = val;
+
+	if (!of_property_read_u32(np, "gpmc,wr-data-mux-bus", &val))
+		gpmc_t->wr_data_mux_bus = val;
+}
+
+#ifdef CONFIG_MTD_NAND
+
+static const char * const nand_ecc_opts[] = {
+	[OMAP_ECC_HAMMING_CODE_DEFAULT]		= "sw",
+	[OMAP_ECC_HAMMING_CODE_HW]		= "hw",
+	[OMAP_ECC_HAMMING_CODE_HW_ROMCODE]	= "hw-romcode",
+	[OMAP_ECC_BCH4_CODE_HW]			= "bch4",
+	[OMAP_ECC_BCH8_CODE_HW]			= "bch8",
+};
+
+static int gpmc_probe_nand_child(struct platform_device *pdev,
+				 struct device_node *child)
+{
+	u32 val;
+	const char *s;
+	struct gpmc_timings gpmc_t;
+	struct omap_nand_platform_data *gpmc_nand_data;
+
+	if (of_property_read_u32(child, "reg", &val) < 0) {
+		dev_err(&pdev->dev, "%s has no 'reg' property\n",
+			child->full_name);
+		return -ENODEV;
+	}
+
+	gpmc_nand_data = devm_kzalloc(&pdev->dev, sizeof(*gpmc_nand_data),
+				      GFP_KERNEL);
+	if (!gpmc_nand_data)
+		return -ENOMEM;
+
+	gpmc_nand_data->cs = val;
+	gpmc_nand_data->of_node = child;
+
+	if (!of_property_read_string(child, "ti,nand-ecc-opt", &s))
+		for (val = 0; val < ARRAY_SIZE(nand_ecc_opts); val++)
+			if (!strcasecmp(s, nand_ecc_opts[val])) {
+				gpmc_nand_data->ecc_opt = val;
+				break;
+			}
+
+	val = of_get_nand_bus_width(child);
+	if (val == 16)
+		gpmc_nand_data->devsize = NAND_BUSWIDTH_16;
+
+	gpmc_read_timings_dt(child, &gpmc_t);
+	gpmc_nand_init(gpmc_nand_data, &gpmc_t);
+
+	return 0;
+}
+#else
+static int gpmc_probe_nand_child(struct platform_device *pdev,
+				 struct device_node *child)
+{
+	return 0;
+}
+#endif
+
+static int gpmc_probe_dt(struct platform_device *pdev)
+{
+	int ret;
+	struct device_node *child;
+	const struct of_device_id *of_id =
+		of_match_device(gpmc_dt_ids, &pdev->dev);
+
+	if (!of_id)
+		return 0;
+
+	for_each_node_by_name(child, "nand") {
+		ret = gpmc_probe_nand_child(pdev, child);
+		of_node_put(child);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+#else
+static int gpmc_probe_dt(struct platform_device *pdev)
+{
+	return 0;
+}
+#endif
+
+static int __devinit gpmc_probe(struct platform_device *pdev)
 {
 	int rc;
 	u32 l;
@@ -1174,6 +1334,14 @@ static __devinit int gpmc_probe(struct platform_device *pdev)
 	if (IS_ERR_VALUE(gpmc_setup_irq()))
 		dev_warn(gpmc_dev, "gpmc_setup_irq failed\n");
 
+	rc = gpmc_probe_dt(pdev);
+	if (rc < 0) {
+		clk_disable_unprepare(gpmc_l3_clk);
+		clk_put(gpmc_l3_clk);
+		dev_err(gpmc_dev, "failed to probe DT parameters\n");
+		return rc;
+	}
+
 	return 0;
 }
 
@@ -1191,6 +1359,7 @@ static struct platform_driver gpmc_driver = {
 	.driver		= {
 		.name	= DEVICE_NAME,
 		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(gpmc_dt_ids),
 	},
 };
 
-- 
1.7.11.7

[PATCH v7 0/5] OMAP GPMC DT bindings

[Jon Hunter]

On 12/05/2012 01:09 PM, Daniel Mack wrote:
> This is a series of patches to support GPMC peripherals on OMAP boards.
> 
> Grant, Rob, could you have a look and give your Acked-by if
> appropriate?
> 
> 
> Many thanks again,
> Daniel
> 
> 
> Tested on Linus' master +
> omap-next (branch omap-for-v3.8/cleanup-headers-gpmc)
> 
> Generated from linux-next as of today, resolving one trivial include
> file rebase conflict.
> 
> The only supported peripheral for now is NAND, but other types would be
> easy to add.
> 
> Version 2 addresses details pointed out by Jon Hunter, Afzal Mohammed
> and Rob Herring:
> 
>  - add "reg" and "ti,hwmod" properties to Documentation
>  - use generic of_mtd functions and the property names defined by them,
>    namely "nand-bus-width" and "nand-ecc-mode"
>  - reduce the default register space size in the Documentation to 8K,
>    as found in the hwmod code
>  - switch to a DT layout based on ranges and address translation.
>    Although this property is not currently looked at as long as the
>    handling code still uses the runtime calculation methods, we now
>    have these values in the bindings, eventually allowing us to
>    switch the implementation with less pain.
> 
> Version 3 includes fixes pointed out by Jon Hunter:
> 
>  - better documentation of the 'ranges' property to describe the
>    fact that it's representing the CS lines
>  - GPMC_CS_CONFIGx -> GPMC_CONFIGx in comments
>  - drop interrupt-parent from example bindings
>  - add of_node_put() at the end of the child iteration
> 
> Version 4 fixes compilation for !CONFIG_MTD_NAND and includes more
> details from Jon Hunter and Avinash, Philip:
> 
>  - Add "num-cs" and "num-waitpins" properties, which will eventually
>    be used to get rid of GPMC_CS_NUM
>  - Better description of generic nand DT properties
>  - Dropped patch 3/4 as an equivalent fix was already merged
>  - Added ti,nand-ecc-use-elm property
> 
> Version 5 with regards to Avinash, Philip and Peter Korsgaard:
> 
>  - Re-add accidentially forgotten
>    Documentation/devicetree/bindings/bus/ti-gpmc.txt
>  - Rename "software" ecc mode to "sw"
>  - Initialize gpmc_nand_data->is_elm_used to 'true' rather than 1
>  - Drop ti,nand-ecc-use-elm binding in favor of a new ecc mode
>    named "bch8-am335xrbl-compatible"
>  - Add two more patches for section mismatch fixups
> 
> Version 6:
> 
>  - Dropped "bch8-am335xrbl-compatible" mode again. As discussed with
>    Avinash, the ELM issue will be solved subsequently in s separate
>    series.
>  - re-added a patch to bail out of automatic GPMC instanciation in
>    case of DT boot.
>  - re-added the "of_node" addition in mtd_nand_omap2.h in 2/5
> 
> Version 7: comments from Jon Hunter, all affecting the documentation:
> 
>  - add num-wait pins properties as they are marked 'required'
>  - make reg sizes consistent
>  - AM335x only has 2 wait-pins
> 
> Again, many thanks to everybody, in particular Avinash, for the long
> disussion about how to the these details right in the first place.
> 
> 
> Daniel
> 
> Daniel Mack (5):
>   ARM: OMAP: gpmc: don't create devices from initcall on DT
>   mtd: omap-nand: pass device_node in platform data
>   ARM: OMAP: gpmc-nand: drop __init annotation
>   ARM: OMAP: gpmc: enable hwecc for AM33xx SoCs

