mfd: Add JZ4740 ADC driver

This patch adds a MFD driver for the JZ4740 ADC unit. The driver is used to
demultiplex IRQs and synchronize access to shared registers between the
battery, hwmon and (future) touchscreen driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 393 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 8f5145b4b56..d59334f34bf 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -514,6 +514,14 @@ config MFD_JANZ_CMODIO
           host many different types of MODULbus daughterboards, including
           CAN and GPIO controllers.
 
+config MFD_JZ4740_ADC
+        tristate "Support for the JZ4740 SoC ADC core"
+        select MFD_CORE
+        depends on MACH_JZ4740
+        help
+          Say yes here if you want support for the ADC unit in the JZ4740 SoC.
+          This driver is necessary for jz4740-battery and jz4740-hwmon driver.
+
 endif # MFD_SUPPORT
 
 menu "Multimedia Capabilities Port drivers"
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 4410747f7b5..1f707796699 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -72,3 +72,4 @@ obj-$(CONFIG_PMIC_ADP5520)	+= adp5520.o
 obj-$(CONFIG_LPC_SCH)           += lpc_sch.o
 obj-$(CONFIG_MFD_RDC321X)       += rdc321x-southbridge.o
 obj-$(CONFIG_MFD_JANZ_CMODIO)   += janz-cmodio.o
+obj-$(CONFIG_MFD_JZ4740_ADC)    += jz4740-adc.o
diff --git a/drivers/mfd/jz4740-adc.c b/drivers/mfd/jz4740-adc.c
new file mode 100644
index 00000000000..7a844aef5dc
--- /dev/null
+++ b/drivers/mfd/jz4740-adc.c
@@ -0,0 +1,384 @@
+/*
+ * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
+ * JZ4740 SoC ADC driver
+ *
+ * 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;  either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * This driver synchronizes access to the JZ4740 ADC core between the
+ * JZ4740 battery and hwmon drivers.
+ */
+
+#include <linux/err.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <linux/clk.h>
+#include <linux/mfd/core.h>
+
+#include <linux/jz4740-adc.h>
+
+
+#define JZ_REG_ADC_ENABLE       0x00
+#define JZ_REG_ADC_CFG          0x04
+#define JZ_REG_ADC_CTRL         0x08
+#define JZ_REG_ADC_STATUS       0x0c
+
+#define JZ_REG_ADC_TOUCHSCREEN_BASE     0x10
+#define JZ_REG_ADC_BATTERY_BASE 0x1c
+#define JZ_REG_ADC_HWMON_BASE   0x20
+
+#define JZ_ADC_ENABLE_TOUCH     BIT(2)
+#define JZ_ADC_ENABLE_BATTERY   BIT(1)
+#define JZ_ADC_ENABLE_ADCIN     BIT(0)
+
+enum {
+        JZ_ADC_IRQ_ADCIN = 0,
+        JZ_ADC_IRQ_BATTERY,
+        JZ_ADC_IRQ_TOUCH,
+        JZ_ADC_IRQ_PENUP,
+        JZ_ADC_IRQ_PENDOWN,
+};
+
+struct jz4740_adc {
+        struct resource *mem;
+        void __iomem *base;
+
+        int irq;
+        int irq_base;
+
+        struct clk *clk;
+        atomic_t clk_ref;
+
+        spinlock_t lock;
+};
+
+static inline void jz4740_adc_irq_set_masked(struct jz4740_adc *adc, int irq,
+        bool masked)
+{
+        unsigned long flags;
+        uint8_t val;
+
+        irq -= adc->irq_base;
+
+        spin_lock_irqsave(&adc->lock, flags);
+
+        val = readb(adc->base + JZ_REG_ADC_CTRL);
+        if (masked)
+                val |= BIT(irq);
+        else
+                val &= ~BIT(irq);
+        writeb(val, adc->base + JZ_REG_ADC_CTRL);
+
+        spin_unlock_irqrestore(&adc->lock, flags);
+}
+
+static void jz4740_adc_irq_mask(unsigned int irq)
+{
+        struct jz4740_adc *adc = get_irq_chip_data(irq);
+        jz4740_adc_irq_set_masked(adc, irq, true);
+}
+
+static void jz4740_adc_irq_unmask(unsigned int irq)
+{
+        struct jz4740_adc *adc = get_irq_chip_data(irq);
+        jz4740_adc_irq_set_masked(adc, irq, false);
+}
+
+static void jz4740_adc_irq_ack(unsigned int irq)
+{
+        struct jz4740_adc *adc = get_irq_chip_data(irq);
+
+        irq -= adc->irq_base;
+        writeb(BIT(irq), adc->base + JZ_REG_ADC_STATUS);
+}
+
+static struct irq_chip jz4740_adc_irq_chip = {
+        .name = "jz4740-adc",
+        .mask = jz4740_adc_irq_mask,
+        .unmask = jz4740_adc_irq_unmask,
+        .ack = jz4740_adc_irq_ack,
+};
+
