[PATCH 1/2] i2c: uniphier: add PM suspend / resume support

From: Masahiro Yamada
Date: Mon Jul 31 2017 - 00:52:30 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>
---

drivers/i2c/busses/i2c-uniphier.c | 40 ++++++++++++++++++++++++++++++++++-----
1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-uniphier.c b/drivers/i2c/busses/i2c-uniphier.c
index 777c0fe93653..f41a09d9927a 100644
--- a/drivers/i2c/busses/i2c-uniphier.c
+++ b/drivers/i2c/busses/i2c-uniphier.c
@@ -53,6 +53,7 @@ struct uniphier_i2c_priv {
void __iomem *membase;
struct clk *clk;
unsigned int busy_cnt;
+ unsigned int clk_cycle;
};

static irqreturn_t uniphier_i2c_interrupt(int irq, void *dev_id)
@@ -316,13 +317,13 @@ static struct i2c_bus_recovery_info uniphier_i2c_bus_recovery_info = {
.unprepare_recovery = uniphier_i2c_unprepare_recovery,
};

-static void uniphier_i2c_hw_init(struct uniphier_i2c_priv *priv,
- u32 bus_speed, unsigned long clk_rate)
+static void uniphier_i2c_hw_init(struct uniphier_i2c_priv *priv)
{
+ unsigned int cyc = priv->clk_cycle;
+
uniphier_i2c_reset(priv, true);

- writel((clk_rate / bus_speed / 2 << 16) | (clk_rate / bus_speed),
- priv->membase + UNIPHIER_I2C_CLK);
+ writel((cyc / 2 << 16) | cyc, priv->membase + UNIPHIER_I2C_CLK);

uniphier_i2c_reset(priv, false);
}
@@ -376,6 +377,7 @@ static int uniphier_i2c_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_i2c_algo;
@@ -386,7 +388,7 @@ static int uniphier_i2c_probe(struct platform_device *pdev)
i2c_set_adapdata(&priv->adap, priv);
platform_set_drvdata(pdev, priv);

- uniphier_i2c_hw_init(priv, bus_speed, clk_rate);
+ uniphier_i2c_hw_init(priv);

ret = devm_request_irq(dev, irq, uniphier_i2c_interrupt, 0, pdev->name,
priv);
@@ -413,6 +415,33 @@ static int uniphier_i2c_remove(struct platform_device *pdev)
return 0;
}

+static int uniphier_i2c_suspend(struct device *dev)
+{
+ struct uniphier_i2c_priv *priv = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static int uniphier_i2c_resume(struct device *dev)
+{
+ struct uniphier_i2c_priv *priv = dev_get_drvdata(dev);
+ int ret;
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ return ret;
+
+ uniphier_i2c_hw_init(priv);
+
+ return 0;
+}
+
+static const struct dev_pm_ops uniphier_i2c_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(uniphier_i2c_suspend, uniphier_i2c_resume)
+};
+
static const struct of_device_id uniphier_i2c_match[] = {
{ .compatible = "socionext,uniphier-i2c" },
{ /* sentinel */ }
@@ -425,6 +454,7 @@ static struct platform_driver uniphier_i2c_drv = {
.driver = {
.name = "uniphier-i2c",
.of_match_table = uniphier_i2c_match,
+ .pm = &uniphier_i2c_pm_ops,
},
};
module_platform_driver(uniphier_i2c_drv);
--
2.7.4