Do you still need patch #4 now? Can't we drop this?

May be worth just including what is required for linux-next as this is
3.9 material.

Cheers
Jon

[PATCH v7 0/5] OMAP GPMC DT bindings

[Daniel Mack]

On 05.12.2012 20:22, Jon Hunter wrote:
> 
> On 12/05/2012 01:09 PM, Daniel Mack wrote:
>> This is a series of patches to support GPMC peripherals on OMAP boards.
>>
>> Grant, Rob, could you have a look and give your Acked-by if
>> appropriate?
>>
>>
>> Many thanks again,
>> Daniel
>>
>>
>> Tested on Linus' master +
>> omap-next (branch omap-for-v3.8/cleanup-headers-gpmc)
>>
>> Generated from linux-next as of today, resolving one trivial include
>> file rebase conflict.
>>
>> The only supported peripheral for now is NAND, but other types would be
>> easy to add.
>>
>> Version 2 addresses details pointed out by Jon Hunter, Afzal Mohammed
>> and Rob Herring:
>>
>>  - add "reg" and "ti,hwmod" properties to Documentation
>>  - use generic of_mtd functions and the property names defined by them,
>>    namely "nand-bus-width" and "nand-ecc-mode"
>>  - reduce the default register space size in the Documentation to 8K,
>>    as found in the hwmod code
>>  - switch to a DT layout based on ranges and address translation.
>>    Although this property is not currently looked at as long as the
>>    handling code still uses the runtime calculation methods, we now
>>    have these values in the bindings, eventually allowing us to
>>    switch the implementation with less pain.
>>
>> Version 3 includes fixes pointed out by Jon Hunter:
>>
>>  - better documentation of the 'ranges' property to describe the
>>    fact that it's representing the CS lines
>>  - GPMC_CS_CONFIGx -> GPMC_CONFIGx in comments
>>  - drop interrupt-parent from example bindings
>>  - add of_node_put() at the end of the child iteration
>>
>> Version 4 fixes compilation for !CONFIG_MTD_NAND and includes more
>> details from Jon Hunter and Avinash, Philip:
>>
>>  - Add "num-cs" and "num-waitpins" properties, which will eventually
>>    be used to get rid of GPMC_CS_NUM
>>  - Better description of generic nand DT properties
>>  - Dropped patch 3/4 as an equivalent fix was already merged
>>  - Added ti,nand-ecc-use-elm property
>>
>> Version 5 with regards to Avinash, Philip and Peter Korsgaard:
>>
>>  - Re-add accidentially forgotten
>>    Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>  - Rename "software" ecc mode to "sw"
>>  - Initialize gpmc_nand_data->is_elm_used to 'true' rather than 1
>>  - Drop ti,nand-ecc-use-elm binding in favor of a new ecc mode
>>    named "bch8-am335xrbl-compatible"
>>  - Add two more patches for section mismatch fixups
>>
>> Version 6:
>>
>>  - Dropped "bch8-am335xrbl-compatible" mode again. As discussed with
>>    Avinash, the ELM issue will be solved subsequently in s separate
>>    series.
>>  - re-added a patch to bail out of automatic GPMC instanciation in
>>    case of DT boot.
>>  - re-added the "of_node" addition in mtd_nand_omap2.h in 2/5
>>
>> Version 7: comments from Jon Hunter, all affecting the documentation:
>>
>>  - add num-wait pins properties as they are marked 'required'
>>  - make reg sizes consistent
>>  - AM335x only has 2 wait-pins
>>
>> Again, many thanks to everybody, in particular Avinash, for the long
>> disussion about how to the these details right in the first place.
>>
>>
>> Daniel
>>
>> Daniel Mack (5):
>>   ARM: OMAP: gpmc: don't create devices from initcall on DT
>>   mtd: omap-nand: pass device_node in platform data
>>   ARM: OMAP: gpmc-nand: drop __init annotation
>>   ARM: OMAP: gpmc: enable hwecc for AM33xx SoCs
> 
> Do you still need patch #4 now? Can't we drop this?
> 
> May be worth just including what is required for linux-next as this is
> 3.9 material.

Well, yes, otherwise the driver init will bail of course, so I need it
locally.

Feel free to drop it when that's not needed at the time of merging the
series, but for now I resubmitted everything you need to test and use
these patches :)


Daniel

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Grant Likely]

On Wed,  5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@gmail.com> wrote:
> This patch adds basic DT bindings for OMAP GPMC.
> 
> The actual peripherals are instantiated from child nodes within the GPMC
> node, and the only type of device that is currently supported is NAND.
> 
> Code was added to parse the generic GPMC timing parameters and some
> documentation with examples on how to use them.
> 
> Successfully tested on an AM33xx board.
> 
> Signed-off-by: Daniel Mack <zonque@gmail.com>
> ---
>  Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  77 ++++++++++
>  .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
>  arch/arm/mach-omap2/gpmc.c                         | 171 ++++++++++++++++++++-
>  3 files changed, 323 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
>  create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt
> 
> diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
> new file mode 100644
> index 0000000..7d2a645
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
> @@ -0,0 +1,77 @@
> +Device tree bindings for OMAP general purpose memory controllers (GPMC)
> +
> +The actual devices are instantiated from the child nodes of a GPMC node.
> +
> +Required properties:
> +
> + - compatible:		Should be set to "ti,gpmc"

Please, be specific. Use something like "ti,am3340-gpmc" or
"ti,omap3430-gpmc". The compatible property is a list so that new
devices can claim compatibility with old. Compatible strings that are
overly generic are a pet-peave of mine.

