Re: [PATCH 4/7] OMAP: DSS: Add i2c client driver for picodlp

Tomi Valkeinen
2011-04-19T11:27:04Z

On Mon, 2011-04-18 at 11:45 +0530, Mayuresh Janorkar wrote:
> The configurations and data transfer with picodlp panel happens through i2c.
> An i2c client with name "picodlp_i2c_driver" is registered inside panel.
>
> Signed-off-by: Mythri P K <mythripk@ti.com>
> Signed-off-by: Mayuresh Janorkar <mayur@ti.com>
> Signed-off-by: Mythri P K <mythripk@ti.com>
> ---
> drivers/video/omap2/displays/panel-picodlp.c | 130 +++++++++++++++++++++++++-
> 1 files changed, 126 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/video/omap2/displays/panel-picodlp.c b/drivers/video/omap2/displays/panel-picodlp.c
> index 4f12903..e361674 100644
> --- a/drivers/video/omap2/displays/panel-picodlp.c
> +++ b/drivers/video/omap2/displays/panel-picodlp.c
> @@ -1,8 +1,10 @@
> /*
> * picodlp panel driver
> + * picodlp_i2c_driver: i2c_client driver
> *
> * Copyright (C) 2009-2011 Texas Instruments
> * Author: Mythri P K <mythripk@ti.com>
> + * Mayuresh Janorkar <mayur@ti.com>
> *
> * 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
> @@ -23,13 +25,29 @@
> #include <linux/firmware.h>
> #include <linux/slab.h>
> #include <linux/mutex.h>
> +#include <linux/i2c.h>
> #include <linux/delay.h>
> +#include <linux/gpio.h>
>
> #include <plat/display.h>
> #include <plat/panel-picodlp.h>
>
> +#define DRIVER_NAME "picodlp_i2c_driver"
> 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),
> +};

Can this be const?

> +struct picodlp_i2c_data {
> + struct mutex xfer_lock;
> +};
> +
> +struct i2c_device_id picodlp_i2c_id[] = {
> + { "picodlp_i2c_driver", 0 },
> };

This should be static. Probably also const.

> static struct omap_video_timings pico_ls_timings = {
> @@ -46,9 +64,57 @@ static struct omap_video_timings pico_ls_timings = {
> .vbp = 14,
> };
>
> +static inline struct picodlp_panel_data
> + *get_panel_data(const struct omap_dss_device *dssdev)
> +{
> + return (struct picodlp_panel_data *) dssdev->data;
> +}
> +
> +static int picodlp_i2c_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct picodlp_i2c_data *picodlp_i2c_data;
> +
> + picodlp_i2c_data = kzalloc(sizeof(struct picodlp_i2c_data), GFP_KERNEL);
> +
> + if (!picodlp_i2c_data)
> + return -ENOMEM;
> +
> + i2c_set_clientdata(client, picodlp_i2c_data);
> +
> + return 0;
> +}
> +
> +static int picodlp_i2c_remove(struct i2c_client *client)
> +{
> + struct picodlp_i2c_data *picodlp_i2c_data =
> + i2c_get_clientdata(client);
> +
> + kfree(picodlp_i2c_data);
> + i2c_unregister_device(client);
> + return 0;
> +}
> +
> +static struct i2c_driver picodlp_i2c_driver = {
> + .driver = {
> + .name = "picodlp_i2c_driver",
> + },
> + .probe = picodlp_i2c_probe,
> + .remove = picodlp_i2c_remove,
> + .id_table = picodlp_i2c_id,
> +};
> +
> static int picodlp_panel_power_on(struct omap_dss_device *dssdev)
> {
> - int r;
> + int r = 0;
> + struct picodlp_data *picod = dev_get_drvdata(&dssdev->dev);
> + struct picodlp_panel_data *picodlp_pdata;
> + struct picodlp_i2c_data *picodlp_i2c_data;

Local variables don't need to be very long. The reader knows this is
pico dlp driver, so prepending the variable names with "picodlp_" is
quite extra and only make the code more difficult to read.

> + picodlp_pdata = get_panel_data(dssdev);
> + gpio_set_value(picodlp_pdata->display_sel_gpio, 1);
> + gpio_set_value(picodlp_pdata->park_gpio, 1);
> + gpio_set_value(picodlp_pdata->phy_reset_gpio, 1);

Are these GIOs related to i2c? I can't find these from the DLP
documents, at least with these names.

> if (dssdev->platform_enable) {
> r = dssdev->platform_enable(dssdev);
> @@ -65,8 +131,10 @@ static int picodlp_panel_power_on(struct omap_dss_device *dssdev)
> msleep(675);
> dssdev->state = OMAP_DSS_DISPLAY_ACTIVE;
>
> - return 0;
> + picodlp_i2c_data =
> + i2c_get_clientdata(picod->picodlp_i2c_client);
>
> + return r;
> err:
> if (dssdev->platform_disable)
> dssdev->platform_disable(dssdev);
> @@ -85,6 +153,11 @@ static void picodlp_panel_power_off(struct omap_dss_device *dssdev)
> static int picodlp_panel_probe(struct omap_dss_device *dssdev)
> {
> struct picodlp_data *picod;
> + struct picodlp_panel_data *picodlp_pdata;
> + struct i2c_adapter *adapter;
> + struct i2c_client *picodlp_i2c_client;
> + struct picodlp_i2c_data *picodlp_i2c_data;
> + 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;
> @@ -96,8 +169,38 @@ static int picodlp_panel_probe(struct omap_dss_device *dssdev)
> return -ENOMEM;
>
> mutex_init(&picod->lock);
> +
> + picodlp_pdata = get_panel_data(dssdev);
> + picodlp_adapter_id = picodlp_pdata->picodlp_adapter_id;
> +
> + adapter = i2c_get_adapter(picodlp_adapter_id);
> + if (!adapter) {
> + dev_err(&dssdev->dev, "can't get i2c adapter\n");
> + r = -ENODEV;
> + goto err;
> + }
> +
> + picodlp_i2c_client = i2c_new_device(adapter, &picodlp_i2c_board_info);
> + /* wait till i2c device creation is done */
> + msleep(700);

What is this sleep for? I'm quite sure the device is already created
when i2c_new_device() returns.

Tomi