| Message ID | 20171030034438.26482-1-joel@jms.id.au |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [v3] i2c: aspeed: Deassert reset in probe | expand |
> #include <linux/clk.h> > #include <linux/completion.h> > +#include <linux/delay.h> Sorry, I missed it from previous reviews, but why is delay.h needed? > + bus->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); > + if (IS_ERR(bus->rst)) { > + dev_err(&pdev->dev, "invalid reset controller in device tree"); > + bus->rst = NULL; > + } else > + reset_control_deassert(bus->rst); checkpatch --strict says: CHECK: braces {} should be used on all arms of this statement
On Mon, Oct 30, 2017 at 4:44 AM, Joel Stanley <joel@jms.id.au> wrote: > In order to use i2c from a cold boot, the i2c peripheral must be taken > out of reset. We request a shared reset controller each time a bus > driver is loaded, as the reset is shared between the 14 i2c buses. > > On remove the reset is asserted, which only touches the hardware once > the last i2c bus is removed. > > The request is optional, so if a device tree does not specify a reset > controller (or the driver is not built in), the driver continues to > probe. > > Reviewed-by: Brendan Higgins <brendanhiggins@google.com> > Reviewed-by: Philipp Zabel <philipp.zabel@gmail.com> > Signed-off-by: Joel Stanley <joel@jms.id.au> > --- > v3: Check for bad reset controller probe (caused by eg. bad device tree) > and set ->rst to NULL so assert/desassert does not cause a warning to > be printed > v2: Sort the headers > --- > drivers/i2c/busses/i2c-aspeed.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c > index 284f8670dbeb..5dec00d663eb 100644 > --- a/drivers/i2c/busses/i2c-aspeed.c > +++ b/drivers/i2c/busses/i2c-aspeed.c > @@ -12,6 +12,7 @@ > > #include <linux/clk.h> > #include <linux/completion.h> > +#include <linux/delay.h> > #include <linux/err.h> > #include <linux/errno.h> > #include <linux/i2c.h> > @@ -27,6 +28,7 @@ > #include <linux/of_irq.h> > #include <linux/of_platform.h> > #include <linux/platform_device.h> > +#include <linux/reset.h> > #include <linux/slab.h> > > /* I2C Register */ > @@ -132,6 +134,7 @@ struct aspeed_i2c_bus { > struct i2c_adapter adap; > struct device *dev; > void __iomem *base; > + struct reset_control *rst; > /* Synchronizes I/O mem access to base. */ > spinlock_t lock; > struct completion cmd_complete; > @@ -847,6 +850,13 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev) > /* We just need the clock rate, we don't actually use the clk object. */ > devm_clk_put(&pdev->dev, parent_clk); > > + bus->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); > + if (IS_ERR(bus->rst)) { > + dev_err(&pdev->dev, "invalid reset controller in device tree"); > + bus->rst = NULL; > + } else > + reset_control_deassert(bus->rst); devm_reset_control_get_optional_shared returns NULL if no reset is given in the device tree, and reset_control_deassert will just ignore a NULL parameter. I would suggest to change this to: bus->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); if (IS_ERR(bus->rst)) { dev_err(&pdev->dev, "invalid reset controller in device tree"); return PTR_ERR(bus->rst); } reset_control_deassert(bus->rst); > + > ret = of_property_read_u32(pdev->dev.of_node, > "bus-frequency", &bus->bus_frequency); > if (ret < 0) { > @@ -919,6 +929,8 @@ static int aspeed_i2c_remove_bus(struct platform_device *pdev) > > i2c_del_adapter(&bus->adap); > > + reset_control_assert(bus->rst); > + > return 0; > } > > -- > 2.14.1 regards Philipp
On Mon, 2017-10-30 at 15:24 +0100, Wolfram Sang wrote: > checkpatch --strict says: > > CHECK: braces {} should be used on all arms of this statement And checkpatch should die a horrible death, so what ? :-) Sorry, I can't help but trolling here when checkpatch enforce obviously disgusting and wasteful coding style. Ben.
> > CHECK: braces {} should be used on all arms of this statement > > And checkpatch should die a horrible death, so what ? :-) I buy this to some degree... > Sorry, I can't help but trolling here when checkpatch enforce obviously > disgusting and wasteful coding style. ... but not this. Most if not all code in my subsystem adheres to this rule, and I value consistency.
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index 284f8670dbeb..5dec00d663eb 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -12,6 +12,7 @@ #include <linux/clk.h> #include <linux/completion.h> +#include <linux/delay.h> #include <linux/err.h> #include <linux/errno.h> #include <linux/i2c.h> @@ -27,6 +28,7 @@ #include <linux/of_irq.h> #include <linux/of_platform.h> #include <linux/platform_device.h> +#include <linux/reset.h> #include <linux/slab.h> /* I2C Register */ @@ -132,6 +134,7 @@ struct aspeed_i2c_bus { struct i2c_adapter adap; struct device *dev; void __iomem *base; + struct reset_control *rst; /* Synchronizes I/O mem access to base. */ spinlock_t lock; struct completion cmd_complete; @@ -847,6 +850,13 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev) /* We just need the clock rate, we don't actually use the clk object. */ devm_clk_put(&pdev->dev, parent_clk); + bus->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); + if (IS_ERR(bus->rst)) { + dev_err(&pdev->dev, "invalid reset controller in device tree"); + bus->rst = NULL; + } else + reset_control_deassert(bus->rst); + ret = of_property_read_u32(pdev->dev.of_node, "bus-frequency", &bus->bus_frequency); if (ret < 0) { @@ -919,6 +929,8 @@ static int aspeed_i2c_remove_bus(struct platform_device *pdev) i2c_del_adapter(&bus->adap); + reset_control_assert(bus->rst); + return 0; }