> + - reg:			A resource specifier for the register space
> +			(see the example below)
> + - ti,hwmods:		Should be set to "ti,gpmc" until the DT transition is
> +			completed.
> + - #address-cells:	Must be set to 2 to allow memory address translation
> + - #size-cells:		Must be set to 1 to allow CS address passing
> + - num-cs:		The maximum number of chip-select lines that controller
> +			can support.

gpmc,num-cs

> + - num-waitpins:	The maximum number of wait pins that controller can
> +			support.

gpmc,num-waitpins

> + - ranges:		Must be set up to reflect the memory layout with four
> +			integer values for each chip-select line in use:
> +
> +			   <cs-number> 0 <physical address of mapping> <size>
> +
> +			Note that this property is not currently parsed.
> +			Calculated values derived from the contents of the
> +			per-CS register GPMC_CONFIG7 (as set up by the
> +			bootloader) are used. That will change in the future,
> +			so be sure to fill the correct values here.

The core linux code will use ranges to decode the reg property of child
devices, even if the gpmc driver doesn't use it, so the comment here is
misleading.

Otherwise the binding looks fine to me.

> diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
> new file mode 100644
> index 0000000..b3fafb1
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
> @@ -0,0 +1,76 @@
> +Device tree bindings for GPMC connected NANDs
> +
> +GPMC connected NAND (found on OMAP boards) are represented as child nodes of
> +the GPMC controller with a name of "nand".
> +
> +All timing relevant properties as well as generic gpmc child properties are
> +explained in a separate documents - please refer to
> +Documentation/devicetree/bindings/bus/ti-gpmc.txt
> +
> +For NAND specific properties such as ECC modes or bus width, please refer to
> +Documentation/devicetree/bindings/mtd/nand.txt
> +
> +
> +Required properties:
> +
> + - reg:		The CS line the peripheral is connected to
> +
> +Optional properties:
> +
> + - nand-bus-width: 		Set this numeric value to 16 if the hardware
> +				is wired that way. If not specified, a bus
> +				width of 8 is assumed.
> +
> + - ti,nand-ecc-opt:		A string setting the ECC layout to use. One of:
> +
> +		"sw"		Software method (default)
> +		"hw"		Hardware method
> +		"hw-romcode"	gpmc hamming mode method & romcode layout
> +		"bch4"		4-bit BCH ecc code
> +		"bch8"		8-bit BCH ecc code
> +
> +For inline partiton table parsing (optional):
> +
> + - #address-cells: should be set to 1
> + - #size-cells: should be set to 1
> +
> +Example for an AM33xx board:
> +
> +	gpmc: gpmc at 50000000 {
> +		compatible = "ti,gpmc";
> +		ti,hwmods = "gpmc";
> +		reg = <0x50000000 0x1000000>;
> +		interrupts = <100>;
> +		num-cs = <8>;
> +		num-waitpins = <2>;
> +		#address-cells = <2>;
> +		#size-cells = <1>;
> +		ranges = <0 0 0x08000000 0x2000>;	/* CS0: NAND */
> +
> +		nand at 0,0 {
> +			reg = <0 0 0>; /* CS0, offset 0 */
> +			nand-bus-width = <16>;
> +			ti,nand-ecc-opt = "bch8";
> +
> +			gpmc,sync-clk = <0>;
> +			gpmc,cs-on = <0>;
> +			gpmc,cs-rd-off = <44>;
> +			gpmc,cs-wr-off = <44>;
> +			gpmc,adv-on = <6>;
> +			gpmc,adv-rd-off = <34>;
> +			gpmc,adv-wr-off = <44>;
> +			gpmc,we-off = <40>;
> +			gpmc,oe-off = <54>;
> +			gpmc,access = <64>;
> +			gpmc,rd-cycle = <82>;
> +			gpmc,wr-cycle = <82>;
> +			gpmc,wr-access = <40>;
> +			gpmc,wr-data-mux-bus = <0>;
> +
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +
> +			/* partitions go here */
> +		};
> +	};
> +
> diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
> index d5cbd29..0baf9df 100644
> --- a/arch/arm/mach-omap2/gpmc.c
> +++ b/arch/arm/mach-omap2/gpmc.c
> @@ -25,6 +25,10 @@
>  #include <linux/module.h>
>  #include <linux/interrupt.h>
>  #include <linux/platform_device.h>
> +#include <linux/of.h>
> +#include <linux/of_mtd.h>
> +#include <linux/of_device.h>
> +#include <linux/mtd/nand.h>
>  
>  #include <linux/platform_data/mtd-nand-omap2.h>
>  
> @@ -34,6 +38,7 @@
>  #include "common.h"
>  #include "omap_device.h"
>  #include "gpmc.h"
> +#include "gpmc-nand.h"
>  
>  #define	DEVICE_NAME		"omap-gpmc"
>  
> @@ -1121,7 +1126,162 @@ int gpmc_calc_timings(struct gpmc_timings *gpmc_t,
>  	return 0;
>  }
>  
> -static __devinit int gpmc_probe(struct platform_device *pdev)
> +#ifdef CONFIG_OF
> +static struct of_device_id gpmc_dt_ids[] = {
> +	{ .compatible = "ti,gpmc" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, gpmc_dt_ids);
> +
> +static void __maybe_unused gpmc_read_timings_dt(struct device_node *np,
> +						struct gpmc_timings *gpmc_t)
> +{
> +	u32 val;
> +
> +	memset(gpmc_t, 0, sizeof(*gpmc_t));
> +
> +	/* minimum clock period for syncronous mode */
> +	if (!of_property_read_u32(np, "gpmc,sync-clk", &val))
> +		gpmc_t->sync_clk = val;
> +
> +	/* chip select timtings */
> +	if (!of_property_read_u32(np, "gpmc,cs-on", &val))
> +		gpmc_t->cs_on = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,cs-rd-off", &val))
> +		gpmc_t->cs_rd_off = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,cs-wr-off", &val))
> +		gpmc_t->cs_wr_off = val;
> +
> +	/* ADV signal timings */
> +	if (!of_property_read_u32(np, "gpmc,adv-on", &val))
> +		gpmc_t->adv_on = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,adv-rd-off", &val))
> +		gpmc_t->adv_rd_off = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,adv-wr-off", &val))
> +		gpmc_t->adv_wr_off = val;
> +
> +	/* WE signal timings */
> +	if (!of_property_read_u32(np, "gpmc,we-on", &val))