+static void jz4740_adc_irq_demux(unsigned int irq, struct irq_desc *desc)
+{
+        struct jz4740_adc *adc = get_irq_desc_data(desc);
+        uint8_t status;
+        unsigned int i;
+
+        status = readb(adc->base + JZ_REG_ADC_STATUS);
+
+        for (i = 0; i < 5; ++i) {
+                if (status & BIT(i))
+                        generic_handle_irq(adc->irq_base + i);
+        }
+}
+
+
+/* Refcounting for the ADC clock is done in here instead of in the clock
+ * framework, because it is the only clock which is shared between multiple
+ * devices and thus is the only clock which needs refcounting */
+static inline void jz4740_adc_clk_enable(struct jz4740_adc *adc)
+{
+        if (atomic_inc_return(&adc->clk_ref) == 1)
+                clk_enable(adc->clk);
+}
+
+static inline void jz4740_adc_clk_disable(struct jz4740_adc *adc)
+{
+        if (atomic_dec_return(&adc->clk_ref) == 0)
+                clk_disable(adc->clk);
+}
+
+static inline void jz4740_adc_set_enabled(struct jz4740_adc *adc, int engine,
+        bool enabled)
+{
+        unsigned long flags;
+        uint8_t val;
+
+        spin_lock_irqsave(&adc->lock, flags);
+
+        val = readb(adc->base + JZ_REG_ADC_ENABLE);
+        if (enabled)
+                val |= BIT(engine);
+        else
+                val &= BIT(engine);
+        writeb(val, adc->base + JZ_REG_ADC_ENABLE);
+
+        spin_unlock_irqrestore(&adc->lock, flags);
+}
+
+static int jz4740_adc_cell_enable(struct platform_device *pdev)
+{
+        struct jz4740_adc *adc = dev_get_drvdata(pdev->dev.parent);
+
+        jz4740_adc_clk_enable(adc);
+        jz4740_adc_set_enabled(adc, pdev->id, true);
+
+        return 0;
+}
+
+static int jz4740_adc_cell_disable(struct platform_device *pdev)
+{
+        struct jz4740_adc *adc = dev_get_drvdata(pdev->dev.parent);
+
+        jz4740_adc_set_enabled(adc, pdev->id, false);
+        jz4740_adc_clk_disable(adc);
+
+        return 0;
+}
+
+int jz4740_adc_set_config(struct device *dev, uint32_t mask, uint32_t val)
+{
+        struct jz4740_adc *adc = dev_get_drvdata(dev);
+        unsigned long flags;
+        uint32_t cfg;
+
+        if (!adc)
+                return -ENODEV;
+
+        spin_lock_irqsave(&adc->lock, flags);
+
+        cfg = readl(adc->base + JZ_REG_ADC_CFG);
+
+        cfg &= ~mask;
+        cfg |= val;
+
+        writel(cfg, adc->base + JZ_REG_ADC_CFG);
+
+        spin_unlock_irqrestore(&adc->lock, flags);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(jz4740_adc_set_config);
+
+static struct resource jz4740_hwmon_resources[] = {
+        {
+                .start = JZ_ADC_IRQ_ADCIN,
+                .flags = IORESOURCE_IRQ,
+        },
+        {
+                .start  = JZ_REG_ADC_HWMON_BASE,
+                .end    = JZ_REG_ADC_HWMON_BASE + 3,
+                .flags  = IORESOURCE_MEM,
+        },
+};
+
+static struct resource jz4740_battery_resources[] = {
+        {
+                .start = JZ_ADC_IRQ_BATTERY,
+                .flags = IORESOURCE_IRQ,
+        },
+        {
+                .start  = JZ_REG_ADC_BATTERY_BASE,
+                .end    = JZ_REG_ADC_BATTERY_BASE + 3,
+                .flags  = IORESOURCE_MEM,
+        },
+};
+
+const struct mfd_cell jz4740_adc_cells[] = {
+        {
+                .id = 0,
+                .name = "jz4740-hwmon",
+                .num_resources = ARRAY_SIZE(jz4740_hwmon_resources),
+                .resources = jz4740_hwmon_resources,
+                .platform_data = (void *)&jz4740_adc_cells[0],
+                .data_size = sizeof(struct mfd_cell),
+
+                .enable = jz4740_adc_cell_enable,
+                .disable = jz4740_adc_cell_disable,
+        },
+        {
+                .id = 1,
+                .name = "jz4740-battery",
+                .num_resources = ARRAY_SIZE(jz4740_battery_resources),
+                .resources = jz4740_battery_resources,
+                .platform_data = (void *)&jz4740_adc_cells[1],
+                .data_size = sizeof(struct mfd_cell),
+
