mfd: Add support for the MediaTek MT6397 PMIC

This adds support for the MediaTek MT6397 PMIC. This is a
multifunction device with the following sub modules:

- Regulator
- RTC
- Audio codec
- GPIO
- Clock

It is interfaced to the host controller using SPI interface by a proprietary
hardware called PMIC wrapper or pwrap. MT6397 MFD is a child device of the
pwrap.

Signed-off-by: Flora Fu, MediaTek
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

3 files changed, 238 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b5fb03c109bc..c602f7440e00 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -503,6 +503,16 @@ config MFD_MAX8998
           additional drivers must be enabled in order to use the functionality
           of the device.
 
+config MFD_MT6397
+        tristate "MediaTek MT6397 PMIC Support"
+        select MFD_CORE
+        select IRQ_DOMAIN
+        help
+          Say yes here to add support for MediaTek MT6397 PMIC. This is
+          a Power Management IC. This driver provides common support for
+          accessing the device; additional drivers must be enabled in order
+          to use the functionality of the device.
+
 config MFD_MENF21BMC
         tristate "MEN 14F021P00 Board Management Controller Support"
         depends on I2C
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index c8bb34929903..26303f712afb 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -181,3 +181,4 @@ obj-$(CONFIG_MFD_RT5033)	+= rt5033.o
 