> +		gpmc_t->we_on = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,we-off", &val))
> +		gpmc_t->we_off = val;
> +
> +	/* OE signal timings */
> +	if (!of_property_read_u32(np, "gpmc,oe-on", &val))
> +		gpmc_t->oe_on = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,oe-off", &val))
> +		gpmc_t->oe_off = val;
> +
> +	/* access and cycle timings */
> +	if (!of_property_read_u32(np, "gpmc,page-burst-access", &val))
> +		gpmc_t->page_burst_access = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,access", &val))
> +		gpmc_t->access = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,rd-cycle", &val))
> +		gpmc_t->rd_cycle = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,wr-cycle", &val))
> +		gpmc_t->wr_cycle = val;
> +
> +	/* only for OMAP3430 */
> +	if (!of_property_read_u32(np, "gpmc,wr-access", &val))
> +		gpmc_t->wr_access = val;
> +
> +	if (!of_property_read_u32(np, "gpmc,wr-data-mux-bus", &val))
> +		gpmc_t->wr_data_mux_bus = val;
> +}
> +
> +#ifdef CONFIG_MTD_NAND
> +
> +static const char * const nand_ecc_opts[] = {
> +	[OMAP_ECC_HAMMING_CODE_DEFAULT]		= "sw",
> +	[OMAP_ECC_HAMMING_CODE_HW]		= "hw",
> +	[OMAP_ECC_HAMMING_CODE_HW_ROMCODE]	= "hw-romcode",
> +	[OMAP_ECC_BCH4_CODE_HW]			= "bch4",
> +	[OMAP_ECC_BCH8_CODE_HW]			= "bch8",
> +};
> +
> +static int gpmc_probe_nand_child(struct platform_device *pdev,
> +				 struct device_node *child)
> +{
> +	u32 val;
> +	const char *s;
> +	struct gpmc_timings gpmc_t;
> +	struct omap_nand_platform_data *gpmc_nand_data;
> +
> +	if (of_property_read_u32(child, "reg", &val) < 0) {
> +		dev_err(&pdev->dev, "%s has no 'reg' property\n",
> +			child->full_name);
> +		return -ENODEV;
> +	}
> +
> +	gpmc_nand_data = devm_kzalloc(&pdev->dev, sizeof(*gpmc_nand_data),
> +				      GFP_KERNEL);
> +	if (!gpmc_nand_data)
> +		return -ENOMEM;
> +
> +	gpmc_nand_data->cs = val;
> +	gpmc_nand_data->of_node = child;
> +
> +	if (!of_property_read_string(child, "ti,nand-ecc-opt", &s))
> +		for (val = 0; val < ARRAY_SIZE(nand_ecc_opts); val++)
> +			if (!strcasecmp(s, nand_ecc_opts[val])) {
> +				gpmc_nand_data->ecc_opt = val;
> +				break;
> +			}
> +
> +	val = of_get_nand_bus_width(child);
> +	if (val == 16)
> +		gpmc_nand_data->devsize = NAND_BUSWIDTH_16;
> +
> +	gpmc_read_timings_dt(child, &gpmc_t);
> +	gpmc_nand_init(gpmc_nand_data, &gpmc_t);
> +
> +	return 0;
> +}
> +#else
> +static int gpmc_probe_nand_child(struct platform_device *pdev,
> +				 struct device_node *child)
> +{
> +	return 0;
> +}
> +#endif
> +
> +static int gpmc_probe_dt(struct platform_device *pdev)
> +{
> +	int ret;
> +	struct device_node *child;
> +	const struct of_device_id *of_id =
> +		of_match_device(gpmc_dt_ids, &pdev->dev);
> +
> +	if (!of_id)
> +		return 0;
> +
> +	for_each_node_by_name(child, "nand") {
> +		ret = gpmc_probe_nand_child(pdev, child);
> +		of_node_put(child);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +#else
> +static int gpmc_probe_dt(struct platform_device *pdev)
> +{
> +	return 0;
> +}
> +#endif
> +
> +static int __devinit gpmc_probe(struct platform_device *pdev)
>  {
>  	int rc;
>  	u32 l;
> @@ -1174,6 +1334,14 @@ static __devinit int gpmc_probe(struct platform_device *pdev)
>  	if (IS_ERR_VALUE(gpmc_setup_irq()))
>  		dev_warn(gpmc_dev, "gpmc_setup_irq failed\n");
>  
> +	rc = gpmc_probe_dt(pdev);
> +	if (rc < 0) {
> +		clk_disable_unprepare(gpmc_l3_clk);
> +		clk_put(gpmc_l3_clk);
> +		dev_err(gpmc_dev, "failed to probe DT parameters\n");
> +		return rc;
> +	}
> +
>  	return 0;
>  }
>  
> @@ -1191,6 +1359,7 @@ static struct platform_driver gpmc_driver = {
>  	.driver		= {
>  		.name	= DEVICE_NAME,
>  		.owner	= THIS_MODULE,
> +		.of_match_table = of_match_ptr(gpmc_dt_ids),
>  	},
>  };
>  
> -- 
> 1.7.11.7
> 

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Jon Hunter]

Hi Grant,

On 12/05/2012 04:22 PM, Grant Likely wrote:
> On Wed,  5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@gmail.com> wrote:
>> This patch adds basic DT bindings for OMAP GPMC.
>>
>> The actual peripherals are instantiated from child nodes within the GPMC
>> node, and the only type of device that is currently supported is NAND.
>>
>> Code was added to parse the generic GPMC timing parameters and some
>> documentation with examples on how to use them.
>>
>> Successfully tested on an AM33xx board.
>>
>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>> ---
>>  Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  77 ++++++++++
>>  .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
>>  arch/arm/mach-omap2/gpmc.c                         | 171 ++++++++++++++++++++-
>>  3 files changed, 323 insertions(+), 1 deletion(-)
>>  create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>  create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt
>>
>> diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>> new file mode 100644
>> index 0000000..7d2a645
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>> @@ -0,0 +1,77 @@
>> +Device tree bindings for OMAP general purpose memory controllers (GPMC)
>> +
>> +The actual devices are instantiated from the child nodes of a GPMC node.
>> +
>> +Required properties:
>> +
>> + - compatible:		Should be set to "ti,gpmc"
> 
> Please, be specific. Use something like "ti,am3340-gpmc" or
> "ti,omap3430-gpmc". The compatible property is a list so that new
> devices can claim compatibility with old. Compatible strings that are
> overly generic are a pet-peave of mine.

