Re: [PATCH 5/5] i8042: Add i8042_dt.h glue for DT support

[Roman Volkov]

Ð Tue, 3 Feb 2015 11:52:50 +0000
Mark Rutland <mark.rutland@xxxxxxx> ÐÐÑÐÑ:

> On Mon, Feb 02, 2015 at 09:48:50PM +0000, Roman Volkov wrote:
> > This header file designed to be similar to other glue layers found
> > for i8042. The difference is that interrupt numbers, device address,
> > and other information should be retrieved from the device tree.
> > 
> > Signed-off-by: Tony Prisk <linux@xxxxxxxxxxxxxxx>
> > Signed-off-by: Roman Volkov <v1ron@xxxxxxxxx>
> > ---
> >  drivers/input/serio/i8042-dt.h | 112
> > +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 112
> > insertions(+) create mode 100644 drivers/input/serio/i8042-dt.h
> > 
> > diff --git a/drivers/input/serio/i8042-dt.h
> > b/drivers/input/serio/i8042-dt.h new file mode 100644
> > index 0000000..0d1a344
> > --- /dev/null
> > +++ b/drivers/input/serio/i8042-dt.h
> > @@ -0,0 +1,112 @@
> > +#ifndef _I8042_DT_H
> > +#define _I8042_DT_H
> > +
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_irq.h>
> > +
> > +/*
> > + * This program is free software; you can redistribute it and/or
> > modify it
> > + * under the terms of the GNU General Public License version 2 as
> > published by
> > + * the Free Software Foundation.
> > + */
> > +
> > +static void __iomem *i8042_base;
> > +static unsigned int i8042_command_reg;
> > +static unsigned int i8042_status_reg;
> > +static unsigned int i8042_data_reg;
> > +#define I8042_COMMAND_REG i8042_command_reg
> > +#define I8042_STATUS_REG i8042_status_reg
> > +#define I8042_DATA_REG i8042_data_reg
> > +
> > +/*
> > + * Names.
> > + */
> > +
> > +static const char *i8042_kbd_phys_desc;
> > +static const char *i8042_aux_phys_desc;
> > +static const char *i8042_mux_phys_desc;
> > +#define I8042_KBD_PHYS_DESC i8042_kbd_phys_desc
> > +#define I8042_AUX_PHYS_DESC i8042_aux_phys_desc
> > +#define I8042_MUX_PHYS_DESC i8042_mux_phys_desc
> > +
> > +/*
> > + * IRQs.
> > + */
> > +static int i8042_kbd_irq;
> > +static int i8042_aux_irq;
> > +#define I8042_KBD_IRQ i8042_kbd_irq
> > +#define I8042_AUX_IRQ i8042_aux_irq
> 
> That's a lot of static values. Surely nothing physically prevents the
> use of multiple i8042 chips?
> 
> > +
> > +static inline int i8042_read_data(void)
> > +{
> > +	return readb(i8042_base + i8042_data_reg);
> > +}
> > +
> > +static inline int i8042_read_status(void)
> > +{
> > +	return readb(i8042_base + i8042_status_reg);
> > +}
> > +
> > +static inline void i8042_write_data(int val)
> > +{
> > +	writeb(val, i8042_base + i8042_data_reg);
> > +}
> > +
> > +static inline void i8042_write_command(int val)
> > +{
> > +	writeb(val, i8042_base + i8042_command_reg);
> > +}
> > +
> > +static inline int i8042_platform_init(struct platform_device *pdev)
> > +{
> > +	struct device_node *np = pdev->dev.of_node;
> > +	int status;
> > +
> > +	i8042_base = of_iomap(np, 0);
> > +	if (!i8042_base)
> > +		return -ENOMEM;
> > +
> > +	status = of_property_read_u32(np, "command-reg",
> > &i8042_command_reg);
> > +	if (status)
> > +		return status;
> > +
> > +	status = of_property_read_u32(np, "status-reg",
> > &i8042_status_reg);
> > +	if (status)
> > +		return status;
> > +
> > +	status = of_property_read_u32(np, "data-reg",
> > &i8042_data_reg);
> > +	if (status)
> > +		return status;
> 
> You should probably validate that these are within the range provided
> in the reg property.
> 
> You also need to clean up if you fail. It looks like here and below we
> leak the i8042_base mapping if we decide to fail.
> 
> > +
> > +	i8042_kbd_irq = irq_of_parse_and_map(np, 0);
> > +	i8042_aux_irq = irq_of_parse_and_map(np, 1);
> 
> You can use platform_get_irq(pdev, N) here, the IRQ will already have
> been parsed by the core.
> 
> > +	status = of_property_read_string(np, "linux,kbd_phys_desc",
> > +
> > &i8042_kbd_phys_desc);
> > +	if (status)
> > +		i8042_kbd_phys_desc = "i8042/serio0";
> > +
> > +	status = of_property_read_string(np, "linux,aux_phys_desc",
> > +
> > &i8042_aux_phys_desc);
> > +	if (status)
> > +		i8042_aux_phys_desc = "i8042/serio1";
> > +
> > +	status = of_property_read_string(np, "linux,mux_phys_desc",
> > +
> > &i8042_mux_phys_desc);
> > +	if (status)
> > +		i8042_mux_phys_desc = "i8042/serio%d";
> 
> User-provided values as format strings? Not a good idea.
> 
> What exactly are these used for?
> 
> > +
> > +	if (of_get_property(np, "init-reset", NULL))
> > +		i8042_reset = true;
> 
> Use of_property_read_bool.
> 
> Thanks,
> Mark.

Mark, thanks for the good review. The current i8042 driver likely does
not support multiple controllers. Maybe Dmitry will comment something
regarding this and overall idea.

I will check the case when DTS contains multiple i8042-compatible
nodes. Expected behavior is that only the first node will be parsed and
next nodes are silently ignored.

Regards,
Roman.

Regards,
Roman.
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