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linux-next/drivers/clk/clk-twl6040.c
Tony Lindgren 5ae51d67ae clk: clk-twl6040: Fix imprecise external abort for pdmclk
I noticed that modprobe clk-twl6040 can fail after a cold boot with:
abe_cm:clk:0010:0: failed to enable
...
Unhandled fault: imprecise external abort (0x1406) at 0xbe896b20

WARNING: CPU: 1 PID: 29 at drivers/clk/clk.c:828 clk_core_disable_lock+0x18/0x24
...
(clk_core_disable_lock) from [<c0123534>] (_disable_clocks+0x18/0x90)
(_disable_clocks) from [<c0124040>] (_idle+0x17c/0x244)
(_idle) from [<c0125ad4>] (omap_hwmod_idle+0x24/0x44)
(omap_hwmod_idle) from [<c053a038>] (sysc_runtime_suspend+0x48/0x108)
(sysc_runtime_suspend) from [<c06084c4>] (__rpm_callback+0x144/0x1d8)
(__rpm_callback) from [<c0608578>] (rpm_callback+0x20/0x80)
(rpm_callback) from [<c0607034>] (rpm_suspend+0x120/0x694)
(rpm_suspend) from [<c0607a78>] (__pm_runtime_idle+0x60/0x84)
(__pm_runtime_idle) from [<c053aaf0>] (sysc_probe+0x874/0xf2c)
(sysc_probe) from [<c05fecd4>] (platform_drv_probe+0x48/0x98)

After searching around for a similar issue, I came across an earlier fix
that never got merged upstream in the Android tree for glass-omap-xrr02.
There is patch "MFD: twl6040-codec: Implement PDMCLK cold temp errata"
by Misael Lopez Cruz <misael.lopez@ti.com>.

Based on my observations, this fix is also needed when cold booting
devices, and not just for deeper idle modes. Since we now have a clock
driver for pdmclk, let's fix the issue in twl6040_pdmclk_prepare().

Cc: Misael Lopez Cruz <misael.lopez@ti.com>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2019-02-21 14:11:23 -08:00

177 lines
4.3 KiB
C

/*
* 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 const 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 devm_of_clk_add_hw_provider(&pdev->dev, 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");