clk: imx: lpcg: add suspend/resume support

LPCG clock state may be lost when it's power domain is completely
off during system suspend/resume and we need save and restore the
state properly.

Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This commit is contained in:
Dong Aisheng 2020-07-29 16:00:18 +08:00 committed by Shawn Guo
parent 18cdbad40c
commit ea0c5cbaf8
3 changed files with 39 additions and 0 deletions

View File

@ -364,6 +364,7 @@ static struct platform_driver imx8qxp_lpcg_clk_driver = {
.driver = {
.name = "imx8qxp-lpcg-clk",
.of_match_table = imx8qxp_lpcg_match,
.pm = &imx_clk_lpcg_scu_pm_ops,
.suppress_bind_attrs = true,
},
.probe = imx8qxp_lpcg_clk_probe,

View File

@ -34,6 +34,9 @@ struct clk_lpcg_scu {
void __iomem *reg;
u8 bit_idx;
bool hw_gate;
/* for state save&restore */
u32 state;
};
#define to_clk_lpcg_scu(_hw) container_of(_hw, struct clk_lpcg_scu, hw)
@ -113,6 +116,9 @@ struct clk_hw *__imx_clk_lpcg_scu(struct device *dev, const char *name,
hw = ERR_PTR(ret);
}
if (dev)
dev_set_drvdata(dev, clk);
return hw;
}
@ -123,3 +129,34 @@ void imx_clk_lpcg_scu_unregister(struct clk_hw *hw)
clk_hw_unregister(&clk->hw);
kfree(clk);
}
static int __maybe_unused imx_clk_lpcg_scu_suspend(struct device *dev)
{
struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
clk->state = readl_relaxed(clk->reg);
dev_dbg(dev, "save lpcg state 0x%x\n", clk->state);
return 0;
}
static int __maybe_unused imx_clk_lpcg_scu_resume(struct device *dev)
{
struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
/*
* FIXME: Sometimes writes don't work unless the CPU issues
* them twice
*/
writel(clk->state, clk->reg);
writel(clk->state, clk->reg);
dev_dbg(dev, "restore lpcg state 0x%x\n", clk->state);
return 0;
}
const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops = {
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_clk_lpcg_scu_suspend,
imx_clk_lpcg_scu_resume)
};

View File

@ -11,6 +11,7 @@
#include <linux/of.h>
extern struct list_head imx_scu_clks[];
extern const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops;
int imx_clk_scu_init(struct device_node *np);
struct clk_hw *imx_scu_of_clk_src_get(struct of_phandle_args *clkspec,