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Date: Sun, 6 Mar 2016 14:00:38 +0100
From: Jan Glauber <jan.glauber@...iumnetworks.com>
To: Wolfram Sang <wsa@...-dreams.de>
CC: <linux-kernel@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
David Daney <ddaney@...iumnetworks.com>
Subject: Re: [PATCH v2 01/10] i2c-octeon: Cleanup i2c-octeon driver
On Sat, Mar 05, 2016 at 07:47:31PM +0100, Wolfram Sang wrote:
> Hi Jan,
>
> The description is not enough. A list what kind of changes you applied
> would be nice.
OK.
> I'd like to have these checkpatch issues fixed:
>
> ERROR: trailing statements should be on next line
> #177: FILE: drivers/i2c/busses/i2c-octeon.c:133:
> + while ((tmp & SW_TWSI_V) != 0);
>
> ERROR: trailing statements should be on next line
> #202: FILE: drivers/i2c/busses/i2c-octeon.c:152:
> + while ((tmp & SW_TWSI_V) != 0);
Fixed. Strange that checkpatch.pl -f (use on file) does not report these
errors though.
> CHECK: Prefer using the BIT_ULL macro
> #52: FILE: drivers/i2c/busses/i2c-octeon.c:39:
> +#define SW_TWSI_V (1ULL << 63)
OK
> Note: I don't care so much about the 80 char limit as long as the line
> length is not too excessive.
Fine, same opinion here. I'll try to limit the 80 char changes to a
sane minimum then.
>
> > -#define DRV_NAME "i2c-octeon"
> > +#define DRV_NAME "i2c-octeon"
>
> I'm in favor for indenting register and bit defines, but other than that
> I think one space is enough. I won't force my opinion on you, though.
> Just wanted to let you know.
OK
> > +#define INT_ENA_ST 0x1
> > +#define INT_ENA_TS 0x2
> > +#define INT_ENA_CORE 0x4
>
> I assume those are bits? Then, they shouldn't be in the registers
> section.
I'll move them to the thunderx patch.
> > +/* TWSI_INT values */
> > +#define ST_INT 0x01
> > +#define TS_INT 0x02
> > +#define CORE_INT 0x04
> > +#define ST_EN 0x10
> > +#define TS_EN 0x20
> > +#define CORE_EN 0x40
> > +#define SDA_OVR 0x100
> > +#define SCL_OVR 0x200
> > +#define SDA 0x400
> > +#define SCL 0x800
>
> I think those should have a prefix. SDA and SCL are dangerously generic.
Agreed, I'll make these TWSI_INT_*.
> > struct octeon_i2c {
> > - wait_queue_head_t queue;
> > - struct i2c_adapter adap;
> > - int irq;
> > - u32 twsi_freq;
> > - int sys_freq;
> > - resource_size_t twsi_phys;
> > - void __iomem *twsi_base;
> > - resource_size_t regsize;
> > - struct device *dev;
> > + wait_queue_head_t queue;
> > + struct i2c_adapter adap;
> > + int irq;
> > + u32 twsi_freq;
> > + int sys_freq;
> > + void __iomem *twsi_base;
> > + struct device *dev;
>
> NAK. structs change often, and then one needs to fix the whole
> indentation. One space is enough here.
Not sure I understand your argument. I find this form more readable
but I can change that to one space.
> > };
>
> > -static u8 octeon_i2c_read_sw(struct octeon_i2c *i2c, u64 eop_reg)
> > +static u64 octeon_i2c_read_sw64(struct octeon_i2c *i2c, u64 eop_reg)
> ...
> > - return tmp & 0xFF;
> > + return tmp;
> > +}
> ...
> > +
> > +/**
> > + * octeon_i2c_read_sw - read lower bits of an I2C core register
> > + * @i2c: The struct octeon_i2c
> > + * @eop_reg: Register selector
> > + *
> > + * Returns the data.
