[PATCH v5 2/2] mfd: Add Samsung Exynos Low Power Audio Subsystem driver

From: Sylwester Nawrocki
Date: Tue Aug 09 2016 - 09:39:06 EST

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 <ideal.song@xxxxxxxxxxx>
Signed-off-by: Beomho Seo <beomho.seo@xxxxxxxxxxx>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
---

Changes since v4:
- none.

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 2d1fb64..a7ec890 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -281,6 +281,14 @@ 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 2ba3ba3..41510bb 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 <ideal.song@xxxxxxxxxxx>
+ * Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
+ *
+ * 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