We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
(which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
implying all omap2+ based devices or should we have a compatible string
for each device supported?

Thanks
Jon

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Grant Likely]

On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
> Hi Grant,
> 
> On 12/05/2012 04:22 PM, Grant Likely wrote:
> > On Wed,  5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@gmail.com> wrote:
> >> This patch adds basic DT bindings for OMAP GPMC.
> >>
> >> The actual peripherals are instantiated from child nodes within the GPMC
> >> node, and the only type of device that is currently supported is NAND.
> >>
> >> Code was added to parse the generic GPMC timing parameters and some
> >> documentation with examples on how to use them.
> >>
> >> Successfully tested on an AM33xx board.
> >>
> >> Signed-off-by: Daniel Mack <zonque@gmail.com>
> >> ---
> >>  Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  77 ++++++++++
> >>  .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
> >>  arch/arm/mach-omap2/gpmc.c                         | 171 ++++++++++++++++++++-
> >>  3 files changed, 323 insertions(+), 1 deletion(-)
> >>  create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
> >>  create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
> >> new file mode 100644
> >> index 0000000..7d2a645
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
> >> @@ -0,0 +1,77 @@
> >> +Device tree bindings for OMAP general purpose memory controllers (GPMC)
> >> +
> >> +The actual devices are instantiated from the child nodes of a GPMC node.
> >> +
> >> +Required properties:
> >> +
> >> + - compatible:		Should be set to "ti,gpmc"
> > 
> > Please, be specific. Use something like "ti,am3340-gpmc" or
> > "ti,omap3430-gpmc". The compatible property is a list so that new
> > devices can claim compatibility with old. Compatible strings that are
> > overly generic are a pet-peave of mine.
> 
> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
> implying all omap2+ based devices or should we have a compatible string
> for each device supported?

Are they each register-level compatible with one another?

The general recommended approach here is to make subsequent silicon
claim compatibility with the first compatible implementation.

So, for an am3358 board:
	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";

Essentially, what this means is that "ti,omap2420-gpmc" is the generic
value instead of "omap2-gpmc". The reason for this is so that the value
is anchored against a specific implementation, and not against something
completely imaginary or idealized. If a newer version isn't quite
compatible with the omap2420-gpmc, then it can drop the compatible claim
and the driver really should be told about the new device.

g.



> 
> Thanks
> Jon
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Tony Lindgren]

* Grant Likely <grant.likely@secretlab.ca> [121205 15:26]:
> On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
> > On 12/05/2012 04:22 PM, Grant Likely wrote:
> > > 
> > > Please, be specific. Use something like "ti,am3340-gpmc" or
> > > "ti,omap3430-gpmc". The compatible property is a list so that new
> > > devices can claim compatibility with old. Compatible strings that are
> > > overly generic are a pet-peave of mine.
> > 
> > We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
> > (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
> > implying all omap2+ based devices or should we have a compatible string
> > for each device supported?
> 
> Are they each register-level compatible with one another?
> 
> The general recommended approach here is to make subsequent silicon
> claim compatibility with the first compatible implementation.
> 
> So, for an am3358 board:
> 	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";
> 
> Essentially, what this means is that "ti,omap2420-gpmc" is the generic
> value instead of "omap2-gpmc". The reason for this is so that the value
> is anchored against a specific implementation, and not against something
> completely imaginary or idealized. If a newer version isn't quite
> compatible with the omap2420-gpmc, then it can drop the compatible claim
> and the driver really should be told about the new device.

The compatible property can also be used to figure out which ones
need the workarounds in patch #4 of this series for the DT case.
So we should be specific with the compatible.

Regards,

Tony

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Jon Hunter]

On 12/05/2012 05:24 PM, Grant Likely wrote:
> On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
>> Hi Grant,
>>
>> On 12/05/2012 04:22 PM, Grant Likely wrote:
>>> On Wed,  5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@gmail.com> wrote:
>>>> This patch adds basic DT bindings for OMAP GPMC.
>>>>
>>>> The actual peripherals are instantiated from child nodes within the GPMC
>>>> node, and the only type of device that is currently supported is NAND.
>>>>
>>>> Code was added to parse the generic GPMC timing parameters and some
>>>> documentation with examples on how to use them.
>>>>
>>>> Successfully tested on an AM33xx board.
>>>>
>>>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>>>> ---
>>>>  Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  77 ++++++++++
>>>>  .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
>>>>  arch/arm/mach-omap2/gpmc.c                         | 171 ++++++++++++++++++++-
>>>>  3 files changed, 323 insertions(+), 1 deletion(-)
>>>>  create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>  create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>> new file mode 100644
>>>> index 0000000..7d2a645
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>> @@ -0,0 +1,77 @@
>>>> +Device tree bindings for OMAP general purpose memory controllers (GPMC)
>>>> +
>>>> +The actual devices are instantiated from the child nodes of a GPMC node.
>>>> +
>>>> +Required properties:
>>>> +
>>>> + - compatible:		Should be set to "ti,gpmc"
>>>
>>> Please, be specific. Use something like "ti,am3340-gpmc" or
>>> "ti,omap3430-gpmc". The compatible property is a list so that new
>>> devices can claim compatibility with old. Compatible strings that are
>>> overly generic are a pet-peave of mine.
>>
>> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
>> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
>> implying all omap2+ based devices or should we have a compatible string
>> for each device supported?
> 
> Are they each register-level compatible with one another?