> > + *
> > + * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
> > + */
> > +static u8 octeon_i2c_read_sw(struct octeon_i2c *i2c, u64 eop_reg)
> > +{
> > + return octeon_i2c_read_sw64(i2c, eop_reg);
> > }
>
> This is not a cleanup!
OK, I'll move that to the patch where it's used.
> > +/* disable the CORE interrupt */
> > static void octeon_i2c_int_disable(struct octeon_i2c *i2c)
> > {
> > - octeon_i2c_write_int(i2c, 0);
> > + /* clear TS/ST/IFLG events */
> > + octeon_i2c_write_int(i2c, TS_INT | ST_INT);
> > }
>
> Isn't this a functional change?
Looks like a bug, I'll drop that.
> > /**
> > - * octeon_i2c_unblock - unblock the bus.
> > - * @i2c: The struct octeon_i2c.
> > + * bitbang_unblock - unblock the bus
> > + * @i2c: The struct octeon_i2c
> > *
> > - * If there was a reset while a device was driving 0 to bus,
> > - * bus is blocked. We toggle it free manually by some clock
> > - * cycles and send a stop.
> > + * If there was a reset while a device was driving 0 to bus, bus is blocked.
> > + * We toggle it free manually by some clock cycles and send a stop.
> > */
> > -static void octeon_i2c_unblock(struct octeon_i2c *i2c)
> > +static void bitbang_unblock(struct octeon_i2c *i2c)
>
> I dunno understand the change of the function name. However, this should
> be refactored to use the i2c_bus_recovery infrastructure anyhow.
I'll leave the function name as it is. Would it be possbile to address
the refactoring in a follow-up patch after this series is finished?
> > - result = wait_event_timeout(i2c->queue,
> > - octeon_i2c_test_iflg(i2c),
> > - i2c->adap.timeout);
> > -
> > + result = wait_event_timeout(i2c->queue, octeon_i2c_test_iflg(i2c),
> > + i2c->adap.timeout);
>
> You could rename this variable to 'time_left' to make the code even
> easier to read.
Agreed.
> > static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
> > - const u8 *data, int length)
> > + u8 *data, int length)
>
> Why this change?
>
> > {
> > - int i, result;
> > + int result, i;
>
> And this?
I'll drop these two, just noise from merging back and forth.
> > -static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
> > - u8 *data, int length)
> > +static int octeon_i2c_read(struct octeon_i2c *i2c, int target, u8 *data,
> > + u16 *rlength)
> > {
> > + int length = *rlength;
>
> And this?
I'll move this to the patch where it's used.
> > @@ -353,15 +411,14 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
> > if (result)
> > return result;
> >
> > - octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, (target<<1) | 1);
> > - octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
> > -
> > + octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, TWSI_CTL_ENAB);
>
> Is this really the same?
I'll move this to a later patch.
> > static u32 octeon_i2c_functionality(struct i2c_adapter *adap)
> > @@ -435,13 +490,10 @@ static struct i2c_adapter octeon_i2c_ops = {
> > .owner = THIS_MODULE,
> > .name = "OCTEON adapter",
> > .algo = &octeon_i2c_algo,
> > - .timeout = HZ / 50,
>
> This is a functional change, or?
Hmm, it isn't for arm64 (HZ 250) but it would be for MIPS (HZ 100). I'll make it
a seperate patch then.
> > - i2c->twsi_phys = res_mem->start;
> > - i2c->regsize = resource_size(res_mem);
>
> Those are removed which is okay in general, but should be in a seperate
> patch.
OK
> This patch was hard to review because so many changes were overlapping.
> It really should have been broken out. Like one patch only removing the
> trailing "." in the kernel-doc. One fixing the indentation issues. One
> removing the now superfluous fields in struct octeon_i2c, etc...
I'll split it into several patches then.
Thanks for reviewing,
Jan
> Wolfram
>
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