| Message ID | 20181003193859.23928-7-ricardo.ribalda@gmail.com |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | None | expand |
On Wed, 3 Oct 2018 21:38:58 +0200 Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > Add documentation for gpio-addr-flash. This binding allow creating > flash devices that are paged using GPIOs. > > Cc: devicetree@vger.kernel.org > Reviewed-by: Rob Herring <robh@kernel.org> > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> > --- > .../bindings/mtd/gpio-addr-flash.txt | 54 +++++++++++++++++++ > 1 file changed, 54 insertions(+) > create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > new file mode 100644 > index 000000000000..5006a26e1753 > --- /dev/null > +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > @@ -0,0 +1,54 @@ > +Memory Mapped flash with some address lines addressed using GPIOs > + > +Handle the case where a flash device is mostly addressed using physical > +line and supplemented by GPIOs. This way you can hook up say a 8MiB flash > +to a 2MiB memory range and use the GPIOs to select a particular range. > + > + - compatible : "cfi-gpio-addr-flash" > + - reg : Address range of the mtd chip that is memory mapped, this is, > + on the previous example 2MiB. > + - bank-width : Width (in bytes) of the bank. Equal to the > + device width times the number of interleaved chips. > + - gpios: List of GPIO specifiers that will be used to address the MSBs address > + lines. The order goes from LSB to MSB. I'd recommend naming the GPIO set (addr-gpios or msb-addr-gpios?), just to make things clear. > + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip > + is going to be probed. If omitted, assumed to be equal to "cfi_probe". > + - #address-cells, #size-cells : Must be present if the device has > + sub-nodes representing partitions (see below). In this case > + both #address-cells and #size-cells must be equal to 1. > + > +The device tree may optionally contain sub-nodes describing partitions of the > +address space. Check partition.txt for more details. > + > +Example: > + > + flash@300000 { > + #address-cells = <1>; > + #size-cells = <1>; > + compatible = "cfi-gpio-addr-flash"; > + bank-width = <2>; > + reg = < 0x00300000 0x00200000 >; > + gpios = <&gpio_0 3 0>, <&gpio_0 4 0>; > + partitions { > + compatible = "fixed-partitions"; > + #address-cells = <1>; > + #size-cells = <1>; > + > + partition@0 { > + reg = < 0x0 0x200000 >; > + label = "Golden Bitstream"; > + }; > + partition@200000 { > + reg = < 0x200000 0x200000 >; > + label = "User Bitstream"; > + }; > + partition@400000 { > + reg = < 0x400000 0x200000 >; > + label = "V4L Controls"; > + }; > + partition@600000 { > + reg = < 0x600000 0x200000 >; > + label = "Production Data"; > + }; > + } > + } ;
On Wed, 3 Oct 2018 21:38:58 +0200 Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > Add documentation for gpio-addr-flash. This binding allow creating > flash devices that are paged using GPIOs. > > Cc: devicetree@vger.kernel.org > Reviewed-by: Rob Herring <robh@kernel.org> > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> > --- > .../bindings/mtd/gpio-addr-flash.txt | 54 +++++++++++++++++++ > 1 file changed, 54 insertions(+) > create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > new file mode 100644 > index 000000000000..5006a26e1753 > --- /dev/null > +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > @@ -0,0 +1,54 @@ > +Memory Mapped flash with some address lines addressed using GPIOs > + > +Handle the case where a flash device is mostly addressed using physical > +line and supplemented by GPIOs. This way you can hook up say a 8MiB flash > +to a 2MiB memory range and use the GPIOs to select a particular range. > + > + - compatible : "cfi-gpio-addr-flash" > + - reg : Address range of the mtd chip that is memory mapped, this is, > + on the previous example 2MiB. > + - bank-width : Width (in bytes) of the bank. Equal to the > + device width times the number of interleaved chips. > + - gpios: List of GPIO specifiers that will be used to address the MSBs address > + lines. The order goes from LSB to MSB. > + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip > + is going to be probed. If omitted, assumed to be equal to "cfi_probe". Looks like other bindings are