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Message-ID: <CAB=otbSpspZ9Z_fOpBvE1mPtt+JwZydZrgcR2LdkD_4CrGa_eg@mail.gmail.com>
Date: Wed, 13 Feb 2013 21:23:51 +0200
From: Ruslan Bilovol <ruslan.bilovol@...com>
To: Andi Shyti <andi@...zian.org>
Cc: tomi.valkeinen@...com, FlorianSchandinat@....de,
linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-omap@...r.kernel.org
Subject: Re: [PATCH v2 1/1] OMAP4: DSS: Add panel for Blaze Tablet boards
Hi Andi,
Thanks for your review,
On Mon, Feb 11, 2013 at 1:51 AM, Andi Shyti <andi@...zian.org> wrote:
> Hi Ruslan,
>
>> TC358765 is DSI-to-LVDS transmitter from Toshiba, used in
>> OMAP44XX Blaze Tablet and Blaze Tablet2 boards.
>
> I think it's fine, just some nitpicks and checkpatch warnings
>
>> +struct {
>> + struct device *dev;
>> + struct dentry *dir;
>> +} tc358765_debug;
>
> Should this be static?
Agree.
>
>> +struct tc358765_reg {
>> + const char *name;
>> + u16 reg;
>> + u8 perm:2;
>> +} tc358765_regs[] = {
>
> Should this be static as well?
Agree.
>
>> + { "D1S_ZERO", D1S_ZERO, A_RW },
>> + { "D2S_ZERO", D2S_ZERO, A_RW },
>> + { "D3S_ZERO", D3S_ZERO, A_RW },
>> + { "PPI_CLRFLG", PPI_CLRFLG, A_RW },
>> + { "PPI_CLRSIPO", PPI_CLRSIPO, A_RW },
>> + { "PPI_HSTimeout", PPI_HSTimeout, A_RW },
>
> WARNING: Avoid CamelCase: <PPI_HSTimeout>
> #136: FILE: video/omap2/displays/panel-tc358765.c:136:
> + { "PPI_HSTimeout", PPI_HSTimeout, A_RW },
>
>> + { "PPI_HSTimeoutEnable", PPI_HSTimeoutEnable, A_RW },
>
> WARNING: Avoid CamelCase: <PPI_HSTimeoutEnable>
> #137: FILE: video/omap2/displays/panel-tc358765.c:137:
> + { "PPI_HSTimeoutEnable", PPI_HSTimeoutEnable, A_RW },
Hmm... I though these registers had such naming in the documentation,
however, after looking into it I found the names are in upper case there
so this will be fixed.
>
>
>> +static int tc358765_read_block(u16 reg, u8 *data, int len)
>> +{
>> + unsigned char wb[2];
>> + struct i2c_msg msg[2];
>> + int r;
>> + mutex_lock(&tc358765_i2c->xfer_lock);
>> + wb[0] = (reg & 0xff00) >> 8;
>> + wb[1] = reg & 0xff;
>> + msg[0].addr = tc358765_i2c->client->addr;
>> + msg[0].len = 2;
>> + msg[0].flags = 0;
>> + msg[0].buf = wb;
>> + msg[1].addr = tc358765_i2c->client->addr;
>> + msg[1].flags = I2C_M_RD;
>> + msg[1].len = len;
>> + msg[1].buf = data;
>> +
>> + r = i2c_transfer(tc358765_i2c->client->adapter, msg, ARRAY_SIZE(msg));
>> + mutex_unlock(&tc358765_i2c->xfer_lock);
>> +
>> + if (r == ARRAY_SIZE(msg))
>> + return len;
>> +
>> + return r;
>
> If you like, here you could do
>
> return (r == ARRAY_SIZE(msg)) ? len : r;
>
> Usually I like more this notation because keeps the code more
> compact and immediate to read, but you don't have to
Yes, makes sense for "beautification" :)
Will change
>
>> + mutex_lock(&tc358765_i2c->xfer_lock);
>> + ret = i2c_transfer(tc358765_i2c->client->adapter, &msg, 1);
>> + mutex_unlock(&tc358765_i2c->xfer_lock);
>> +
>> + if (ret != 1)
>> + return ret;
>> + return 0;
>
> Also here you could do
>
> return (ret != 1) ? ret : 0;
>
> But this is more taste :)
>
>> +static ssize_t tc358765_seq_write(struct file *filp, const char __user *ubuf,
>> + size_t size, loff_t *ppos)
>> +{
>> + struct device *dev = tc358765_debug.dev;
>> + unsigned i, reg_count;
>> + u32 value = 0;
>> + int error = 0;
>> + /* kids, don't use register names that long */
>
> I won't, promised, but please, drop this comment :)
>
>> + char name[30];
>> + char buf[50];
>> +
>> + if (size >= sizeof(buf))
>> + size = sizeof(buf);
>
> what's the point of this?
This is a way to limit copied from userspace data by available buffer size,
widely used in current kernel sources. Are you implying there is some
better (more graceful) way?
>
>> +static void tc358765_uninitialize_debugfs(void)
>> +{
>> + if (tc358765_debug.dir)
>> + debugfs_remove_recursive(tc358765_debug.dir);
>
> WARNING: debugfs_remove_recursive(NULL) is safe this check is probably not required
> #435: FILE: video/omap2/displays/panel-tc358765.c:435:
> + if (tc358765_debug.dir)
> + debugfs_remove_recursive(tc358765_debug.dir);
Will fix it..
