Support BD71837 gateable 32768 Hz clock.

Signed-off-by: Matti Vaittinen <matti.vaitti...@fi.rohmeurope.com>
---
 drivers/clk/Kconfig       |   9 +++
 drivers/clk/Makefile      |   1 +
 drivers/clk/clk-bd71837.c | 154 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 drivers/clk/clk-bd71837.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 41492e980ef4..4b045699bb5e 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -279,6 +279,15 @@ config COMMON_CLK_STM32H7
        ---help---
          Support for stm32h7 SoC family clocks
 
+config COMMON_CLK_BD71837
+       tristate "Clock driver for ROHM BD71837 PMIC MFD"
+       depends on MFD_BD71837
+       depends on I2C=y
+       depends on OF
+       help
+         This driver supports ROHM BD71837 PMIC clock.
+
+
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
 source "drivers/clk/imgtec/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index de6d06ac790b..8393c4af7d5a 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -21,6 +21,7 @@ endif
 obj-$(CONFIG_MACH_ASM9260)             += clk-asm9260.o
 obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)    += clk-axi-clkgen.o
 obj-$(CONFIG_ARCH_AXXIA)               += clk-axm5516.o
+obj-$(CONFIG_COMMON_CLK_BD71837)       += clk-bd71837.o
 obj-$(CONFIG_COMMON_CLK_CDCE706)       += clk-cdce706.o
 obj-$(CONFIG_COMMON_CLK_CDCE925)       += clk-cdce925.o
 obj-$(CONFIG_ARCH_CLPS711X)            += clk-clps711x.o
diff --git a/drivers/clk/clk-bd71837.c b/drivers/clk/clk-bd71837.c
new file mode 100644
index 000000000000..632b8c28c9e2
--- /dev/null
+++ b/drivers/clk/clk-bd71837.c
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2018 ROHM Semiconductors */
+/*
+ * bd71837.c  --  ROHM BD71837MWV clock driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mfd/bd71837.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+
+static int bd71837_clk_enable(struct clk_hw *hw);
+static void bd71837_clk_disable(struct clk_hw *hw);
+static int bd71837_clk_is_enabled(struct clk_hw *hw);
+
+struct bd71837_clk {
+       struct clk_hw hw;
+       uint8_t reg;
+       uint8_t mask;
+       unsigned long rate;
+       struct platform_device *pdev;
+       struct bd71837 *mfd;
+};
+
+static unsigned long bd71837_clk_recalc_rate(struct clk_hw *hw,
+                                            unsigned long parent_rate);
+
+static const struct clk_ops bd71837_clk_ops = {
+       .recalc_rate = &bd71837_clk_recalc_rate,
+       .prepare = &bd71837_clk_enable,
+       .unprepare = &bd71837_clk_disable,
+       .is_prepared = &bd71837_clk_is_enabled,
+};
+
+static int bd71837_clk_set(struct clk_hw *hw, int status)
+{
+       struct bd71837_clk *c = container_of(hw, struct bd71837_clk, hw);
+
+       return bd71837_update_bits(c->mfd, c->reg, c->mask, status);
+}
+
+static void bd71837_clk_disable(struct clk_hw *hw)
+{
+       int rv;
+       struct bd71837_clk *c = container_of(hw, struct bd71837_clk, hw);
+
+       rv = bd71837_clk_set(hw, 0);
+       if (rv)
+               dev_err(&c->pdev->dev, "Failed to disable 32K clk (%d)\n", rv);
+}
+
+static int bd71837_clk_enable(struct clk_hw *hw)
+{
+       return bd71837_clk_set(hw, 1);
+}
+
+static int bd71837_clk_is_enabled(struct clk_hw *hw)
+{
+       struct bd71837_clk *c = container_of(hw, struct bd71837_clk, hw);
+
+       return c->mask & bd71837_reg_read(c->mfd, c->reg);
+
+}
+
+static unsigned long bd71837_clk_recalc_rate(struct clk_hw *hw,
+                                            unsigned long parent_rate)
+{
+       struct bd71837_clk *c = container_of(hw, struct bd71837_clk, hw);
+
+       return c->rate;
+}
+
+static int bd71837_clk_probe(struct platform_device *pdev)
+{
+       struct bd71837_clk *c;
+       int rval = -ENOMEM;
+       struct bd71837 *mfd = dev_get_drvdata(pdev->dev.parent);
+       const char *errstr = "memory allocation for bd71837 data failed";
+       struct clk_init_data init = {
+               .name = "bd71837-32k-out",
+               .ops = &bd71837_clk_ops,
+       };
+
+       c = kzalloc(sizeof(struct bd71837_clk), GFP_KERNEL);
+       if (!c)
+               goto err_out;
+
+       c->reg = BD71837_REG_OUT32K;
+       c->mask = BD71837_OUT32K_EN;
+       c->rate = BD71837_CLK_RATE;
+       c->mfd = mfd;
+       c->pdev = pdev;
+
+       if (pdev->dev.of_node)
+               of_property_read_string_index(pdev->dev.of_node,
+                                             "clock-output-names", 0,
+                                             &init.name);
+
+       c->hw.init = &init;
+
+       errstr = "failed to register 32K clk";
+       rval = clk_hw_register(&pdev->dev, &c->hw);
+       if (rval)
+               goto err_free;
+
+       errstr = "failed to register clkdev for bd71837";
+       rval = clk_hw_register_clkdev(&c->hw, init.name, NULL);
+       if (rval)
+               goto err_unregister;
+
+       platform_set_drvdata(pdev, c);
+       dev_dbg(&pdev->dev, "bd71837_clk successfully probed\n");
+
+       return 0;
+
+err_unregister:
+       clk_hw_unregister(&c->hw);
+err_free:
+       kfree(c);
+err_out:
+       dev_err(&pdev->dev, "%s\n", errstr);
+       return rval;
+}
+
+static int bd71837_clk_remove(struct platform_device *pdev)
+{
+       struct bd71837_clk *c = platform_get_drvdata(pdev);
+
+       if (c) {
+               clk_hw_unregister(&c->hw);
+               kfree(c);
+               platform_set_drvdata(pdev, NULL);
+       }
+       return 0;
+}
+
+static struct platform_driver bd71837_clk = {
+       .driver = {
+               .name = "bd71837-clk",
+       },
+       .probe = bd71837_clk_probe,
+       .remove = bd71837_clk_remove,
+};
+
+module_platform_driver(bd71837_clk);
+
+MODULE_AUTHOR("Matti Vaittinen <matti.vaitti...@fi.rohmeurope.com>");
+MODULE_DESCRIPTION("BD71837 chip clk driver");
+MODULE_LICENSE("GPL");
-- 
2.14.3

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