encoding the probe type in the compatible [1][2], and we should probably follow what's been done by others. > + - #address-cells, #size-cells : Must be present if the device has > + sub-nodes representing partitions (see below). In this case > + both #address-cells and #size-cells must be equal to 1. > + > +The device tree may optionally contain sub-nodes describing partitions of the > +address space. Check partition.txt for more details. > + > +Example: > + > + flash@300000 { > + #address-cells = <1>; > + #size-cells = <1>; You should not have the #address-cells and #size-cells props defined at this level, it's done in the partitions node already. > + compatible = "cfi-gpio-addr-flash"; > + bank-width = <2>; > + reg = < 0x00300000 0x00200000 >; > + gpios = <&gpio_0 3 0>, <&gpio_0 4 0>; > + partitions { > + compatible = "fixed-partitions"; > + #address-cells = <1>; > + #size-cells = <1>; > + > + partition@0 { > + reg = < 0x0 0x200000 >; > + label = "Golden Bitstream"; > + }; > + partition@200000 { > + reg = < 0x200000 0x200000 >; > + label = "User Bitstream"; > + }; > + partition@400000 { > + reg = < 0x400000 0x200000 >; > + label = "V4L Controls"; > + }; > + partition@600000 { > + reg = < 0x600000 0x200000 >; > + label = "Production Data"; > + }; > + } > + } ; [1]https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/mtd/cortina,gemini-flash.txt [2]https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/mtd/arm-versatile.txt
Hi Boris On Wed, Oct 3, 2018 at 11:27 PM Boris Brezillon <boris.brezillon@bootlin.com> wrote: > > On Wed, 3 Oct 2018 21:38:58 +0200 > Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > > > Add documentation for gpio-addr-flash. This binding allow creating > > flash devices that are paged using GPIOs. > > > > Cc: devicetree@vger.kernel.org > > Reviewed-by: Rob Herring <robh@kernel.org> > > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> > > --- > > .../bindings/mtd/gpio-addr-flash.txt | 54 +++++++++++++++++++ > > 1 file changed, 54 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > new file mode 100644 > > index 000000000000..5006a26e1753 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > @@ -0,0 +1,54 @@ > > +Memory Mapped flash with some address lines addressed using GPIOs > > + > > +Handle the case where a flash device is mostly addressed using physical > > +line and supplemented by GPIOs. This way you can hook up say a 8MiB flash > > +to a 2MiB memory range and use the GPIOs to select a particular range. > > + > > + - compatible : "cfi-gpio-addr-flash" > > + - reg : Address range of the mtd chip that is memory mapped, this is, > > + on the previous example 2MiB. > > + - bank-width : Width (in bytes) of the bank. Equal to the > > + device width times the number of interleaved chips. > > + - gpios: List of GPIO specifiers that will be used to address the MSBs address > > + lines. The order goes from LSB to MSB. > > + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip > > + is going to be probed. If omitted, assumed to be equal to "cfi_probe". > > Looks like other bindings are encoding the probe type in the > compatible [1][2], and we should probably follow what's been done by > others. If I understood it right, they are special cases of physmap_of_core.c https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L242 The driver that handles the compatible is physmap_of_core.c, and afaik multiple drivers with the same compatible string is a very bad idea. We can convert the driver to something like Versatile or gemini, but then we will not support platform devices btw, the binding that I am used is used by: https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L91 Yes, I know is obsolete Tomorrow morning I will try to address your comments, test in hw and resend Thanks > > > + - #address-cells, #size-cells : Must be present if the device has > > + sub-nodes representing partitions (see below). In this case > > + both #address-cells and #size-cells must be equal to 1. > > + > > +The device tree may optionally contain sub-nodes describing partitions of the > > +address space. Check partition.txt for more details. > > + > > +Example: > > + > > + flash@300000 { > > + #address-cells = <1>; > > + #size-cells = <1>; > > You should not have the #address-cells