This patch adds common driver for the Top block of the Samsung Exynos
SoC Low Power Audio Subsystem. This is a minimal driver which prepares
resources for IP blocks like I2S, audio DMA and UART and exposes a regmap
for the Top block registers. Also system power ops are added to ensure
the Audio Subsystem is operational after system suspend/resume cycle.

Signed-off-by: Inha Song <[email protected]>
Signed-off-by: Beomho Seo <[email protected]>
Signed-off-by: Sylwester Nawrocki <[email protected]>
---

Changes since v3:
 - moved from sound/soc/samsung and rewritten as a MFD driver,
 - PMU register definitions moved to include/linux/mfd/syscon/exynos5-pmu.h,
 - added regmap for LPASS Top SFR region,
 - cleaned up register bit field defintions.

Changes since v2:
 - move misplaced SND_SAMSUNG_AUDSS Kconfig symbol addition
   to this patch.
---
 drivers/mfd/Kconfig                    |   8 ++
 drivers/mfd/Makefile                   |   1 +
 drivers/mfd/exynos-lpass.c             | 185 +++++++++++++++++++++++++++++++++
 include/linux/mfd/syscon/exynos5-pmu.h |   4 +-
 4 files changed, 197 insertions(+), 1 deletion(-)
 create mode 100644 drivers/mfd/exynos-lpass.c

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 1bcf601..fc2dffb 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -270,6 +270,14 @@ config MFD_DLN2
          etc. must be enabled in order to use the functionality of
          the device.

+config MFD_EXYNOS_LPASS
+       tristate "Samsung Exynos SoC Low Power Audio Subsystem"
+       select MFD_CORE
+       select REGMAP_MMIO
+       help
+         Select this option to enable support for Samsung Exynos Low Power
+         Audio Subsystem.
+
 config MFD_MC13XXX
        tristate
        depends on (SPI_MASTER || I2C)
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 42a66e1..5c4be31 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_MFD_BCM590XX)    += bcm590xx.o
 obj-$(CONFIG_MFD_CROS_EC)      += cros_ec.o
 obj-$(CONFIG_MFD_CROS_EC_I2C)  += cros_ec_i2c.o
 obj-$(CONFIG_MFD_CROS_EC_SPI)  += cros_ec_spi.o
+obj-$(CONFIG_MFD_EXYNOS_LPASS) += exynos-lpass.o