 intel-soc-pmic-objs             := intel_soc_pmic_core.o intel_soc_pmic_crc.o
 obj-$(CONFIG_INTEL_SOC_PMIC)    += intel-soc-pmic.o
+obj-$(CONFIG_MFD_MT6397)        += mt6397-core.o
diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
new file mode 100644
index 000000000000..09bc7804952a
--- /dev/null
+++ b/drivers/mfd/mt6397-core.c
@@ -0,0 +1,227 @@
+/*
+ * Copyright (c) 2014 MediaTek Inc.
+ * Author: Flora Fu, MediaTek
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/regmap.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/mt6397/core.h>
+#include <linux/mfd/mt6397/registers.h>
+
+static const struct mfd_cell mt6397_devs[] = {
+        {
+                .name = "mt6397-rtc",
+                .of_compatible = "mediatek,mt6397-rtc",
+        }, {
+                .name = "mt6397-regulator",
+                .of_compatible = "mediatek,mt6397-regulator",
+        }, {
+                .name = "mt6397-codec",
+                .of_compatible = "mediatek,mt6397-codec",
+        }, {
+                .name = "mt6397-clk",
+                .of_compatible = "mediatek,mt6397-clk",
+        },
+};
+
+static void mt6397_irq_lock(struct irq_data *data)
+{
+        struct mt6397_chip *mt6397 = irq_get_chip_data(data->irq);
+
+        mutex_lock(&mt6397->irqlock);
+}
+
+static void mt6397_irq_sync_unlock(struct irq_data *data)
+{
+        struct mt6397_chip *mt6397 = irq_get_chip_data(data->irq);
+
+        regmap_write(mt6397->regmap, MT6397_INT_CON0, mt6397->irq_masks_cur[0]);
+        regmap_write(mt6397->regmap, MT6397_INT_CON1, mt6397->irq_masks_cur[1]);
+
+        mutex_unlock(&mt6397->irqlock);
+}
+
+static void mt6397_irq_disable(struct irq_data *data)
+{
+        struct mt6397_chip *mt6397 = irq_get_chip_data(data->irq);
+        int shift = data->hwirq & 0xf;
+        int reg = data->hwirq >> 4;
+
+        mt6397->irq_masks_cur[reg] &= ~BIT(shift);
+}
+
+static void mt6397_irq_enable(struct irq_data *data)
+{
+        struct mt6397_chip *mt6397 = irq_get_chip_data(data->irq);
+        int shift = data->hwirq & 0xf;
+        int reg = data->hwirq >> 4;
+
+        mt6397->irq_masks_cur[reg] |= BIT(shift);
+}
+
+static struct irq_chip mt6397_irq_chip = {
+        .name = "mt6397-irq",
+        .irq_bus_lock = mt6397_irq_lock,
+        .irq_bus_sync_unlock = mt6397_irq_sync_unlock,
+        .irq_enable = mt6397_irq_enable,
+        .irq_disable = mt6397_irq_disable,
+};
+
+static void mt6397_irq_handle_reg(struct mt6397_chip *mt6397, int reg,
+                int irqbase)
+{
+        unsigned int status;
+        int i, irq, ret;
+
+        ret = regmap_read(mt6397->regmap, reg, &status);
+        if (ret) {
+                dev_err(mt6397->dev, "Failed to read irq status: %d\n", ret);
+                return;
+        }
+
+        for (i = 0; i < 16; i++) {
+                if (status & BIT(i)) {
+                        irq = irq_find_mapping(mt6397->irq_domain, irqbase + i);
+                        if (irq)
+                                handle_nested_irq(irq);
+                }
+        }
+
+        regmap_write(mt6397->regmap, reg, status);
+}
+
+static irqreturn_t mt6397_irq_thread(int irq, void *data)
+{
+        struct mt6397_chip *mt6397 = data;
+
+        mt6397_irq_handle_reg(mt6397, MT6397_INT_STATUS0, 0);
+        mt6397_irq_handle_reg(mt6397, MT6397_INT_STATUS1, 16);
+
+        return IRQ_HANDLED;
+}
+
+static int mt6397_irq_domain_map(struct irq_domain *d, unsigned int irq,
+                                        irq_hw_number_t hw)
+{
+        struct mt6397_chip *mt6397 = d->host_data;
+
+        irq_set_chip_data(irq, mt6397);
+        irq_set_chip_and_handler(irq, &mt6397_irq_chip, handle_level_irq);
+        irq_set_nested_thread(irq, 1);
+#ifdef CONFIG_ARM
+        set_irq_flags(irq, IRQF_VALID);
+#else
+        irq_set_noprobe(irq);
+#endif
+
+        return 0;
+}
+
+static struct irq_domain_ops mt6397_irq_domain_ops = {
+        .map = mt6397_irq_domain_map,
+};
+
+static int mt6397_irq_init(struct mt6397_chip *mt6397)
+{
+        int ret;
+
+        mutex_init(&mt6397->irqlock);
+
+        /* Mask all interrupt sources */
+        regmap_write(mt6397->regmap, MT6397_INT_CON0, 0x0);
+        regmap_write(mt6397->regmap, MT6397_INT_CON1, 0x0);
+
+        mt6397->irq_domain = irq_domain_add_linear(mt6397->dev->of_node,
+                MT6397_IRQ_NR, &mt6397_irq_domain_ops, mt6397);
+        if (!mt6397->irq_domain) {
+                dev_err(mt6397->dev, "could not create irq domain\n");
+                return -ENOMEM;
+        }
+
+        ret = devm_request_threaded_irq(mt6397->dev, mt6397->irq, NULL,
+                mt6397_irq_thread, IRQF_ONESHOT, "mt6397-pmic", mt6397);
+        if (ret) {
+                dev_err(mt6397->dev, "failed to register irq=%d; err: %d\n",
+                        mt6397->irq, ret);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int mt6397_probe(struct platform_device *pdev)
+{
+        int ret;
+        struct mt6397_chip *mt6397;
+
+        mt6397 = devm_kzalloc(&pdev->dev, sizeof(*mt6397), GFP_KERNEL);
+        if (!mt6397)
+                return -ENOMEM;
+
+        mt6397->dev = &pdev->dev;
+        /*
+         * mt6397 MFD is child device of soc pmic wrapper.
+         * Regmap is set from its parent.
+         */
+        mt6397->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+        if (!mt6397->regmap)
+                return -ENODEV;
+
+        platform_set_drvdata(pdev, mt6397);
+
+        mt6397->irq = platform_get_irq(pdev, 0);
+        if (mt6397->irq > 0) {
+                ret = mt6397_irq_init(mt6397);
+                if (ret)
+                        return ret;
+        }
+
+        ret = mfd_add_devices(&pdev->dev, -1, mt6397_devs,
+                        ARRAY_SIZE(mt6397_devs), NULL, 0, NULL);
+        if (ret)
+                dev_err(&pdev->dev, "failed to add child devices: %d\n", ret);
+
+        return ret;
+}
+
+static int mt6397_remove(struct platform_device *pdev)
+{
+        mfd_remove_devices(&pdev->dev);
+
+        return 0;
+}
+
+static const struct of_device_id mt6397_of_match[] = {
+        { .compatible = "mediatek,mt6397" },
+        { }
+};
+MODULE_DEVICE_TABLE(of, mt6397_of_match);
+
+static struct platform_driver mt6397_driver = {
+        .probe = mt6397_probe,
+        .remove = mt6397_remove,
+        .driver = {
+                .name = "mt6397",
+                .of_match_table = of_match_ptr(mt6397_of_match),
+        },
+};
+
+module_platform_driver(mt6397_driver);
+
+MODULE_AUTHOR("Flora Fu, MediaTek");
+MODULE_DESCRIPTION("Driver for MediaTek MT6397 PMIC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:mt6397");