and #size-cells props defined at > this level, it's done in the partitions node already. > > > + compatible = "cfi-gpio-addr-flash"; > > + bank-width = <2>; > > + reg = < 0x00300000 0x00200000 >; > > + gpios = <&gpio_0 3 0>, <&gpio_0 4 0>; > > + partitions { > > + compatible = "fixed-partitions"; > > + #address-cells = <1>; > > + #size-cells = <1>; > > + > > + partition@0 { > > + reg = < 0x0 0x200000 >; > > + label = "Golden Bitstream"; > > + }; > > + partition@200000 { > > + reg = < 0x200000 0x200000 >; > > + label = "User Bitstream"; > > + }; > > + partition@400000 { > > + reg = < 0x400000 0x200000 >; > > + label = "V4L Controls"; > > + }; > > + partition@600000 { > > + reg = < 0x600000 0x200000 >; > > + label = "Production Data"; > > + }; > > + } > > + } ; > > [1]https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/mtd/cortina,gemini-flash.txt > [2]https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/mtd/arm-versatile.txt
On Wed, 3 Oct 2018 23:53:27 +0200 Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > Hi Boris > On Wed, Oct 3, 2018 at 11:27 PM Boris Brezillon > <boris.brezillon@bootlin.com> wrote: > > > > On Wed, 3 Oct 2018 21:38:58 +0200 > > Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > > > > > Add documentation for gpio-addr-flash. This binding allow creating > > > flash devices that are paged using GPIOs. > > > > > > Cc: devicetree@vger.kernel.org > > > Reviewed-by: Rob Herring <robh@kernel.org> > > > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> > > > --- > > > .../bindings/mtd/gpio-addr-flash.txt | 54 +++++++++++++++++++ > > > 1 file changed, 54 insertions(+) > > > create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > > > diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > new file mode 100644 > > > index 000000000000..5006a26e1753 > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > @@ -0,0 +1,54 @@ > > > +Memory Mapped flash with some address lines addressed using GPIOs > > > + > > > +Handle the case where a flash device is mostly addressed using physical > > > +line and supplemented by GPIOs. This way you can hook up say a 8MiB flash > > > +to a 2MiB memory range and use the GPIOs to select a particular range. > > > + > > > + - compatible : "cfi-gpio-addr-flash" > > > + - reg : Address range of the mtd chip that is memory mapped, this is, > > > + on the previous example 2MiB. > > > + - bank-width : Width (in bytes) of the bank. Equal to the > > > + device width times the number of interleaved chips. > > > + - gpios: List of GPIO specifiers that will be used to address the MSBs address > > > + lines. The order goes from LSB to MSB. > > > + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip > > > + is going to be probed. If omitted, assumed to be equal to "cfi_probe". > > > > Looks like other bindings are encoding the probe type in the > > compatible [1][2], and we should probably follow what's been done by > > others. > > If I understood it right, they are special cases of physmap_of_core.c > https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L242 > > The driver that handles the compatible is physmap_of_core.c, and afaik > multiple drivers with the same > compatible string is a very bad idea. Yes, I know. > > We can convert the driver to something like Versatile or gemini, but > then we will not support platform devices > > btw, the binding that I am used is used by: > https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L91 Actually, the more I think about it the more I realize this should somehow be integrated to the physmap core logic. I mean, there's nothing controller/platform specific in what the gpio-physmap driver does. We could basically add the msb_addr_gpios related fields to map_info, let physmap.c and physmap_of_core.c call devm_gpiod_get_array_optional() and, based on the returned value, call simple_map_init() (when the pointer is NULL) or gpio_addr_map_init() (when the pointer is valid). gpio_addr_map_init() would still be implemented in gpio-addr-flash.c so that we can still enable/disable support for this feature (providing dummy wrappers when it's disabled). By doing that, we also keep a single driver which matches a generic compatible string. We also stay compatible with .c based board files.
