ARM: OMAP: gpmc: add DT bindings for GPMC timings and NAND

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>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
[tony@atomide.com: updated to apply]
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 173 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 1f0ec79aabf1..01ce462e265d 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"
 
@@ -1121,6 +1126,165 @@ int gpmc_calc_timings(struct gpmc_timings *gpmc_t,
         return 0;
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id gpmc_dt_ids[] = {
+        { .compatible = "ti,omap2420-gpmc" },
+        { .compatible = "ti,omap2430-gpmc" },
+        { .compatible = "ti,omap3430-gpmc" },   /* omap3430 & omap3630 */
+        { .compatible = "ti,omap4430-gpmc" },   /* omap4430 & omap4460 & omap543x */
+        { .compatible = "ti,am3352-gpmc" },     /* am335x devices */
+        { }
+};
+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 gpmc_probe(struct platform_device *pdev)
 {
         int rc;
@@ -1174,6 +1338,14 @@ static 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 +1363,7 @@ static struct platform_driver gpmc_driver = {
         .driver         = {
                 .name   = DEVICE_NAME,
                 .owner  = THIS_MODULE,
+                .of_match_table = of_match_ptr(gpmc_dt_ids),
         },
 };