They are not 100% register compatible. There are a couple fields in the
binding that are only applicable to OMAP3+ devices.

> The general recommended approach here is to make subsequent silicon
> claim compatibility with the first compatible implementation.
> 
> So, for an am3358 board:
> 	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";
> 
> Essentially, what this means is that "ti,omap2420-gpmc" is the generic
> value instead of "omap2-gpmc". The reason for this is so that the value
> is anchored against a specific implementation, and not against something
> completely imaginary or idealized. If a newer version isn't quite
> compatible with the omap2420-gpmc, then it can drop the compatible claim
> and the driver really should be told about the new device.

Ok, gotcha! I will do a register comparison and may be recommend to
Daniel which compatible strings we will need.

Thanks!
Jon

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Jon Hunter]

On 12/05/2012 06:03 PM, Tony Lindgren wrote:
> * Grant Likely <grant.likely@secretlab.ca> [121205 15:26]:
>> On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
>>> On 12/05/2012 04:22 PM, Grant Likely wrote:
>>>>
>>>> Please, be specific. Use something like "ti,am3340-gpmc" or
>>>> "ti,omap3430-gpmc". The compatible property is a list so that new
>>>> devices can claim compatibility with old. Compatible strings that are
>>>> overly generic are a pet-peave of mine.
>>>
>>> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
>>> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
>>> implying all omap2+ based devices or should we have a compatible string
>>> for each device supported?
>>
>> Are they each register-level compatible with one another?
>>
>> The general recommended approach here is to make subsequent silicon
>> claim compatibility with the first compatible implementation.
>>
>> So, for an am3358 board:
>> 	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";
>>
>> Essentially, what this means is that "ti,omap2420-gpmc" is the generic
>> value instead of "omap2-gpmc". The reason for this is so that the value
>> is anchored against a specific implementation, and not against something
>> completely imaginary or idealized. If a newer version isn't quite
>> compatible with the omap2420-gpmc, then it can drop the compatible claim
>> and the driver really should be told about the new device.
> 
> The compatible property can also be used to figure out which ones
> need the workarounds in patch #4 of this series for the DT case.
> So we should be specific with the compatible.

We should not merged patch #4. Daniel included this here because he is
using this on the current mainline, however, this is not needed for
linux-next and so we should drop it.

Cheers
Jon

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Daniel Mack]

On 06.12.2012 17:22, Jon Hunter wrote:
> 
> On 12/05/2012 06:03 PM, Tony Lindgren wrote:
>> * Grant Likely <grant.likely@secretlab.ca> [121205 15:26]:
>>> On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
>>>> On 12/05/2012 04:22 PM, Grant Likely wrote:
>>>>>
>>>>> Please, be specific. Use something like "ti,am3340-gpmc" or
>>>>> "ti,omap3430-gpmc". The compatible property is a list so that new
>>>>> devices can claim compatibility with old. Compatible strings that are
>>>>> overly generic are a pet-peave of mine.
>>>>
>>>> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
>>>> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
>>>> implying all omap2+ based devices or should we have a compatible string
>>>> for each device supported?
>>>
>>> Are they each register-level compatible with one another?
>>>
>>> The general recommended approach here is to make subsequent silicon
>>> claim compatibility with the first compatible implementation.
>>>
>>> So, for an am3358 board:
>>> 	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";
>>>
>>> Essentially, what this means is that "ti,omap2420-gpmc" is the generic
>>> value instead of "omap2-gpmc". The reason for this is so that the value
>>> is anchored against a specific implementation, and not against something
>>> completely imaginary or idealized. If a newer version isn't quite
>>> compatible with the omap2420-gpmc, then it can drop the compatible claim
>>> and the driver really should be told about the new device.
>>
>> The compatible property can also be used to figure out which ones
>> need the workarounds in patch #4 of this series for the DT case.
>> So we should be specific with the compatible.
> 
> We should not merged patch #4. Daniel included this here because he is
> using this on the current mainline, however, this is not needed for
> linux-next and so we should drop it.

I think we're talking about different things here since awhile.

The patch I pointed you which is in mainline and which removes the
reference to <plat/gpmc.h> from drivers/mtd/nand/omap2.c has nothing to
do with my patch #4. It just solves Tony's concern that regarding the
multi-arch zImages.

My code in gpmc.c calls gpmc_nand_init() which in turn calls
gpmc_hwecc_bch_capable(). Without path #4, gpmc_hwecc_bch_capable() will
return 0, and the nand init will fail consequently, in mainline as well
as in linux-next.

I understood Tony that he wanted to remove the entiry function and do
the check based on DT properties, which will then solve the problem on a
different level. However, that change is planned for *after* the merge
window.


Daniel

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Daniel Mack]

Hi Jon,

On 06.12.2012 17:19, Jon Hunter wrote:
> 
> On 12/05/2012 05:24 PM, Grant Likely wrote:
>> On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
>>> Hi Grant,
>>>
>>> On 12/05/2012 04:22 PM, Grant Likely wrote:
>>>> On Wed,  5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@gmail.com> wrote:
>>>>> This patch adds basic DT bindings for OMAP GPMC.
>>>>>
>>>>> The actual peripherals are instantiated from child nodes within the GPMC
>>>>> node, and the only type of device that is currently supported is NAND.
>>>>>
>>>>> Code was added to parse the generic GPMC timing parameters and some
>>>>> documentation with examples on how to use them.
>>>>>
>>>>> Successfully tested on an AM33xx board.
>>>>>
>>>>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>>>>> ---
>>>>>  Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  77 ++++++++++
>>>>>  .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
>>>>>  arch/arm/mach-omap2/gpmc.c                         | 171 ++++++++++++++++++++-
>>>>>  3 files changed, 323 insertions(+), 1 deletion(-)
>>>>>  create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>>  create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>> new file mode 100644
>>>>> index 0000000..7d2a645
>>>>> --- /dev/null
>>>>> +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>> @@ -0,0 +1,77 @@
>>>>> +Device tree bindings for OMAP general purpose memory controllers (GPMC)
>>>>> +
>>>>> +The actual devices are instantiated from the child nodes of a GPMC node.
>>>>> +
>>>>> +Required properties:
>>>>> +
>>>>> + - compatible:		Should be set to "ti,gpmc"
>>>>
>>>> Please, be specific. Use something like "ti,am3340-gpmc" or
>>>> "ti,omap3430-gpmc". The compatible property is a list so that new
>>>> devices can claim compatibility with old. Compatible strings that are
>>>> overly generic are a pet-peave of mine.
>>>
>>> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
>>> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
>>> implying all omap2+ based devices or should we have a compatible string
>>> for each device supported?
>>
>> Are they each register-level compatible with one another?
> 
> They are not 100% register compatible. There are a couple fields in the
> binding that are only applicable to OMAP3+ devices.
> 
>> The general recommended approach here is to make subsequent silicon
>> claim compatibility with the first compatible implementation.
>>
>> So, for an am3358 board:
>> 	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";
>>
>> Essentially, what this means is that "ti,omap2420-gpmc" is the generic
>> value instead of "omap2-gpmc". The reason for this is so that the value
>> is anchored against a specific implementation, and not against something
>> completely imaginary or idealized. If a newer version isn't quite
>> compatible with the omap2420-gpmc, then it can drop the compatible claim
>> and the driver really should be told about the new device.
> 
> Ok, gotcha! I will do a register comparison and may be recommend to
> Daniel which compatible strings we will need.

