[PATCH v2 2/2] i2c: uniphier-f: add suspend / resume support

From: Masahiro Yamada
Date: Mon Jul 31 2017 - 01:54:49 EST


When resuming, set up registers that have been lost in the sleep state.
Also, add clock handling in the resume / suspend hooks.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---

Changes in v2:
- Fix define but not used warning

drivers/i2c/busses/i2c-uniphier-f.c | 46 +++++++++++++++++++++++++++++--------
1 file changed, 37 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c
index beee31892295..9918bdd81619 100644
--- a/drivers/i2c/busses/i2c-uniphier-f.c
+++ b/drivers/i2c/busses/i2c-uniphier-f.c
@@ -97,6 +97,7 @@ struct uniphier_fi2c_priv {
int error;
unsigned int flags;
unsigned int busy_cnt;
+ unsigned int clk_cycle;
};

static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
@@ -461,9 +462,9 @@ static struct i2c_bus_recovery_info uniphier_fi2c_bus_recovery_info = {
.unprepare_recovery = uniphier_fi2c_unprepare_recovery,
};

-static void uniphier_fi2c_hw_init(struct uniphier_fi2c_priv *priv,
- u32 bus_speed, unsigned long clk_rate)
+static void uniphier_fi2c_hw_init(struct uniphier_fi2c_priv *priv)
{
+ unsigned int cyc = priv->clk_cycle;
u32 tmp;

tmp = readl(priv->membase + UNIPHIER_FI2C_CR);
@@ -472,12 +473,10 @@ static void uniphier_fi2c_hw_init(struct uniphier_fi2c_priv *priv,

uniphier_fi2c_reset(priv);

- tmp = clk_rate / bus_speed;
-
- writel(tmp, priv->membase + UNIPHIER_FI2C_CYC);
- writel(tmp / 2, priv->membase + UNIPHIER_FI2C_LCTL);
- writel(tmp / 2, priv->membase + UNIPHIER_FI2C_SSUT);
- writel(tmp / 16, priv->membase + UNIPHIER_FI2C_DSUT);
+ writel(cyc, priv->membase + UNIPHIER_FI2C_CYC);
+ writel(cyc / 2, priv->membase + UNIPHIER_FI2C_LCTL);
+ writel(cyc / 2, priv->membase + UNIPHIER_FI2C_SSUT);
+ writel(cyc / 16, priv->membase + UNIPHIER_FI2C_DSUT);

uniphier_fi2c_prepare_operation(priv);
}
@@ -531,6 +530,7 @@ static int uniphier_fi2c_probe(struct platform_device *pdev)
goto disable_clk;
}

+ priv->clk_cycle = clk_rate / bus_speed;
init_completion(&priv->comp);
priv->adap.owner = THIS_MODULE;
priv->adap.algo = &uniphier_fi2c_algo;
@@ -541,7 +541,7 @@ static int uniphier_fi2c_probe(struct platform_device *pdev)
i2c_set_adapdata(&priv->adap, priv);
platform_set_drvdata(pdev, priv);

- uniphier_fi2c_hw_init(priv, bus_speed, clk_rate);
+ uniphier_fi2c_hw_init(priv);

ret = devm_request_irq(dev, irq, uniphier_fi2c_interrupt, 0,
pdev->name, priv);
@@ -568,6 +568,33 @@ static int uniphier_fi2c_remove(struct platform_device *pdev)
return 0;
}

+static int __maybe_unused uniphier_fi2c_suspend(struct device *dev)
+{
+ struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static int __maybe_unused uniphier_fi2c_resume(struct device *dev)
+{
+ struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
+ int ret;
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ return ret;
+
+ uniphier_fi2c_hw_init(priv);
+
+ return 0;
+}
+
+static const struct dev_pm_ops uniphier_fi2c_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(uniphier_fi2c_suspend, uniphier_fi2c_resume)
+};
+
static const struct of_device_id uniphier_fi2c_match[] = {
{ .compatible = "socionext,uniphier-fi2c" },
{ /* sentinel */ }
@@ -580,6 +607,7 @@ static struct platform_driver uniphier_fi2c_drv = {
.driver = {
.name = "uniphier-fi2c",
.of_match_table = uniphier_fi2c_match,
+ .pm = &uniphier_fi2c_pm_ops,
},
};
module_platform_driver(uniphier_fi2c_drv);
--
2.7.4