CLK: clk-twl6040: Initial clock driver for OMAP4+ McPDM fclk clock

On OMAP4+ platforms the functional clock for the McPDM IP is suplied by
the twl6040 codec (bit clock on the PDM bus).
This common clock driver for twl6040 will register the mcpdm_fclk clock to
be used by the McPDM driver to make sure that the needed clocks are
available when needed.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/Kconfig

@@ -53,4 +53,12 @@ config COMMON_CLK_MAX77686
 	---help---
 	  This driver supports Maxim 77686 crystal oscillator clock. 
 
+config CLK_TWL6040
+	tristate "External McPDM functional clock from twl6040"
+	depends on TWL6040_CORE
+	---help---
+	  Enable the external functional clock support on OMAP4+ platforms for
+	  McPDM. McPDM module is using the external bit clock on the McPDM bus
+	  as functional clock.
+
 endmenu

drivers/clk/Makefile

@@ -23,3 +23,4 @@ obj-$(CONFIG_ARCH_VT8500)	+= clk-vt8500.o
 # Chip specific
 obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o
 obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o
+obj-$(CONFIG_CLK_TWL6040)	+= clk-twl6040.o

drivers/clk/clk-twl6040.c

@@ -0,0 +1,126 @@
+/*
+* TWL6040 clock module driver for OMAP4 McPDM functional clock
+*
+* Copyright (C) 2012 Texas Instruments Inc.
+* Peter Ujfalusi <peter.ujfalusi@ti.com>
+*
+* 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.
+*
+* 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., 51 Franklin St, Fifth Floor, Boston, MA
+* 02110-1301 USA
+*
+*/
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/twl6040.h>
+#include <linux/clk-provider.h>
+
+struct twl6040_clk {
+	struct twl6040 *twl6040;
+	struct device *dev;
+	struct clk_hw mcpdm_fclk;
+	struct clk *clk;
+	int enabled;
+};
+
+static int twl6040_bitclk_is_enabled(struct clk_hw *hw)
+{
+	struct twl6040_clk *twl6040_clk = container_of(hw, struct twl6040_clk,
+						       mcpdm_fclk);
+	return twl6040_clk->enabled;
+}
+
+static int twl6040_bitclk_prepare(struct clk_hw *hw)
+{
+	struct twl6040_clk *twl6040_clk = container_of(hw, struct twl6040_clk,
+						       mcpdm_fclk);
+	int ret;
+
+	ret = twl6040_power(twl6040_clk->twl6040, 1);
+	if (!ret)
+		twl6040_clk->enabled = 1;
+
+	return ret;
+}
+
+static void twl6040_bitclk_unprepare(struct clk_hw *hw)
+{
+	struct twl6040_clk *twl6040_clk = container_of(hw, struct twl6040_clk,
+						       mcpdm_fclk);
+	int ret;
+
+	ret = twl6040_power(twl6040_clk->twl6040, 0);
+	if (!ret)
+		twl6040_clk->enabled = 0;
+}
+
+static const struct clk_ops twl6040_mcpdm_ops = {
+	.is_enabled = twl6040_bitclk_is_enabled,
+	.prepare = twl6040_bitclk_prepare,
+	.unprepare = twl6040_bitclk_unprepare,
+};
+
+static struct clk_init_data wm831x_clkout_init = {
+	.name = "mcpdm_fclk",
+	.ops = &twl6040_mcpdm_ops,
+	.flags = CLK_IS_ROOT,
+};
+
+static int __devinit twl6040_clk_probe(struct platform_device *pdev)
+{
+	struct twl6040 *twl6040 = dev_get_drvdata(pdev->dev.parent);
+	struct twl6040_clk *clkdata;
+
+	clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL);
+	if (!clkdata)
+		return -ENOMEM;
+
+	clkdata->dev = &pdev->dev;
+	clkdata->twl6040 = twl6040;
+
+	clkdata->mcpdm_fclk.init = &wm831x_clkout_init;
+	clkdata->clk = clk_register(&pdev->dev, &clkdata->mcpdm_fclk);
+	if (!clkdata->clk)
+		return -EINVAL;
+
+	dev_set_drvdata(&pdev->dev, clkdata);
+
+	return 0;
+}
+
+static int __devexit twl6040_clk_remove(struct platform_device *pdev)
+{
+	struct twl6040_clk *clkdata = dev_get_drvdata(&pdev->dev);
+
+	clk_unregister(clkdata->clk);
+
+	return 0;
+}
+
+static struct platform_driver twl6040_clk_driver = {
+	.driver = {
+		.name = "twl6040-clk",
+		.owner = THIS_MODULE,
+	},
+	.probe = twl6040_clk_probe,
+	.remove = __devexit_p(twl6040_clk_remove),
+};
+
+module_platform_driver(twl6040_clk_driver);
+
+MODULE_DESCRIPTION("TWL6040 clock driver for McPDM functional clock");
+MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
+MODULE_ALIAS("platform:twl6040-clk");
+MODULE_LICENSE("GPL");