Ok, thanks a lot!

However, I don't know whether we should treat different models
differently in the code yet, distiguished by their 'compatible' string.

We should register the driver correctly so we can use the power of that
feature once we get rid of the runtime-hacks (cpu_is_xxx() macros), but
I think until we're there, we can well live with multiple
compatible-entries that all map to the same driver, right?

OTOH, we could also think about tieing num-waitpins and num-cs to a
specific 'compatible' entry (by passing a struct along in .data members
of of_device_id), but I'm not sure whether that's really better here.


Daniel

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Jon Hunter]

On 12/06/2012 10:54 AM, Daniel Mack wrote:
> On 06.12.2012 17:22, Jon Hunter wrote:
>>
>> On 12/05/2012 06:03 PM, Tony Lindgren wrote:
>>> * Grant Likely <grant.likely@secretlab.ca> [121205 15:26]:
>>>> On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
>>>>> On 12/05/2012 04:22 PM, Grant Likely wrote:
>>>>>>
>>>>>> Please, be specific. Use something like "ti,am3340-gpmc" or
>>>>>> "ti,omap3430-gpmc". The compatible property is a list so that new
>>>>>> devices can claim compatibility with old. Compatible strings that are
>>>>>> overly generic are a pet-peave of mine.
>>>>>
>>>>> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
>>>>> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
>>>>> implying all omap2+ based devices or should we have a compatible string
>>>>> for each device supported?
>>>>
>>>> Are they each register-level compatible with one another?
>>>>
>>>> The general recommended approach here is to make subsequent silicon
>>>> claim compatibility with the first compatible implementation.
>>>>
>>>> So, for an am3358 board:
>>>> 	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";
>>>>
>>>> Essentially, what this means is that "ti,omap2420-gpmc" is the generic
>>>> value instead of "omap2-gpmc". The reason for this is so that the value
>>>> is anchored against a specific implementation, and not against something
>>>> completely imaginary or idealized. If a newer version isn't quite
>>>> compatible with the omap2420-gpmc, then it can drop the compatible claim
>>>> and the driver really should be told about the new device.
>>>
>>> The compatible property can also be used to figure out which ones
>>> need the workarounds in patch #4 of this series for the DT case.
>>> So we should be specific with the compatible.
>>
>> We should not merged patch #4. Daniel included this here because he is
>> using this on the current mainline, however, this is not needed for
>> linux-next and so we should drop it.
> 
> I think we're talking about different things here since awhile.
> 
> The patch I pointed you which is in mainline and which removes the
> reference to <plat/gpmc.h> from drivers/mtd/nand/omap2.c has nothing to
> do with my patch #4. It just solves Tony's concern that regarding the
> multi-arch zImages.
>
> My code in gpmc.c calls gpmc_nand_init() which in turn calls
> gpmc_hwecc_bch_capable(). Without path #4, gpmc_hwecc_bch_capable() will
> return 0, and the nand init will fail consequently, in mainline as well
> as in linux-next.

Ok, yes I see that now. I should have looked more closely at linux-next.

> I understood Tony that he wanted to remove the entiry function and do
> the check based on DT properties, which will then solve the problem on a
> different level. However, that change is planned for *after* the merge
> window.

Well now that it is only being called from within the platform code and
not from drivers, it is ok.

Cheers
Jon

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Daniel Mack]

On 06.12.2012 17:19, Jon Hunter wrote:
> 
> On 12/05/2012 05:24 PM, Grant Likely wrote:
>> On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
>>> Hi Grant,
>>>
>>> On 12/05/2012 04:22 PM, Grant Likely wrote:
>>>> On Wed,  5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@gmail.com> wrote:
>>>>> This patch adds basic DT bindings for OMAP GPMC.
>>>>>
>>>>> The actual peripherals are instantiated from child nodes within the GPMC
>>>>> node, and the only type of device that is currently supported is NAND.
>>>>>
>>>>> Code was added to parse the generic GPMC timing parameters and some
>>>>> documentation with examples on how to use them.
>>>>>
>>>>> Successfully tested on an AM33xx board.
>>>>>
>>>>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>>>>> ---
>>>>>  Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  77 ++++++++++
>>>>>  .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
>>>>>  arch/arm/mach-omap2/gpmc.c                         | 171 ++++++++++++++++++++-
>>>>>  3 files changed, 323 insertions(+), 1 deletion(-)
>>>>>  create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>>  create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>> new file mode 100644
>>>>> index 0000000..7d2a645
>>>>> --- /dev/null
>>>>> +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>> @@ -0,0 +1,77 @@
>>>>> +Device tree bindings for OMAP general purpose memory controllers (GPMC)
>>>>> +
>>>>> +The actual devices are instantiated from the child nodes of a GPMC node.
>>>>> +
>>>>> +Required properties:
>>>>> +
>>>>> + - compatible:		Should be set to "ti,gpmc"
>>>>
>>>> Please, be specific. Use something like "ti,am3340-gpmc" or
>>>> "ti,omap3430-gpmc". The compatible property is a list so that new
>>>> devices can claim compatibility with old. Compatible strings that are
>>>> overly generic are a pet-peave of mine.
>>>
>>> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
>>> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
>>> implying all omap2+ based devices or should we have a compatible string
>>> for each device supported?
>>
>> Are they each register-level compatible with one another?
> 
> They are not 100% register compatible. There are a couple fields in the
> binding that are only applicable to OMAP3+ devices.
> 
>> The general recommended approach here is to make subsequent silicon
>> claim compatibility with the first compatible implementation.
>>
>> So, for an am3358 board:
>> 	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";
>>
>> Essentially, what this means is that "ti,omap2420-gpmc" is the generic
>> value instead of "omap2-gpmc". The reason for this is so that the value
>> is anchored against a specific implementation, and not against something
>> completely imaginary or idealized. If a newer version isn't quite
>> compatible with the omap2420-gpmc, then it can drop the compatible claim
>> and the driver really should be told about the new device.
> 
> Ok, gotcha! I will do a register comparison and may be recommend to
> Daniel which compatible strings we will need.

