On Wed, 5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@xxxxxxxxx> 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@xxxxxxxxx>
> ---
> 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@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@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.
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