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/*
* 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/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/mfd/twl6040.h>
#include <linux/clk-provider.h>
struct twl6040_pdmclk {
struct twl6040 *twl6040;
struct device *dev;
struct clk_hw pdmclk_hw;
int enabled;
};
static int twl6040_pdmclk_is_prepared(struct clk_hw *hw)
{
struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
pdmclk_hw);
return pdmclk->enabled;
}
static int twl6040_pdmclk_reset_one_clock(struct twl6040_pdmclk *pdmclk,
unsigned int reg)
{
const u8 reset_mask = TWL6040_HPLLRST; /* Same for HPPLL and LPPLL */
int ret;
ret = twl6040_set_bits(pdmclk->twl6040, reg, reset_mask);
if (ret < 0)
return ret;
ret = twl6040_clear_bits(pdmclk->twl6040, reg, reset_mask);
if (ret < 0)
return ret;
return 0;
}
/*
* TWL6040A2 Phoenix Audio IC erratum #6: "PDM Clock Generation Issue At
* Cold Temperature". This affects cold boot and deeper idle states it
* seems. The workaround consists of resetting HPPLL and LPPLL.
*/
static int twl6040_pdmclk_quirk_reset_clocks(struct twl6040_pdmclk *pdmclk)
{
int ret;
ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_HPPLLCTL);
if (ret)
return ret;
ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_LPPLLCTL);
if (ret)
return ret;
return 0;
}
static int twl6040_pdmclk_prepare(struct clk_hw *hw)
{
struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
pdmclk_hw);
int ret;
ret = twl6040_power(pdmclk->twl6040, 1);
if (ret)
return ret;
ret = twl6040_pdmclk_quirk_reset_clocks(pdmclk);
if (ret)
goto out_err;
pdmclk->enabled = 1;
return 0;
out_err:
dev_err(pdmclk->dev, "%s: error %i\n", __func__, ret);
twl6040_power(pdmclk->twl6040, 0);
return ret;
}
static void twl6040_pdmclk_unprepare(struct clk_hw *hw)
{
struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
pdmclk_hw);
int ret;
ret = twl6040_power(pdmclk->twl6040, 0);
if (!ret)
pdmclk->enabled = 0;
}
static unsigned long twl6040_pdmclk_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
pdmclk_hw);
return twl6040_get_sysclk(pdmclk->twl6040);
}
static const struct clk_ops twl6040_pdmclk_ops = {
.is_prepared = twl6040_pdmclk_is_prepared,
.prepare = twl6040_pdmclk_prepare,
.unprepare = twl6040_pdmclk_unprepare,
.recalc_rate = twl6040_pdmclk_recalc_rate,
};
static struct clk_init_data twl6040_pdmclk_init = {
.name = "pdmclk",
.ops = &twl6040_pdmclk_ops,
.flags = CLK_GET_RATE_NOCACHE,
};
static int twl6040_pdmclk_probe(struct platform_device *pdev)
{
struct twl6040 *twl6040 = dev_get_drvdata(pdev->dev.parent);
struct twl6040_pdmclk *clkdata;
int ret;
clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL);
if (!clkdata)
return -ENOMEM;
clkdata->dev = &pdev->dev;
clkdata->twl6040 = twl6040;
clkdata->pdmclk_hw.init = &twl6040_pdmclk_init;
ret = devm_clk_hw_register(&pdev->dev, &clkdata->pdmclk_hw);
if (ret)
return ret;
platform_set_drvdata(pdev, clkdata);
return of_clk_add_hw_provider(pdev->dev.parent->of_node,
of_clk_hw_simple_get,
&clkdata->pdmclk_hw);
}
static struct platform_driver twl6040_pdmclk_driver = {
.driver = {
.name = "twl6040-pdmclk",
},
.probe = twl6040_pdmclk_probe,
};
module_platform_driver(twl6040_pdmclk_driver);
MODULE_DESCRIPTION("TWL6040 clock driver for McPDM functional clock");
MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
MODULE_ALIAS("platform:twl6040-pdmclk");
MODULE_LICENSE("GPL");
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