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path: root/drivers/i2c/busses/i2c-bcm2835.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-bcm2835.c')
-rw-r--r--drivers/i2c/busses/i2c-bcm2835.c90
1 files changed, 51 insertions, 39 deletions
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index d9b86fcc3825..0d7e2654a534 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * BCM2835 master mode driver
+ * BCM2835 I2C controller driver
*/
#include <linux/clk.h>
@@ -12,7 +12,7 @@
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
-#include <linux/of_device.h>
+#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
@@ -23,6 +23,11 @@
#define BCM2835_I2C_FIFO 0x10
#define BCM2835_I2C_DIV 0x14
#define BCM2835_I2C_DEL 0x18
+/*
+ * 16-bit field for the number of SCL cycles to wait after rising SCL
+ * before deciding the target is not responding. 0 disables the
+ * timeout detection.
+ */
#define BCM2835_I2C_CLKT 0x1c
#define BCM2835_I2C_C_READ BIT(0)
@@ -132,12 +137,14 @@ static int clk_bcm2835_i2c_set_rate(struct clk_hw *hw, unsigned long rate,
return 0;
}
-static long clk_bcm2835_i2c_round_rate(struct clk_hw *hw, unsigned long rate,
- unsigned long *parent_rate)
+static int clk_bcm2835_i2c_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
{
- u32 divider = clk_bcm2835_i2c_calc_divider(rate, *parent_rate);
+ u32 divider = clk_bcm2835_i2c_calc_divider(req->rate, req->best_parent_rate);
+
+ req->rate = DIV_ROUND_UP(req->best_parent_rate, divider);
- return DIV_ROUND_UP(*parent_rate, divider);
+ return 0;
}
static unsigned long clk_bcm2835_i2c_recalc_rate(struct clk_hw *hw,
@@ -151,7 +158,7 @@ static unsigned long clk_bcm2835_i2c_recalc_rate(struct clk_hw *hw,
static const struct clk_ops clk_bcm2835_i2c_ops = {
.set_rate = clk_bcm2835_i2c_set_rate,
- .round_rate = clk_bcm2835_i2c_round_rate,
+ .determine_rate = clk_bcm2835_i2c_determine_rate,
.recalc_rate = clk_bcm2835_i2c_recalc_rate,
};
@@ -218,7 +225,7 @@ static void bcm2835_drain_rxfifo(struct bcm2835_i2c_dev *i2c_dev)
/*
* Repeated Start Condition (Sr)
* The BCM2835 ARM Peripherals datasheet mentions a way to trigger a Sr when it
- * talks about reading from a slave with 10 bit address. This is achieved by
+ * talks about reading from a target with 10 bit address. This is achieved by
* issuing a write, poll the I2CS.TA flag and wait for it to be set, and then
* issue a read.
* A comment in https://github.com/raspberrypi/linux/issues/254 shows how the
@@ -365,7 +372,6 @@ static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
if (!time_left) {
bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C,
BCM2835_I2C_C_CLEAR);
- dev_err(i2c_dev->dev, "i2c transfer timed out\n");
return -ETIMEDOUT;
}
@@ -386,13 +392,13 @@ static u32 bcm2835_i2c_func(struct i2c_adapter *adap)
}
static const struct i2c_algorithm bcm2835_i2c_algo = {
- .master_xfer = bcm2835_i2c_xfer,
- .functionality = bcm2835_i2c_func,
+ .xfer = bcm2835_i2c_xfer,
+ .functionality = bcm2835_i2c_func,
};
/*
* The BCM2835 was reported to have problems with clock stretching:
- * http://www.advamation.com/knowhow/raspberrypi/rpi-i2c-bug.html
+ * https://www.advamation.com/knowhow/raspberrypi/rpi-i2c-bug.html
* https://www.raspberrypi.org/forums/viewtopic.php?p=146272
*/
static const struct i2c_adapter_quirks bcm2835_i2c_quirks = {
@@ -402,7 +408,6 @@ static const struct i2c_adapter_quirks bcm2835_i2c_quirks = {
static int bcm2835_i2c_probe(struct platform_device *pdev)