On Thu, 4 Oct 2018 00:14:15 +0200 Boris Brezillon <boris.brezillon@bootlin.com> wrote: > On Wed, 3 Oct 2018 23:53:27 +0200 > Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > > > Hi Boris > > On Wed, Oct 3, 2018 at 11:27 PM Boris Brezillon > > <boris.brezillon@bootlin.com> wrote: > > > > > > On Wed, 3 Oct 2018 21:38:58 +0200 > > > Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > > > > > > > Add documentation for gpio-addr-flash. This binding allow creating > > > > flash devices that are paged using GPIOs. > > > > > > > > Cc: devicetree@vger.kernel.org > > > > Reviewed-by: Rob Herring <robh@kernel.org> > > > > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> > > > > --- > > > > .../bindings/mtd/gpio-addr-flash.txt | 54 +++++++++++++++++++ > > > > 1 file changed, 54 insertions(+) > > > > create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > > > > > diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > new file mode 100644 > > > > index 000000000000..5006a26e1753 > > > > --- /dev/null > > > > +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > @@ -0,0 +1,54 @@ > > > > +Memory Mapped flash with some address lines addressed using GPIOs > > > > + > > > > +Handle the case where a flash device is mostly addressed using physical > > > > +line and supplemented by GPIOs. This way you can hook up say a 8MiB flash > > > > +to a 2MiB memory range and use the GPIOs to select a particular range. > > > > + > > > > + - compatible : "cfi-gpio-addr-flash" > > > > + - reg : Address range of the mtd chip that is memory mapped, this is, > > > > + on the previous example 2MiB. > > > > + - bank-width : Width (in bytes) of the bank. Equal to the > > > > + device width times the number of interleaved chips. > > > > + - gpios: List of GPIO specifiers that will be used to address the MSBs address > > > > + lines. The order goes from LSB to MSB. > > > > + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip > > > > + is going to be probed. If omitted, assumed to be equal to "cfi_probe". > > > > > > Looks like other bindings are encoding the probe type in the > > > compatible [1][2], and we should probably follow what's been done by > > > others. > > > > If I understood it right, they are special cases of physmap_of_core.c > > https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L242 > > > > The driver that handles the compatible is physmap_of_core.c, and afaik > > multiple drivers with the same > > compatible string is a very bad idea. > > Yes, I know. > > > > > We can convert the driver to something like Versatile or gemini, but > > then we will not support platform devices > > > > btw, the binding that I am used is used by: > > https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L91 > > Actually, the more I think about it the more I realize this should > somehow be integrated to the physmap core logic. I mean, there's nothing > controller/platform specific in what the gpio-physmap driver does. > > We could basically add the msb_addr_gpios related fields to map_info, > let physmap.c and physmap_of_core.c call > devm_gpiod_get_array_optional() and, based on the returned value, > call simple_map_init() (when the pointer is NULL) or > gpio_addr_map_init() (when the pointer is valid). Or even better, let simple_map_init() call gpio_addr_map_init() when map->addr_gpios != NULL, so that you don't even have to duplicate the selection logic in physmap.c and physmap_of_core.c. > > gpio_addr_map_init() would still be implemented in gpio-addr-flash.c so > that we can still enable/disable support for this feature (providing > dummy wrappers when it's disabled). By doing that, we also keep a single > driver which matches a generic compatible string. We also stay > compatible with .c based board files.
HI Boris On Thu, Oct 4, 2018 at 12:19 AM Boris Brezillon <boris.brezillon@bootlin.com> wrote: > > On Thu, 4 Oct 2018 00:14:15 +0200 > Boris Brezillon <boris.brezillon@bootlin.com> wrote: > > > On Wed, 3 Oct 2018 23:53:27 +0200 > > Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > > > > > Hi Boris > > > On Wed, Oct 3, 2018 at 11:27 PM Boris Brezillon > > > <boris.brezillon@bootlin.com> wrote: > > > > > > > > On Wed, 3 Oct 2018 21:38:58 +0200 > > > > Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote: > > > > > > > > > Add documentation for gpio-addr-flash. This binding allow creating > > > > > flash devices that are paged using GPIOs. > > > > > > > > > > Cc: devicetree@vger.kernel.org > > > > > Reviewed-by: Rob Herring <robh@kernel.org> > > > > > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> > > > > > --- > > > > > .../bindings/mtd/gpio-addr-flash.txt | 54 +++++++++++++++++++ > > > > > 1 file changed, 54 insertions(+) > > > > > create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > > new file mode 100644 > > > > > index 000000000000..5006a26e1753 > > > > > --- /dev/null > > > > > +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > > @@ -0,0 +1,54 @@ > > > > > +Memory Mapped flash with some address lines addressed using GPIOs > > > > > + > > > > > +Handle the case where a flash device is mostly addressed using physical > > > > > +line and supplemented by GPIOs. This way you can hook up say a 8MiB flash > > > > > +to a 2MiB memory range and use the GPIOs to select a