memory: add a driver for atmel ram controllers

Atmel SoCs have one or multiple RAM controllers that need one or multiple clocks
to run.
This driver handle those clocks.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>

3 files changed, 109 insertions, 0 deletions

diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
index c59e9c96e86d..257061c3c816 100644
--- a/drivers/memory/Kconfig
+++ b/drivers/memory/Kconfig
@@ -7,6 +7,16 @@ menuconfig MEMORY
 
 if MEMORY
 
+config ATMEL_SDRAMC
+        bool "Atmel (Multi-port DDR-)SDRAM Controller"
+        default y
+        depends on ARCH_AT91 && OF
+        help
+          This driver is for Atmel SDRAM Controller or Atmel Multi-port
+          DDR-SDRAM Controller available on Atmel AT91SAM9 and SAMA5 SoCs.
+          Starting with the at91sam9g45, this controller supports SDR, DDR and
+          LP-DDR memories.
+
 config TI_AEMIF
         tristate "Texas Instruments AEMIF driver"
         depends on (ARCH_DAVINCI || ARCH_KEYSTONE) && OF
diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
index 71160a2b7313..b8637261e1a1 100644
--- a/drivers/memory/Makefile
+++ b/drivers/memory/Makefile
@@ -5,6 +5,7 @@
 ifeq ($(CONFIG_DDR),y)
 obj-$(CONFIG_OF)                += of_memory.o
 endif
+obj-$(CONFIG_ATMEL_SDRAMC)      += atmel-sdramc.o
 obj-$(CONFIG_TI_AEMIF)          += ti-aemif.o
 obj-$(CONFIG_TI_EMIF)           += emif.o
 obj-$(CONFIG_FSL_IFC)           += fsl_ifc.o
diff --git a/drivers/memory/atmel-sdramc.c b/drivers/memory/atmel-sdramc.c
new file mode 100644
index 000000000000..fed04e8efe75
--- /dev/null
+++ b/drivers/memory/atmel-sdramc.c
@@ -0,0 +1,98 @@
+/*
+ * Atmel (Multi-port DDR-)SDRAM Controller driver
+ *
+ * Copyright (C) 2014 Atmel
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+struct at91_ramc_caps {
+        bool has_ddrck;
+        bool has_mpddr_clk;
+};
+
+static const struct at91_ramc_caps at91rm9200_caps = { };
+
+static const struct at91_ramc_caps at91sam9g45_caps = {
+        .has_ddrck = 1,
+        .has_mpddr_clk = 0,
+};
+
+static const struct at91_ramc_caps sama5d3_caps = {
+        .has_ddrck = 1,
+        .has_mpddr_clk = 1,
+};
+
+static const struct of_device_id atmel_ramc_of_match[] = {
+        { .compatible = "atmel,at91rm9200-sdramc", .data = &at91rm9200_caps, },
+        { .compatible = "atmel,at91sam9260-sdramc", .data = &at91rm9200_caps, },
+        { .compatible = "atmel,at91sam9g45-ddramc", .data = &at91sam9g45_caps, },
+        { .compatible = "atmel,sama5d3-ddramc", .data = &sama5d3_caps, },
+        {},
+};
+MODULE_DEVICE_TABLE(of, atmel_ramc_of_match);
+
+static int atmel_ramc_probe(struct platform_device *pdev)
+{
+        const struct of_device_id *match;
+        const struct at91_ramc_caps *caps;
+        struct clk *clk;
+
+        match = of_match_device(atmel_ramc_of_match, &pdev->dev);
+        caps = match->data;
+
+        if (caps->has_ddrck) {
+                clk = devm_clk_get(&pdev->dev, "ddrck");
+                if (IS_ERR(clk))
+                        return PTR_ERR(clk);
+                clk_prepare_enable(clk);
+        }
+
+        if (caps->has_mpddr_clk) {
+                clk = devm_clk_get(&pdev->dev, "mpddr");
+                if (IS_ERR(clk)) {
+                        pr_err("AT91 RAMC: couldn't get mpddr clock\n");
+                        return PTR_ERR(clk);
+                }
+                clk_prepare_enable(clk);
+        }
+
+        return 0;
+}
+
+static struct platform_driver atmel_ramc_driver = {
+        .probe          = atmel_ramc_probe,
+        .driver         = {
+                .name   = "atmel-ramc",
+                .owner  = THIS_MODULE,
+                .of_match_table = atmel_ramc_of_match,
+        },
+};
+
+static int __init atmel_ramc_init(void)
+{
+        return platform_driver_register(&atmel_ramc_driver);
+}
+module_init(atmel_ramc_init);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
+MODULE_DESCRIPTION("Atmel (Multi-port DDR-)SDRAM Controller");