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Message-ID: <1616998145-28278-3-git-send-email-alain.volmat@foss.st.com>
Date: Mon, 29 Mar 2021 08:09:05 +0200
From: Alain Volmat <alain.volmat@...s.st.com>
To: <wsa@...nel.org>, <robh+dt@...nel.org>
CC: <mark.rutland@....com>, <pierre-yves.mordret@...s.st.com>,
<mcoquelin.stm32@...il.com>, <alexandre.torgue@...s.st.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@...s.st.com>,
<alain.volmat@...s.st.com>
Subject: [PATCH v3 2/2] i2c: stm32f7: add SMBus-Alert support
Add support for the SMBus-Alert protocol to the STM32F7 that has
dedicated control and status logic.
If SMBus-Alert is used, the SMBALERT# pin must be configured as alternate
function for I2C Alert.
Signed-off-by: Alain Volmat <alain.volmat@...s.st.com>
Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@...s.st.com>
---
v2: - rely on st,smbus-alert binding instead of smbus
---
drivers/i2c/busses/i2c-stm32f7.c | 73 ++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index c62c815b88eb..bd840cd2b9e4 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -51,6 +51,7 @@
/* STM32F7 I2C control 1 */
#define STM32F7_I2C_CR1_PECEN BIT(23)
+#define STM32F7_I2C_CR1_ALERTEN BIT(22)
#define STM32F7_I2C_CR1_SMBHEN BIT(20)
#define STM32F7_I2C_CR1_WUPEN BIT(18)
#define STM32F7_I2C_CR1_SBC BIT(16)
@@ -125,6 +126,7 @@
(((n) & STM32F7_I2C_ISR_ADDCODE_MASK) >> 17)
#define STM32F7_I2C_ISR_DIR BIT(16)
#define STM32F7_I2C_ISR_BUSY BIT(15)
+#define STM32F7_I2C_ISR_ALERT BIT(13)
#define STM32F7_I2C_ISR_PECERR BIT(11)
#define STM32F7_I2C_ISR_ARLO BIT(9)
#define STM32F7_I2C_ISR_BERR BIT(8)
@@ -138,6 +140,7 @@
#define STM32F7_I2C_ISR_TXE BIT(0)
/* STM32F7 I2C Interrupt Clear */
+#define STM32F7_I2C_ICR_ALERTCF BIT(13)
#define STM32F7_I2C_ICR_PECCF BIT(11)
#define STM32F7_I2C_ICR_ARLOCF BIT(9)
#define STM32F7_I2C_ICR_BERRCF BIT(8)
@@ -283,6 +286,17 @@ struct stm32f7_i2c_msg {
u8 smbus_buf[I2C_SMBUS_BLOCK_MAX + 3] __aligned(4);
};
+/**
+ * struct stm32f7_i2c_alert - SMBus alert specific data
+ * @setup: platform data for the smbus_alert i2c client
+ * @ara: I2C slave device used to respond to the SMBus Alert with Alert
+ * Response Address
+ */
+struct stm32f7_i2c_alert {
+ struct i2c_smbus_alert_setup setup;
+ struct i2c_client *ara;
+};
+
/**
* struct stm32f7_i2c_dev - private data of the controller
* @adap: I2C adapter for this controller
@@ -312,6 +326,7 @@ struct stm32f7_i2c_msg {
* @wakeup_src: boolean to know if the device is a wakeup source
* @smbus_mode: states that the controller is configured in SMBus mode
* @host_notify_client: SMBus host-notify client
+ * @alert: SMBus alert specific data
*/
struct stm32f7_i2c_dev {
struct i2c_adapter adap;
@@ -340,6 +355,7 @@ struct stm32f7_i2c_dev {
bool wakeup_src;
bool smbus_mode;
struct i2c_client *host_notify_client;
+ struct stm32f7_i2c_alert *alert;
};
/*
@@ -1616,6 +1632,13 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data)
f7_msg->result = -EINVAL;
}
+ if (status & STM32F7_I2C_ISR_ALERT) {
+ dev_dbg(dev, "<%s>: SMBus alert received\n", __func__);
+ writel_relaxed(STM32F7_I2C_ICR_ALERTCF, base + STM32F7_I2C_ICR);
+ i2c_handle_smbus_alert(i2c_dev->alert->ara);
+ return IRQ_HANDLED;
+ }
+
if (!i2c_dev->slave_running) {
u32 mask;
/* Disable interrupts */
@@ -1982,6 +2005,42 @@ static void stm32f7_i2c_disable_smbus_host(struct stm32f7_i2c_dev *i2c_dev)
}
}
+static int stm32f7_i2c_enable_smbus_alert(struct stm32f7_i2c_dev *i2c_dev)
+{
+ struct stm32f7_i2c_alert *alert;
+ struct i2c_adapter *adap = &i2c_dev->adap;
+ struct device *dev = i2c_dev->dev;
+ void __iomem *base = i2c_dev->base;
+
+ alert = devm_kzalloc(dev, sizeof(*alert), GFP_KERNEL);
+ if (!alert)
+ return -ENOMEM;
+
+ alert->ara = i2c_new_smbus_alert_device(adap, &alert->setup);
+ if (IS_ERR(alert->ara))
+ return PTR_ERR(alert->ara);
+
+ i2c_dev->alert = alert;
+
+ /* Enable SMBus Alert */
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, STM32F7_I2C_CR1_ALERTEN);
+
+ return 0;
+}
+
+static void stm32f7_i2c_disable_smbus_alert(struct stm32f7_i2c_dev *i2c_dev)
+{
+ struct stm32f7_i2c_alert *alert = i2c_dev->alert;
+ void __iomem *base = i2c_dev->base;
+
+ if (alert) {
+ /* Disable SMBus Alert */
+ stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR1,
+ STM32F7_I2C_CR1_ALERTEN);
+ i2c_unregister_device(alert->ara);
+ }
+}
+
static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
{
struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
@@ -2169,6 +2228,16 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
}
}
+ if (of_property_read_bool(pdev->dev.of_node, "st,smbus-alert")) {
+ ret = stm32f7_i2c_enable_smbus_alert(i2c_dev);
+ if (ret) {
+ dev_err(i2c_dev->dev,
+ "failed to enable SMBus alert protocol (%d)\n",
+ ret);
+ goto i2c_disable_smbus_host;
+ }
+ }
+
dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\n", adap->nr);
pm_runtime_mark_last_busy(i2c_dev->dev);
@@ -2176,6 +2245,9 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
return 0;
+i2c_disable_smbus_host:
+ stm32f7_i2c_disable_smbus_host(i2c_dev);
+
i2c_adapter_remove:
i2c_del_adapter(adap);
@@ -2210,6 +2282,7 @@ static int stm32f7_i2c_remove(struct platform_device *pdev)
{
struct stm32f7_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+ stm32f7_i2c_disable_smbus_alert(i2c_dev);
stm32f7_i2c_disable_smbus_host(i2c_dev);
i2c_del_adapter(&i2c_dev->adap);
--
2.17.1
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