particular range. > > > > > + > > > > > + - compatible : "cfi-gpio-addr-flash" > > > > > + - reg : Address range of the mtd chip that is memory mapped, this is, > > > > > + on the previous example 2MiB. > > > > > + - bank-width : Width (in bytes) of the bank. Equal to the > > > > > + device width times the number of interleaved chips. > > > > > + - gpios: List of GPIO specifiers that will be used to address the MSBs address > > > > > + lines. The order goes from LSB to MSB. > > > > > + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip > > > > > + is going to be probed. If omitted, assumed to be equal to "cfi_probe". > > > > > > > > Looks like other bindings are encoding the probe type in the > > > > compatible [1][2], and we should probably follow what's been done by > > > > others. > > > > > > If I understood it right, they are special cases of physmap_of_core.c > > > https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L242 > > > > > > The driver that handles the compatible is physmap_of_core.c, and afaik > > > multiple drivers with the same > > > compatible string is a very bad idea. > > > > Yes, I know. > > > > > > > > We can convert the driver to something like Versatile or gemini, but > > > then we will not support platform devices > > > > > > btw, the binding that I am used is used by: > > > https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L91 > > > > Actually, the more I think about it the more I realize this should > > somehow be integrated to the physmap core logic. I mean, there's nothing > > controller/platform specific in what the gpio-physmap driver does. > > > > We could basically add the msb_addr_gpios related fields to map_info, > > let physmap.c and physmap_of_core.c call > > devm_gpiod_get_array_optional() and, based on the returned value, > > call simple_map_init() (when the pointer is NULL) or > > gpio_addr_map_init() (when the pointer is valid). > > Or even better, let simple_map_init() call gpio_addr_map_init() when > map->addr_gpios != NULL, so that you don't even have to duplicate the > selection logic in physmap.c and physmap_of_core.c. > I am all in for the removal of duplicated code. But I have implemented it slightly different, following gemini and versatile In physmap_of_core.c I have added err = of_flash_probe_gpio(dev, dp, &info->list[i].map); if (err){ iounmap(info->list[i].map.virt); goto err_out; } and on gpio-addr-flash the code for DT is simply int of_flash_probe_gpio(struct platform_device *pdev, struct device_node *np, struct map_info *map) { struct async_state *state; if (!of_device_is_compatible(np, "mtd,gpio-addr-flash")) return 0; state = devm_kzalloc(&pdev->dev, sizeof(*state), GFP_KERNEL); if (!state) return -ENOMEM; return gpio_flash_probe_common(&pdev->dev, state, map); } You can take a look to the code at https://github.com/ribalda/linux/tree/gpio-addr-flash-v6 once it is tested on hw I will commit to the list I think now we are getting into something quite good :) Thanks! > > > > gpio_addr_map_init() would still be implemented in gpio-addr-flash.c so > > that we can still enable/disable support for this feature (providing > > dummy wrappers when it's disabled). By doing that, we also keep a single > > driver which matches a generic compatible string. We also stay > > compatible with .c based board files. >
diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt new file mode 100644 index 000000000000..5006a26e1753 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt @@ -0,0 +1,54 @@ +Memory Mapped flash with some address lines addressed using GPIOs + +Handle the case where a flash device is mostly addressed using physical +line and supplemented by GPIOs. This way you can hook up say a 8MiB flash +to a 2MiB memory range and use the GPIOs to select a particular range. + + - compatible : "cfi-gpio-addr-flash" + - reg : Address range of the mtd chip that is memory mapped, this is, + on the previous example 2MiB. + - bank-width : Width (in bytes) of the bank. Equal to the + device width times the number of interleaved chips. + - gpios: List of GPIO specifiers that will be used to address the MSBs address + lines. The order goes from LSB to MSB. + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip + is going to be probed. If omitted, assumed to be equal to "cfi_probe". + - #address-cells, #size-cells : Must be present if the device has + sub-nodes representing partitions (see below). In this case + both #address-cells and #size-cells must be equal to 1. + +The device tree may optionally contain sub-nodes describing partitions of the +address space. Check partition.txt for more details. + +Example: + + flash@300000 { + #address-cells = <1>; + #size-cells = <1>; + compatible = "cfi-gpio-addr-flash"; + bank-width = <2>; + reg = < 0x00300000 0x00200000 >; + gpios = <&gpio_0 3 0>, <&gpio_0 4 0>; + partitions { + compatible = "fixed-partitions"; + #address-cells = <1>; + #size-cells = <1>; + + partition@0 { + reg = < 0x0 0x200000 >; + label = "Golden Bitstream"; + }; + partition@200000 { + reg = < 0x200000 0x200000 >; + label = "User Bitstream"; + }; + partition@400000 { + reg = < 0x400000 0x200000 >; + label = "V4L Controls"; + }; + partition@600000 { + reg = < 0x600000 0x200000 >; + label = "Production Data"; + }; + } + } ;