+                .enable = jz4740_adc_cell_enable,
+                .disable = jz4740_adc_cell_disable,
+        },
+};
+
+static int __devinit jz4740_adc_probe(struct platform_device *pdev)
+{
+        int ret;
+        struct jz4740_adc *adc;
+        struct resource *mem_base;
+        int irq;
+
+        adc = kmalloc(sizeof(*adc), GFP_KERNEL);
+
+        adc->irq = platform_get_irq(pdev, 0);
+        if (adc->irq < 0) {
+                ret = adc->irq;
+                dev_err(&pdev->dev, "Failed to get platform irq: %d\n", ret);
+                goto err_free;
+        }
+
+        adc->irq_base = platform_get_irq(pdev, 1);
+        if (adc->irq_base < 0) {
+                ret = adc->irq_base;
+                dev_err(&pdev->dev, "Failed to get irq base: %d\n", ret);
+                goto err_free;
+        }
+
+        mem_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!mem_base) {
+                ret = -ENOENT;
+                dev_err(&pdev->dev, "Failed to get platform mmio resource\n");
+                goto err_free;
+        }
+
+        /* Only request the shared registers for the MFD driver */
+        adc->mem = request_mem_region(mem_base->start, JZ_REG_ADC_STATUS,
+                                        pdev->name);
+        if (!adc->mem) {
+                ret = -EBUSY;
+                dev_err(&pdev->dev, "Failed to request mmio memory region\n");
+                goto err_free;
+        }
+
+        adc->base = ioremap_nocache(adc->mem->start, resource_size(adc->mem));
+        if (!adc->base) {
+                ret = -EBUSY;
+                dev_err(&pdev->dev, "Failed to ioremap mmio memory\n");
+                goto err_release_mem_region;
+        }
+
+        adc->clk = clk_get(&pdev->dev, "adc");
+        if (IS_ERR(adc->clk)) {
+                ret = PTR_ERR(adc->clk);
+                dev_err(&pdev->dev, "Failed to get clock: %d\n", ret);
+                goto err_iounmap;
+        }
+
+        spin_lock_init(&adc->lock);
+        atomic_set(&adc->clk_ref, 0);
+
+        platform_set_drvdata(pdev, adc);
+
+        for (irq = adc->irq_base; irq < adc->irq_base + 5; ++irq) {
+                set_irq_chip_data(irq, adc);
+                set_irq_chip_and_handler(irq, &jz4740_adc_irq_chip,
+                    handle_level_irq);
+        }
+
+        set_irq_data(adc->irq, adc);
+        set_irq_chained_handler(adc->irq, jz4740_adc_irq_demux);
+
+        writeb(0x00, adc->base + JZ_REG_ADC_ENABLE);
+        writeb(0xff, adc->base + JZ_REG_ADC_CTRL);
+
+        return mfd_add_devices(&pdev->dev, 0, jz4740_adc_cells,
+                ARRAY_SIZE(jz4740_adc_cells), mem_base, adc->irq_base);
+
+err_iounmap:
+        platform_set_drvdata(pdev, NULL);
+        iounmap(adc->base);
+err_release_mem_region:
+        release_mem_region(adc->mem->start, resource_size(adc->mem));
+err_free:
+        kfree(adc);
+
+        return ret;
+}
+
+static int __devexit jz4740_adc_remove(struct platform_device *pdev)
+{
+        struct jz4740_adc *adc = platform_get_drvdata(pdev);
+
+        mfd_remove_devices(&pdev->dev);
+
+        set_irq_data(adc->irq, NULL);
+        set_irq_chained_handler(adc->irq, NULL);
+
+        iounmap(adc->base);
+        release_mem_region(adc->mem->start, resource_size(adc->mem));
+
+        clk_put(adc->clk);
+
+        platform_set_drvdata(pdev, NULL);
+
+        kfree(adc);
+
+        return 0;
+}
+
+struct platform_driver jz4740_adc_driver = {
+        .probe  = jz4740_adc_probe,
+        .remove = __devexit_p(jz4740_adc_remove),
+        .driver = {
+                .name = "jz4740-adc",
+                .owner = THIS_MODULE,
+        },
+};
+
+static int __init jz4740_adc_init(void)
+{
+        return platform_driver_register(&jz4740_adc_driver);
+}
+module_init(jz4740_adc_init);
+
+static void __exit jz4740_adc_exit(void)
+{
+        platform_driver_unregister(&jz4740_adc_driver);
+}
+module_exit(jz4740_adc_exit);
+
+MODULE_DESCRIPTION("JZ4740 SoC ADC driver");
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:jz4740-adc");