> -----Original Message-----
> From: Valkeinen, Tomi
> Sent: Tuesday, May 10, 2011 3:03 PM
> To: Janorkar, Mayuresh
> Cc: linux-omap@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 4/4] OMAP: DSS: Add picodlp panel driver
>
> On Mon, 2011-05-09 at 20:48 +0530, Mayuresh Janorkar wrote:
> >
<snip>
> > +/* This defines the minit of data which is allowed into single write
> block */
> > +#define MAX_I2C_WRITE_BLOCK_SIZE 32
> > +#define PICO_MAJOR 1 /* 2 bits */
> > +#define PICO_MINOR 1 /* 2 bits */
> > +#define MAX_TRIAL_VALUE 50
>
> The name of this define is not descriptive and you use this define in
> two places which have nothing to do with each other. I think it's better
> just to use the value where it's needed.
Looks fine.
>
> > +struct picodlp_data {
> > + struct mutex lock;
> > + struct i2c_client *picodlp_i2c_client;
> > +};
> > +
> > +static struct i2c_board_info picodlp_i2c_board_info = {
> > + I2C_BOARD_INFO("picodlp_i2c_driver", 0x1b),
> > +};
> > + r = i2c_transfer(client->adapter, &msg, msg_count);
> > + mutex_unlock(&picodlp_i2c_data->xfer_lock);
> > +
> > + /*
> > + * i2c_transfer returns:
> > + * number of messages sent in case of success
> > + * a negative error number in case of failure
> > + * i2c controller might timeout, in such a case sleep for sometime
> > + * and then retry
> > + */
>
> The comment here doesn't look right, there's no retry.
Fine.
>
> > + if (r != msg_count)
> > + goto err;
> > +
> > + /* In case of success */
> > + for (i = 0; i < len; i++)
> > + dev_dbg(&client->dev,
> > + {SEQ_CONTROL, 1}
> > + };
> > +
> > + msleep(510);
>
> You are again sleeping in a place where there are no clear actions after
> and before the sleep. You should always sleep between two well defined
> actions. In this case it's the emu_done going up and the first i2c
> transaction, so a better place for this sleep is in the power_on
> function, before calling this function. With a comment saying what we
> are waiting for.
I would move this to power_on function with an appropriate comment.
>
> > + r = picodlp_i2c_write_array(client, init_cmd_set1,
> > + ARRAY_SIZE(init_cmd_set1));
> > + if (r)
> > + return r;
> > + msleep(5);
> > + }
>
> You defined the trial value to 50, which means this could timeout after
> 250ms. If I remember right, it could take 500ms until emu_done changes.
> And your error says "going down", doesn't the emu_done gpio go up when
> it's ready?
Looks fine. I would change the counter.
My bad. I meant to say emu_done is still down.
>
> > +
> > + r = omapdss_dpi_display_enable(dssdev);
> > + if (r) {
> > + dev_err(&dssdev->dev, "failed to enable DPI\n");
> > + goto err;
> > +static void picodlp_panel_power_off(struct omap_dss_device *dssdev)
> > +{
> > + struct picodlp_panel_data *picodlp_pdata = get_panel_data(dssdev);
> > +
> > + omapdss_dpi_display_disable(dssdev);
> > +
> > + gpio_set_value(picodlp_pdata->emu_done_gpio, 0);
>
> emu_done is an input pin, you can't set its value.
Yes.
>
> > + gpio_set_value(picodlp_pdata->pwrgood_gpio, 0);
> > +
> > + if (dssdev->platform_disable)
> > + dssdev->platform_disable(dssdev);
> > +}
> > +
> > +static int picodlp_panel_probe(struct omap_dss_device *dssdev)
> > +{
> > + struct picodlp_data *picod;
> > + struct picodlp_panel_data *picodlp_pdata = get_panel_data(dssdev);
> > + struct i2c_adapter *adapter;
> > + struct i2c_client *picodlp_i2c_client;
> > + struct picodlp_i2c_data *picodlp_i2c_data;
> > + struct gpio picodlp_gpios[] = {
> > + {picodlp_pdata->emu_done_gpio, GPIOF_IN, "DLP EMU DONE"},
> > + {picodlp_pdata->pwrgood_gpio, GPIOF_INIT_LOW, "DLP PWRGOOD"},
> > + };
>
> pwrgood_gpio should be GPIOF_OUT_INIT_LOW.
Looks fine
>
> It is better to request and initialize the GPIOs in the board file. The
> reason for this is that the PicoDLP device should be off if it's not
> used, or if the driver is not even compiled in. So the board file should
> make sure that the GPIOs are in such state that the device is off.
The board file has only init. There is no exit.
So if I request gpios in init once, I could not find a place to free them.
Is it a good idea to request gpios in platform_enable and free them in platform_disable?
>
> > +
> > + int r = 0, picodlp_adapter_id;
> > +
> > + dssdev->panel.config = OMAP_DSS_LCD_TFT | OMAP_DSS_LCD_ONOFF |
> > + OMAP_DSS_LCD_IHS | OMAP_DSS_LCD_IVS;
> > + r = -ENODEV;
> > + goto err;
> > + }
> > +
> > + picod->picodlp_i2c_client = picodlp_i2c_client;
> > +
> > + picodlp_i2c_data =
> > + i2c_get_clientdata(picod->picodlp_i2c_client);
> > +
> > + mutex_init(&picodlp_i2c_data->xfer_lock);
>
> I don't think this is right. You have no guarantees that the i2c device
> probe would have been called when the execution reaches here. So
> picodlp_i2c_data could be NULL.
I would add a check for this.
>
> And anyway, why would you initialize the mutex here, as the mutex
> belongs to the i2c side. The i2c probe would be more logical choice in
> any case.
I will move this to i2c_probe.
>
> Tomi
>
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