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Date: Fri, 8 Feb 2013 14:30:17 +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 1/1] OMAP4: DSS: Add panel for Blaze Tablet boards
Hi,
Thanks for looking into
On Thu, Feb 7, 2013 at 4:59 PM, Andi Shyti <andi@...zian.org> wrote:
> Hi,
>
>> TC358765 is DSI-to-LVDS transmitter from Toshiba, used in
>> OMAP44XX Blaze Tablet and Blaze Tablet2 boards.
>
> I had a really fast look and I have few comments
>
>> +static int tc358765_read_register(struct omap_dss_device *dssdev,
>> + u16 reg, u32 *val)
>> +{
>> + int ret = 0;
>> + pm_runtime_get_sync(&dssdev->dev);
>> + /* I2C is preferred way of reading, but fall back to DSI
>> + * if I2C didn't got initialized
>> + */
>> + if (tc358765_i2c)
>> + ret = tc358765_i2c_read(reg, val);
>> + else
>> + ret = tc358765_dsi_read(dssdev, reg, val);
>> + pm_runtime_put_sync(&dssdev->dev);
>> +
>> + return ret;
>> +}
>> +
>> +static int tc358765_write_register(struct omap_dss_device *dssdev, u16 reg,
>> + u32 value)
>> +{
>> + struct tc358765_data *d2d = dev_get_drvdata(&dssdev->dev);
>> + u8 buf[6];
>> + int r;
>> +
>> + buf[0] = (reg >> 0) & 0xff;
>> + buf[1] = (reg >> 8) & 0xff;
>> + buf[2] = (value >> 0) & 0xff;
>> + buf[3] = (value >> 8) & 0xff;
>> + buf[4] = (value >> 16) & 0xff;
>> + buf[5] = (value >> 24) & 0xff;
>> +
>> + r = dsi_vc_generic_write_nosync(dssdev, d2d->channel1, buf, 6);
>> + if (r)
>> + dev_err(&dssdev->dev, "reg write reg(%x) val(%x) failed: %d\n",
>> + reg, value, r);
>> + return r;
>> +}
>> +
>> +/****************************
>> +********* DEBUG *************
>> +****************************/
>> +#ifdef CONFIG_TC358765_DEBUG
>> +static int tc358765_write_register_i2c(u16 reg, u32 val)
>> +{
>> + int ret = -ENODEV;
>> + unsigned char buf[6];
>> + struct i2c_msg msg;
>> +
>> + if (!tc358765_i2c) {
>> + dev_err(tc358765_debug.dev, "%s: I2C not initilized\n",
>> + __func__);
>> + return ret;
>> + }
>> +
>> + buf[0] = (reg >> 8) & 0xff;
>> + buf[1] = (reg >> 0) & 0xff;
>> + buf[2] = (val >> 0) & 0xff;
>> + buf[3] = (val >> 8) & 0xff;
>> + buf[4] = (val >> 16) & 0xff;
>> + buf[5] = (val >> 24) & 0xff;
>> + msg.addr = tc358765_i2c->client->addr;
>> + msg.len = sizeof(buf);
>> + msg.flags = 0;
>> + msg.buf = buf;
>> +
>> + 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;
>> +}
>
> What about using smbus?
OMAP2+ SoCs have full I2C controller so panel drivers traditionally use I2C.
Since implementation is OMAP-specific, I don't think we need to use smbus here.
Also please look at other panels implementation:
drivers/video/omap2/displays/panel-tfp410.c
drivers/video/omap2/displays/panel-picodlp.c
>
>> +
>> + if (copy_from_user(&buf, ubuf, size))
>> + return -EFAULT;
>> +
>> + buf[size-1] = '\0';
>> + if (sscanf(buf, "%s %x", name, &value) != 2) {
>> + dev_err(dev, "%s: unable to parse input\n", __func__);
>> + return -1;
>> + }
>> +
>> + if (!tc358765_i2c) {
>> + dev_warn(dev,
>> + "failed to write register: I2C not initialized\n");
>> + return -ENODEV;
>> + }
>> +
>> + reg_count = sizeof(tc358765_regs) / sizeof(tc358765_regs[0]);
>> + for (i = 0; i < reg_count; i++) {
>> + if (!strcmp(name, tc358765_regs[i].name)) {
>> + if (!(tc358765_regs[i].perm & A_WO)) {
>> + dev_err(dev, "%s is write-protected\n", name);
>> + return -EACCES;
>> + }
>> +
>> + error = tc358765_write_register_i2c(
>> + tc358765_regs[i].reg, value);
>> + if (error) {
>> + dev_err(dev, "%s: failed to write %s\n",
>> + __func__, name);
>> + return -1;
>
> Could avoid returning -1 instead of returning a correct errno?
Agree. Will be fixed in next patchset
>
>> + gpio_set_value(dssdev->reset_gpio, 1);
>> + udelay(200);
>> + /* reset the panel */
>> + gpio_set_value(dssdev->reset_gpio, 0);
>> + /* assert reset */
>> + udelay(200);
>> + gpio_set_value(dssdev->reset_gpio, 1);
>> + /* wait after releasing reset */
>> + msleep(200);
>
> I invite you to have a look at
>
> Documentation/timers/timers-howto.txt
Will be fixed in next patchset
>
>> + /* reset LVDS-PHY */
>> + tc358765_write_register(dssdev, LVPHY0, (1 << 22));
>> + mdelay(2);
>
> You should give me a really good reason for using mdelay.
Will be fixed in next patchset
>
>> + if (r) {
>> + dev_err(&dssdev->dev, "failed to configure DSI pins\n");
>> + goto err_disp_enable;
>> + };
> ^^^
>
> ???
Just a typo. Will be fixed in next patchset
>
>> +static int tc358765_i2c_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + tc358765_i2c = kzalloc(sizeof(*tc358765_i2c), GFP_KERNEL);
>
> what about devm_kzalloc?
Will be fixed in next patchset
-
Ruslan
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