Any idea yet how we want to continue on this? I'm asking because I'm
leaving for a longer trip by the end of this week, and so anything I
haven't finished until then will have to be postponed until February or
be taken over by someone else :)

Thanks,
Daniel

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Jon Hunter]

On 12/12/2012 03:13 AM, Daniel Mack wrote:
> On 06.12.2012 17:19, Jon Hunter wrote:
>>
>> On 12/05/2012 05:24 PM, Grant Likely wrote:
>>> On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
>>>> Hi Grant,
>>>>
>>>> On 12/05/2012 04:22 PM, Grant Likely wrote:
>>>>> On Wed,  5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@gmail.com> wrote:
>>>>>> This patch adds basic DT bindings for OMAP GPMC.
>>>>>>
>>>>>> The actual peripherals are instantiated from child nodes within the GPMC
>>>>>> node, and the only type of device that is currently supported is NAND.
>>>>>>
>>>>>> Code was added to parse the generic GPMC timing parameters and some
>>>>>> documentation with examples on how to use them.
>>>>>>
>>>>>> Successfully tested on an AM33xx board.
>>>>>>
>>>>>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>>>>>> ---
>>>>>>  Documentation/devicetree/bindings/bus/ti-gpmc.txt  |  77 ++++++++++
>>>>>>  .../devicetree/bindings/mtd/gpmc-nand.txt          |  76 +++++++++
>>>>>>  arch/arm/mach-omap2/gpmc.c                         | 171 ++++++++++++++++++++-
>>>>>>  3 files changed, 323 insertions(+), 1 deletion(-)
>>>>>>  create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>>>  create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>>> new file mode 100644
>>>>>> index 0000000..7d2a645
>>>>>> --- /dev/null
>>>>>> +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt
>>>>>> @@ -0,0 +1,77 @@
>>>>>> +Device tree bindings for OMAP general purpose memory controllers (GPMC)
>>>>>> +
>>>>>> +The actual devices are instantiated from the child nodes of a GPMC node.
>>>>>> +
>>>>>> +Required properties:
>>>>>> +
>>>>>> + - compatible:		Should be set to "ti,gpmc"
>>>>>
>>>>> Please, be specific. Use something like "ti,am3340-gpmc" or
>>>>> "ti,omap3430-gpmc". The compatible property is a list so that new
>>>>> devices can claim compatibility with old. Compatible strings that are
>>>>> overly generic are a pet-peave of mine.
>>>>
>>>> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices
>>>> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc"
>>>> implying all omap2+ based devices or should we have a compatible string
>>>> for each device supported?
>>>
>>> Are they each register-level compatible with one another?
>>
>> They are not 100% register compatible. There are a couple fields in the
>> binding that are only applicable to OMAP3+ devices.
>>
>>> The general recommended approach here is to make subsequent silicon
>>> claim compatibility with the first compatible implementation.
>>>
>>> So, for an am3358 board:
>>> 	compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc";
>>>
>>> Essentially, what this means is that "ti,omap2420-gpmc" is the generic
>>> value instead of "omap2-gpmc". The reason for this is so that the value
>>> is anchored against a specific implementation, and not against something
>>> completely imaginary or idealized. If a newer version isn't quite
>>> compatible with the omap2420-gpmc, then it can drop the compatible claim
>>> and the driver really should be told about the new device.
>>
>> Ok, gotcha! I will do a register comparison and may be recommend to
>> Daniel which compatible strings we will need.
> 
> Any idea yet how we want to continue on this? I'm asking because I'm
> leaving for a longer trip by the end of this week, and so anything I
> haven't finished until then will have to be postponed until February or
> be taken over by someone else :)

Thanks for the reminder!

So looking at this today, here is what I see when comparing the
registers ...

omap2430 != omap2420
omap3430 != omap2430
omap3630 == omap3430
omap4430 != omap3430
omap4460 == omap4430
omap543x == omap4430
am335x != omap4430

Therefore, I believe that we need to have the following compatible
strings ...

ti,omap2420-gpmc
ti,omap2430-gpmc
ti,omap3430-gpmc (omap3430 & omap3630)
ti,omap4430-gpmc (omap4430 & omap4460 & omap543x)
ti,am3352-gpmc (am335x devices)

Probably worth adding a comment to the Documentation what should be used
for which device.

Cheers
Jon

[PATCH v7 5/5] ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

[Grant Likely]

On Wed, 12 Dec 2012 17:02:10 -0600, Jon Hunter <jon-hunter@ti.com> wrote:
> 
> So looking at this today, here is what I see when comparing the
> registers ...
> 
> omap2430 != omap2420
> omap3430 != omap2430
> omap3630 == omap3430
> omap4430 != omap3430
> omap4460 == omap4430
> omap543x == omap4430
> am335x != omap4430
> 
> Therefore, I believe that we need to have the following compatible
> strings ...
> 
> ti,omap2420-gpmc
> ti,omap2430-gpmc
> ti,omap3430-gpmc (omap3430 & omap3630)
> ti,omap4430-gpmc (omap4430 & omap4460 & omap543x)
> ti,am3352-gpmc (am335x devices)
> 
> Probably worth adding a comment to the Documentation what should be used
> for which device.

Yes, it is completely appropriate to add a comment to the documentation
here so this doesn't get lost.

g.