media: em28xx: constify most static structs

There are several em28xx static structs that can now be constified.

That caused a significant reduction at data segment:

Before:
   text	   data	    bss	    dec	    hex	filename
  85017	  59588	    576	 145181	  2371d	drivers/media/usb/em28xx/em28xx.o

After:
   text	   data	    bss	    dec	    hex	filename
 112345	  32292	    576	 145213	  2373d	drivers/media/usb/em28xx/em28xx.o
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/em28xx/em28xx-core.c

@@ -712,7 +712,7 @@ int em28xx_capture_start(struct em28xx *dev, int start)
 	return rc;
 }
 
-int em28xx_gpio_set(struct em28xx *dev, struct em28xx_reg_seq *gpio)
+int em28xx_gpio_set(struct em28xx *dev, const struct em28xx_reg_seq *gpio)
 {
 	int rc = 0;
 

drivers/media/usb/em28xx/em28xx-input.c

@@ -515,7 +515,8 @@ static void em28xx_query_buttons(struct work_struct *work)
 		j = 0;
 		while (dev->board.buttons[j].role >= 0 &&
 		       dev->board.buttons[j].role < EM28XX_NUM_BUTTON_ROLES) {
-			struct em28xx_button *button = &dev->board.buttons[j];
+			const struct em28xx_button *button = &dev->board.buttons[j];
+
 			/* Check if button uses the current address */
 			if (button->reg_r != dev->button_polling_addresses[i]) {
 				j++;
@@ -618,7 +619,8 @@ static void em28xx_init_buttons(struct em28xx *dev)
 	dev->button_polling_interval = EM28XX_BUTTONS_DEBOUNCED_QUERY_INTERVAL;
 	while (dev->board.buttons[i].role >= 0 &&
 	       dev->board.buttons[i].role < EM28XX_NUM_BUTTON_ROLES) {
-		struct em28xx_button *button = &dev->board.buttons[i];
+		const struct em28xx_button *button = &dev->board.buttons[i];
+
 		/* Check if polling address is already on the list */
 		addr_new = true;
 		for (j = 0; j < dev->num_button_polling_addresses; j++) {

drivers/media/usb/em28xx/em28xx.h

@@ -386,7 +386,7 @@ struct em28xx_input {
 	unsigned int vmux;
 	enum em28xx_amux amux;
 	enum em28xx_aout aout;
-	struct em28xx_reg_seq *gpio;
+	const struct em28xx_reg_seq *gpio;
 };
 
 #define INPUT(nr) (&em28xx_boards[dev->model].input[nr])
@@ -450,10 +450,10 @@ struct em28xx_board {
 	unsigned int tda9887_conf;
 
 	/* GPIO sequences */
-	struct em28xx_reg_seq *dvb_gpio;
-	struct em28xx_reg_seq *suspend_gpio;
-	struct em28xx_reg_seq *tuner_gpio;
-	struct em28xx_reg_seq *mute_gpio;
+	const struct em28xx_reg_seq *dvb_gpio;
+	const struct em28xx_reg_seq *suspend_gpio;
+	const struct em28xx_reg_seq *tuner_gpio;
+	const struct em28xx_reg_seq *mute_gpio;
 
 	unsigned int is_em2800:1;
 	unsigned int has_msp34xx:1;
@@ -480,7 +480,7 @@ struct em28xx_board {
 	struct em28xx_led	  *leds;
 
 	/* Buttons */
-	struct em28xx_button	  *buttons;
+	const struct em28xx_button *buttons;
 };
 
 struct em28xx_eeprom {
@@ -792,7 +792,7 @@ int em28xx_init_usb_xfer(struct em28xx *dev, enum em28xx_mode mode,
 void em28xx_uninit_usb_xfer(struct em28xx *dev, enum em28xx_mode mode);
 void em28xx_stop_urbs(struct em28xx *dev);
 int em28xx_set_mode(struct em28xx *dev, enum em28xx_mode set_mode);
-int em28xx_gpio_set(struct em28xx *dev, struct em28xx_reg_seq *gpio);
+int em28xx_gpio_set(struct em28xx *dev, const struct em28xx_reg_seq *gpio);
 int em28xx_register_extension(struct em28xx_ops *dev);
 void em28xx_unregister_extension(struct em28xx_ops *dev);
 void em28xx_init_extension(struct em28xx *dev);
@@ -801,7 +801,7 @@ int em28xx_suspend_extension(struct em28xx *dev);
 int em28xx_resume_extension(struct em28xx *dev);
 
 /* Provided by em28xx-cards.c */
-extern struct em28xx_board em28xx_boards[];
+extern const struct em28xx_board em28xx_boards[];
 extern struct usb_device_id em28xx_id_table[];
 int em28xx_tuner_callback(void *ptr, int component, int command, int arg);
 void em28xx_setup_xc3028(struct em28xx *dev, struct xc2028_ctrl *ctl);