{
struct bcm2835_i2c_dev *i2c_dev;
- struct resource *mem, *irq;
int ret;
struct i2c_adapter *adap;
struct clk *mclk;
@@ -415,24 +420,20 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
i2c_dev->dev = &pdev->dev;
init_completion(&i2c_dev->completion);
- mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- i2c_dev->regs = devm_ioremap_resource(&pdev->dev, mem);
+ i2c_dev->regs = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
if (IS_ERR(i2c_dev->regs))
return PTR_ERR(i2c_dev->regs);
mclk = devm_clk_get(&pdev->dev, NULL);
- if (IS_ERR(mclk)) {
- if (PTR_ERR(mclk) != -EPROBE_DEFER)
- dev_err(&pdev->dev, "Could not get clock\n");
- return PTR_ERR(mclk);
- }
+ if (IS_ERR(mclk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(mclk),
+ "Could not get clock\n");
i2c_dev->bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk, i2c_dev);
- if (IS_ERR(i2c_dev->bus_clk)) {
- dev_err(&pdev->dev, "Could not register clock\n");
- return PTR_ERR(i2c_dev->bus_clk);
- }
+ if (IS_ERR(i2c_dev->bus_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(i2c_dev->bus_clk),
+ "Could not register clock\n");
ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
&bus_clk_rate);
@@ -443,29 +444,27 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
}
ret = clk_set_rate_exclusive(i2c_dev->bus_clk, bus_clk_rate);
- if (ret < 0) {
- dev_err(&pdev->dev, "Could not set clock frequency\n");
- return ret;
- }
+ if (ret < 0)
+ return dev_err_probe(&pdev->dev, ret,
+ "Could not set clock frequency\n");
ret = clk_prepare_enable(i2c_dev->bus_clk);
if (ret) {
dev_err(&pdev->dev, "Couldn't prepare clock");
- return ret;
+ goto err_put_exclusive_rate;
}
- irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
- if (!irq) {
- dev_err(&pdev->dev, "No IRQ resource\n");
- return -ENODEV;
+ i2c_dev->irq = platform_get_irq(pdev, 0);
+ if (i2c_dev->irq < 0) {
+ ret = i2c_dev->irq;
+ goto err_disable_unprepare_clk;
}
- i2c_dev->irq = irq->start;
ret = request_irq(i2c_dev->irq, bcm2835_i2c_isr, IRQF_SHARED,
dev_name(&pdev->dev), i2c_dev);
if (ret) {
dev_err(&pdev->dev, "Could not request IRQ\n");
- return -ENODEV;
+ goto err_disable_unprepare_clk;
}
adap = &i2c_dev->adapter;
@@ -479,16 +478,31 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
adap->dev.of_node = pdev->dev.of_node;
adap->quirks = of_device_get_match_data(&pdev->dev);
+ /*
+ * Disable the hardware clock stretching timeout. SMBUS
+ * specifies a limit for how long the device can stretch the
+ * clock, but core I2C doesn't.
+ */
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_CLKT, 0);
bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, 0);
ret = i2c_add_adapter(adap);
if (ret)
- free_irq(i2c_dev->irq, i2c_dev);
+ goto err_free_irq;
+
+ return 0;
+
+err_free_irq:
+ free_irq(i2c_dev->irq, i2c_dev);
+err_disable_unprepare_clk:
+ clk_disable_unprepare(i2c_dev->bus_clk);
+err_put_exclusive_rate:
+ clk_rate_exclusive_put(i2c_dev->bus_clk);
return ret;
}
-static int bcm2835_i2c_remove(struct platform_device *pdev)
+static void bcm2835_i2c_remove(struct platform_device *pdev)
{
struct bcm2835_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
@@ -497,8 +511,6 @@ static int bcm2835_i2c_remove(struct platform_device *pdev)
free_irq(i2c_dev->irq, i2c_dev);
i2c_del_adapter(&i2c_dev->adapter);
-
- return 0;
}
static const struct of_device_id bcm2835_i2c_of_match[] = {
generated by cgit (git 2.34.1) at 2025-12-27 06:05:06 +0000