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Message-ID: <1574851595-25663-1-git-send-email-alain.volmat@st.com>
Date: Wed, 27 Nov 2019 11:46:35 +0100
From: Alain Volmat <alain.volmat@...com>
To: <wsa@...-dreams.de>, <robh+dt@...nel.org>
CC: <mark.rutland@....com>, <pierre-yves.mordret@...com>,
<mcoquelin.stm32@...il.com>, <alexandre.torgue@...com>,
<linux-i2c@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-stm32@...md-mailman.stormreply.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <fabrice.gasnier@...com>
Subject: [PATCH 4/4] i2c: i2c-stm32f7: add PM_SLEEP suspend/resume support
Backup/restore I2C registers as part of the suspend/resume
handlers. The device is marked as suspended to ensure that
transfers are rejected during the suspended period.
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@...com>
Signed-off-by: Alain Volmat <alain.volmat@...com>
---
drivers/i2c/busses/i2c-stm32f7.c | 118 +++++++++++++++++++++++++++++++++++++--
1 file changed, 114 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index b2634afe066d..75a3e8107a60 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -169,6 +169,24 @@
#define STM32F7_AUTOSUSPEND_DELAY (HZ / 100)
/**
+ * struct stm32f7_i2c_regs - i2c f7 registers backup
+ * @cr1: Control register 1
+ * @cr2: Control register 2
+ * @oar1: Own address 1 register
+ * @oar2: Own address 2 register
+ * @pecr: PEC register
+ * @tmgr: Timing register
+ */
+struct stm32f7_i2c_regs {
+ u32 cr1;
+ u32 cr2;
+ u32 oar1;
+ u32 oar2;
+ u32 pecr;
+ u32 tmgr;
+};
+
+/**
* struct stm32f7_i2c_spec - private i2c specification timing
* @rate: I2C bus speed (Hz)
* @rate_min: 80% of I2C bus speed (Hz)
@@ -298,6 +316,7 @@ struct stm32f7_i2c_dev {
struct stm32f7_i2c_timings timing;
struct i2c_client *slave[STM32F7_I2C_MAX_SLAVE];
struct i2c_client *slave_running;
+ struct stm32f7_i2c_regs regs;
u32 slave_dir;
bool master_mode;
struct stm32_i2c_dma *dma;
@@ -2027,8 +2046,7 @@ static int stm32f7_i2c_remove(struct platform_device *pdev)
return 0;
}
-#ifdef CONFIG_PM
-static int stm32f7_i2c_runtime_suspend(struct device *dev)
+static int __maybe_unused stm32f7_i2c_runtime_suspend(struct device *dev)
{
struct stm32f7_i2c_dev *i2c_dev = dev_get_drvdata(dev);
@@ -2038,7 +2056,7 @@ static int stm32f7_i2c_runtime_suspend(struct device *dev)
return 0;
}
-static int stm32f7_i2c_runtime_resume(struct device *dev)
+static int __maybe_unused stm32f7_i2c_runtime_resume(struct device *dev)
{
struct stm32f7_i2c_dev *i2c_dev = dev_get_drvdata(dev);
int ret;
@@ -2053,11 +2071,103 @@ static int stm32f7_i2c_runtime_resume(struct device *dev)
return 0;
}
-#endif
+
+static int __maybe_unused
+stm32f7_i2c_regs_backup(struct stm32f7_i2c_dev *i2c_dev)
+{
+ int ret;
+
+ ret = pm_runtime_get_sync(i2c_dev->dev);
+ if (ret < 0)
+ return ret;
+
+ i2c_dev->regs.cr1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR1);
+ i2c_dev->regs.cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2);
+ i2c_dev->regs.oar1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR1);
+ i2c_dev->regs.oar2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR2);
+ i2c_dev->regs.pecr = readl_relaxed(i2c_dev->base + STM32F7_I2C_PECR);
+ i2c_dev->regs.tmgr = readl_relaxed(i2c_dev->base + STM32F7_I2C_TIMINGR);
+
+ pm_runtime_put_sync(i2c_dev->dev);
+
+ return ret;
+}
+
+static int __maybe_unused
+stm32f7_i2c_regs_restore(struct stm32f7_i2c_dev *i2c_dev)
+{
+ u32 cr1;
+ int ret;
+
+ ret = pm_runtime_get_sync(i2c_dev->dev);
+ if (ret < 0)
+ return ret;
+
+ cr1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR1);
+ if (cr1 & STM32F7_I2C_CR1_PE)
+ stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1,
+ STM32F7_I2C_CR1_PE);
+
+ writel_relaxed(i2c_dev->regs.tmgr, i2c_dev->base + STM32F7_I2C_TIMINGR);
+ writel_relaxed(i2c_dev->regs.cr1 & ~STM32F7_I2C_CR1_PE,
+ i2c_dev->base + STM32F7_I2C_CR1);
+ if (i2c_dev->regs.cr1 & STM32F7_I2C_CR1_PE)
+ stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
+ STM32F7_I2C_CR1_PE);
+ writel_relaxed(i2c_dev->regs.cr2, i2c_dev->base + STM32F7_I2C_CR2);
+ writel_relaxed(i2c_dev->regs.oar1, i2c_dev->base + STM32F7_I2C_OAR1);
+ writel_relaxed(i2c_dev->regs.oar2, i2c_dev->base + STM32F7_I2C_OAR2);
+ writel_relaxed(i2c_dev->regs.pecr, i2c_dev->base + STM32F7_I2C_PECR);
+
+ pm_runtime_put_sync(i2c_dev->dev);
+
+ return ret;
+}
+
+static int __maybe_unused stm32f7_i2c_suspend(struct device *dev)
+{
+ struct stm32f7_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+ int ret;
+
+ i2c_mark_adapter_suspended(&i2c_dev->adap);
+ ret = stm32f7_i2c_regs_backup(i2c_dev);
+ if (ret < 0) {
+ i2c_mark_adapter_resumed(&i2c_dev->adap);
+ return ret;
+ }
+
+ if (!stm32f7_i2c_is_slave_registered(i2c_dev)) {
+ pinctrl_pm_select_sleep_state(dev);
+ pm_runtime_force_suspend(dev);
+ }
+
+ return 0;
+}
+
+static int __maybe_unused stm32f7_i2c_resume(struct device *dev)
+{
+ struct stm32f7_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+ int ret;
+
+ if (!stm32f7_i2c_is_slave_registered(i2c_dev)) {
+ ret = pm_runtime_force_resume(dev);
+ if (ret < 0)
+ return ret;
+ pinctrl_pm_select_default_state(dev);
+ }
+
+ ret = stm32f7_i2c_regs_restore(i2c_dev);
+ if (ret < 0)
+ return ret;
+ i2c_mark_adapter_resumed(&i2c_dev->adap);
+
+ return 0;
+}
static const struct dev_pm_ops stm32f7_i2c_pm_ops = {
SET_RUNTIME_PM_OPS(stm32f7_i2c_runtime_suspend,
stm32f7_i2c_runtime_resume, NULL)
+ SET_SYSTEM_SLEEP_PM_OPS(stm32f7_i2c_suspend, stm32f7_i2c_resume)
};
static const struct of_device_id stm32f7_i2c_match[] = {
--
2.7.4
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