 rtsx_pci-objs                  := rtsx_pcr.o rts5209.o rts5229.o rtl8411.o 
rts5227.o rts5249.o
 obj-$(CONFIG_MFD_RTSX_PCI)     += rtsx_pci.o
diff --git a/drivers/mfd/exynos-lpass.c b/drivers/mfd/exynos-lpass.c
new file mode 100644
index 0000000..956ce1f
--- /dev/null
+++ b/drivers/mfd/exynos-lpass.c
@@ -0,0 +1,185 @@
+/*
+ * Copyright (C) 2015 - 2016 Samsung Electronics Co., Ltd.
+ *
+ * Authors: Inha Song <[email protected]>
+ *          Sylwester Nawrocki <[email protected]>
+ *
+ * Samsung Exynos SoC series Low Power Audio Subsystem driver.
+ *
+ * This module provides regmap for the Top SFR region and instantiates
+ * devices for IP blocks like DMAC, I2S, UART.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/exynos5-pmu.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+/* LPASS Top register definitions */
+#define SFR_LPASS_CORE_SW_RESET                (0x08)
+#define  LPASS_SB_SW_RESET             (1 << 11)
+#define  LPASS_UART_SW_RESET           (1 << 10)
+#define  LPASS_PCM_SW_RESET            (1 << 9)
+#define  LPASS_I2S_SW_RESET            (1 << 8)
+#define  LPASS_WDT1_SW_RESET           (1 << 4)
+#define  LPASS_WDT0_SW_RESET           (1 << 3)
+#define  LPASS_TIMER_SW_RESET          (1 << 2)
+#define  LPASS_MEM_SW_RESET            (1 << 1)
+#define  LPASS_DMA_SW_RESET            (1 << 0)
+
+#define SFR_LPASS_INTR_CA5_MASK                (0x48)
+#define SFR_LPASS_INTR_CPU_MASK                (0x58)
+#define  LPASS_INTR_APM                        (1 << 9)
+#define  LPASS_INTR_MIF                        (1 << 8)
+#define  LPASS_INTR_TIMER              (1 << 7)
+#define  LPASS_INTR_DMA                        (1 << 6)
+#define  LPASS_INTR_GPIO               (1 << 5)
+#define  LPASS_INTR_I2S                        (1 << 4)
+#define  LPASS_INTR_PCM                        (1 << 3)
+#define  LPASS_INTR_SLIMBUS            (1 << 2)
+#define  LPASS_INTR_UART               (1 << 1)
+#define  LPASS_INTR_SFR                        (1 << 0)
+
+struct exynos_lpass {
+       struct regmap *pmu;
+       struct regmap *top;
+};
+
+static void exynos_lpass_core_sw_reset(struct exynos_lpass *lpass, int mask)
+{
+       unsigned int val = 0;
+
+       regmap_read(lpass->top, SFR_LPASS_CORE_SW_RESET, &val);
+
+       val &= ~mask;
+       regmap_write(lpass->top, SFR_LPASS_CORE_SW_RESET, val);
+
+       usleep_range(100, 150);
+
+       val |= mask;
+       regmap_write(lpass->top, SFR_LPASS_CORE_SW_RESET, val);
+}
+
+static void exynos_lpass_enable(struct exynos_lpass *lpass)
+{
+       /* Unmask SFR, DMA and I2S interrupt */
+       regmap_write(lpass->top, SFR_LPASS_INTR_CA5_MASK,
+                    LPASS_INTR_SFR | LPASS_INTR_DMA | LPASS_INTR_I2S);
+
+       regmap_write(lpass->top, SFR_LPASS_INTR_CPU_MASK,
+                    LPASS_INTR_SFR | LPASS_INTR_DMA | LPASS_INTR_I2S);
+
+       /* Activate related PADs from retention state */
+       regmap_write(lpass->pmu, EXYNOS5433_PAD_RETENTION_AUD_OPTION,
+                    EXYNOS5433_PAD_INITIATE_WAKEUP_FROM_LOWPWR);
+
+       exynos_lpass_core_sw_reset(lpass, LPASS_I2S_SW_RESET);
+       exynos_lpass_core_sw_reset(lpass, LPASS_DMA_SW_RESET);
+       exynos_lpass_core_sw_reset(lpass, LPASS_MEM_SW_RESET);
+}
+
+static void exynos_lpass_disable(struct exynos_lpass *lpass)
+{
+       /* Mask any unmasked IP interrupt sources */
+       regmap_write(lpass->top, SFR_LPASS_INTR_CPU_MASK, 0);
+       regmap_write(lpass->top, SFR_LPASS_INTR_CA5_MASK, 0);
+
+       /* Deactivate related PADs from retention state */
+       regmap_write(lpass->pmu, EXYNOS5433_PAD_RETENTION_AUD_OPTION, 0);
+}
+
+static const struct regmap_config exynos_lpass_reg_conf = {
+       .reg_bits       = 32,
+       .reg_stride     = 4,
+       .val_bits       = 32,
+       .max_register   = 0xfc,
+       .fast_io        = true,
+};
+
+static int exynos_lpass_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct exynos_lpass *lpass;
+       void __iomem *base_top;
+       struct resource *res;
+
+       if (!dev->of_node)
+               return -ENODEV;
+
+       lpass = devm_kzalloc(dev, sizeof(*lpass), GFP_KERNEL);
+       if (!lpass)
+               return -ENOMEM;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+       base_top = devm_ioremap_resource(dev, res);
+       if (IS_ERR(base_top))
+               return PTR_ERR(base_top);
+
+       lpass->top = regmap_init_mmio(dev, base_top,
+                                       &exynos_lpass_reg_conf);
+       if (IS_ERR(lpass->top)) {
+               dev_err(dev, "LPASS top regmap initialization failed\n");
+               return PTR_ERR(lpass->top);
+       }
+
+       lpass->pmu = syscon_regmap_lookup_by_phandle(dev->of_node,
+                                               "samsung,pmu-syscon");
+       if (IS_ERR(lpass->pmu)) {
+               dev_err(dev, "Failed to lookup PMU regmap\n");
+               return PTR_ERR(lpass->pmu);
+       }
+
+       platform_set_drvdata(pdev, lpass);
+       exynos_lpass_enable(lpass);
+
+       return of_platform_populate(dev->of_node, NULL, NULL, dev);
+}
+
+static int exynos_lpass_suspend(struct device *dev)
+{
+       struct exynos_lpass *lpass = dev_get_drvdata(dev);
+
+       exynos_lpass_disable(lpass);
+       return 0;
+}
+
+static int exynos_lpass_resume(struct device *dev)
+{
+       struct exynos_lpass *lpass = dev_get_drvdata(dev);
+
+       exynos_lpass_enable(lpass);
+       return 0;
+}
+
+static const struct of_device_id exynos_lpass_of_match[] = {
+       { .compatible   = "samsung,exynos5433-lpass" },
+       { },
+};
+MODULE_DEVICE_TABLE(of, exynos_lpass_of_match);
+
+static SIMPLE_DEV_PM_OPS(lpass_pm_ops, exynos_lpass_suspend,
+                                       exynos_lpass_resume);
+
+static struct platform_driver exynos_lpass_driver = {
+       .driver = {
+               .name           = "exynos-lpass",
+               .pm             = &lpass_pm_ops,
+               .of_match_table = exynos_lpass_of_match,
+       },
+       .probe  = exynos_lpass_probe,
+};
+module_platform_driver(exynos_lpass_driver);
+
+MODULE_DESCRIPTION("Samsung Low Power Audio Subsystem driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/syscon/exynos5-pmu.h 
b/include/linux/mfd/syscon/exynos5-pmu.h
index 76f30f9..c28ff21 100644
--- a/include/linux/mfd/syscon/exynos5-pmu.h
+++ b/include/linux/mfd/syscon/exynos5-pmu.h
@@ -43,8 +43,10 @@
 #define EXYNOS5433_MIPI_PHY2_CONTROL           (0x718)

 #define EXYNOS5_PHY_ENABLE                     BIT(0)
-
 #define EXYNOS5_MIPI_PHY_S_RESETN              BIT(1)
 #define EXYNOS5_MIPI_PHY_M_RESETN              BIT(2)

+#define EXYNOS5433_PAD_RETENTION_AUD_OPTION            (0x3028)
+#define EXYNOS5433_PAD_INITIATE_WAKEUP_FROM_LOWPWR     BIT(28)
+
 #endif /* _LINUX_MFD_SYSCON_PMU_EXYNOS5_H_ */
--
1.9.1

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