>
>
>> +static struct tc358765_board_data *get_board_data(struct omap_dss_device
>> + *dssdev)
>> +{
>> + return (struct tc358765_board_data *)dssdev->data;
>
> You shouldn't need for this cast, does it complain?
yes, we don't need this :)
>
>> +}
>> +
>> +static void tc358765_get_timings(struct omap_dss_device *dssdev,
>> + struct omap_video_timings *timings)
>> +{
>> + *timings = dssdev->panel.timings;
>> +}
>> +
>> +static void tc358765_set_timings(struct omap_dss_device *dssdev,
>> + struct omap_video_timings *timings)
>> +{
>> + dev_info(&dssdev->dev, "set_timings() not implemented\n");
>
> ... then drop the function :)
I need to check if this will have any side effects in places where
this is used. I mean next:
| if (blabla->set_timings)
| blabla->set_timings();
| else
| do_another_thing();
But it seems this may be safely removed
>
>> + if ((pins[2] & 1) || (pins[3] & 1)) {
>> + lanes |= (1 << 1);
>> + ret |= tc358765_write_register(dssdev, PPI_D0S_CLRSIPOCOUNT,
>> + board_data->clrsipo);
>> + }
>> + if ((pins[4] & 1) || (pins[5] & 1)) {
>> + lanes |= (1 << 2);
>> + ret |= tc358765_write_register(dssdev, PPI_D1S_CLRSIPOCOUNT,
>> + board_data->clrsipo);
>> + }
>> + if ((pins[6] & 1) || (pins[7] & 1)) {
>> + lanes |= (1 << 3);
>> + ret |= tc358765_write_register(dssdev, PPI_D2S_CLRSIPOCOUNT,
>> + board_data->clrsipo);
>> + }
>> + if ((pins[8] & 1) || (pins[9] & 1)) {
>> + lanes |= (1 << 4);
>> + ret |= tc358765_write_register(dssdev, PPI_D3S_CLRSIPOCOUNT,
>> + board_data->clrsipo);
>> + }
>
> Can't this be done in one single multiwrighting command since
> this registers are consecutive?
>
> You build once the array to write and you send it at once.
In this particular case I disagree. Yes, it will be a little bit
faster, however:
1) we write this for panel initialization only (so no impact in other cases)
2) multiwriting of array will make code reading more difficult
So I would like to leave it as-is
Same is for next your similar comment.
>
> Moreover it would be nice to have a name for all those nombers
Okay, will replace magic numbers by defined values
>
>> + ret |= tc358765_write_register(dssdev, HTIM1,
>> + (tc358765_timings.hbp << 16) | tc358765_timings.hsw);
>> + ret |= tc358765_write_register(dssdev, HTIM2,
>> + ((tc358765_timings.hfp << 16) | tc358765_timings.x_res));
>> + ret |= tc358765_write_register(dssdev, VTIM1,
>> + ((tc358765_timings.vbp << 16) | tc358765_timings.vsw));
>> + ret |= tc358765_write_register(dssdev, VTIM2,
>> + ((tc358765_timings.vfp << 16) | tc358765_timings.y_res));
>
> also this and all the other cases I haven't checked
>
>> +static int tc358765_enable(struct omap_dss_device *dssdev)
>> +{
>> + struct tc358765_data *d2d = dev_get_drvdata(&dssdev->dev);
>> + int r = 0;
>
> this initialisation is useless
Agree
>
>> + if (r) {
>> + dev_dbg(&dssdev->dev, "enable failed\n");
>
> Here you could choose a different print level, I would have used
> dev_err instead.
Agree
>
>> +static int tc358765_i2c_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + tc358765_i2c = devm_kzalloc(&client->dev, sizeof(*tc358765_i2c), GFP_KERNEL);
>
> WARNING: line over 80 characters
> #927: FILE: video/omap2/displays/panel-tc358765.c:927:
> + tc358765_i2c = devm_kzalloc(&client->dev, sizeof(*tc358765_i2c), GFP_KERNEL);
Agree :)
>
>
>> + /* store i2c_client pointer on private data structure */
>> + tc358765_i2c->client = client;
>> +
>> + /* store private data structure pointer on i2c_client structure */
>> + i2c_set_clientdata(client, tc358765_i2c);
>> +
>> + /* init mutex */
>> + mutex_init(&tc358765_i2c->xfer_lock);
>> + dev_err(&client->dev, "D2L i2c initialized\n");
>
> while here dev_dbg (or dev_info) are better.
Agree
>
>> +static int __init tc358765_init(void)
>> +{
>> + int r;
>> + tc358765_i2c = NULL;
>> + r = i2c_add_driver(&tc358765_i2c_driver);
>> + if (r < 0) {
>> + printk(KERN_WARNING "d2l i2c driver registration failed\n");
>
> WARNING: Prefer netdev_warn(netdev, ... then dev_warn(dev, ... then pr_warn(... to printk(KERN_WARNING ...
> #981: FILE: video/omap2/displays/panel-tc358765.c:981:
> + printk(KERN_WARNING "d2l i2c driver registration failed\n");
Agree
--
Best regards,
Ruslan
>
>
> Andi
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