net/libertas: remove GPIO-CS handling in SPI interface code

This removes the dependency on GPIO framework and lets the SPI host
driver handle the chip select. The SPI host driver is required to keep
the CS active for the entire message unless cs_change says otherwise.
This patch collects the two/three single SPI transfers into a message.
Also the delay in read path in case use_dummy_writes are not used is
moved into the SPI host driver.

Tested-by: Mike Rapoport <[e-mail]>
Tested-by: Andrey Yurovsky <[e-mail]>
Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Acked-by: Dan Williams <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

drivers/net/wireless/Kconfig

···
 
 config LIBERTAS_SPI
 	tristate "Marvell Libertas 8686 SPI 802.11b/g cards"
-	depends on LIBERTAS && SPI && GENERIC_GPIO
+	depends on LIBERTAS && SPI
 	---help---
 	  A driver for Marvell Libertas 8686 SPI devices.
 

drivers/net/wireless/libertas/if_spi.c

···
 
 #include <linux/moduleparam.h>
 #include <linux/firmware.h>
-#include <linux/gpio.h>
 #include <linux/jiffies.h>
 #include <linux/kthread.h>
 #include <linux/list.h>
···
 	/* The card ID and card revision, as reported by the hardware. */
 	u16				card_id;
 	u8				card_rev;
-
-	/* Pin number for our GPIO chip-select. */
-	/* TODO: Once the generic SPI layer has some additional features, we
-	 * should take this out and use the normal chip select here.
-	 * We need support for chip select delays, and not dropping chipselect
-	 * after each word. */
-	int				gpio_cs;
 
 	/* The last time that we initiated an SPU operation */
 	unsigned long			prev_xfer_time;
···
 		 * If not, we have to busy-wait to be on the safe side. */
 		ndelay(400);
 	}
-	gpio_set_value(card->gpio_cs, 0); /* assert CS */
 }
 
 static void spu_transaction_finish(struct if_spi_card *card)
 {
-	gpio_set_value(card->gpio_cs, 1); /* drop CS */
 	card->prev_xfer_time = jiffies;
 }
 
···
 {
 	int err = 0;
 	u16 reg_out = cpu_to_le16(reg | IF_SPI_WRITE_OPERATION_MASK);
+	struct spi_message m;
+	struct spi_transfer reg_trans;
+	struct spi_transfer data_trans;
+
+	spi_message_init(&m);
+	memset(&reg_trans, 0, sizeof(reg_trans));
+	memset(&data_trans, 0, sizeof(data_trans));
 
 	/* You must give an even number of bytes to the SPU, even if it
 	 * doesn't care about the last one.  */
···
 	spu_transaction_init(card);
 
 	/* write SPU register index */
-	err = spi_write(card->spi, (u8 *)&reg_out, sizeof(u16));
-	if (err)
-		goto out;
+	reg_trans.tx_buf = &reg_out;
+	reg_trans.len = sizeof(reg_out);
 
-	err = spi_write(card->spi, buf, len);
+	data_trans.tx_buf = buf;
+	data_trans.len = len;
 
-out:
+	spi_message_add_tail(&reg_trans, &m);
+	spi_message_add_tail(&data_trans, &m);
+
+	err = spi_sync(card->spi, &m);
 	spu_transaction_finish(card);
 	return err;
 }
···
 
 static int spu_read(struct if_spi_card *card, u16 reg, u8 *buf, int len)
 {
-	unsigned int i, delay;
+	unsigned int delay;
 	int err = 0;
-	u16 zero = 0;
 	u16 reg_out = cpu_to_le16(reg | IF_SPI_READ_OPERATION_MASK);
+	struct spi_message m;
+	struct spi_transfer reg_trans;
+	struct spi_transfer dummy_trans;
+	struct spi_transfer data_trans;
 
 	/* You must take an even number of bytes from the SPU, even if you
 	 * don't care about the last one.  */
···
 
 	spu_transaction_init(card);
 
+	spi_message_init(&m);
+	memset(&reg_trans, 0, sizeof(reg_trans));
+	memset(&dummy_trans, 0, sizeof(dummy_trans));
+	memset(&data_trans, 0, sizeof(data_trans));
+
 	/* write SPU register index */
-	err = spi_write(card->spi, (u8 *)&reg_out, sizeof(u16));
-	if (err)
-		goto out;
+	reg_trans.tx_buf = &reg_out;
+	reg_trans.len = sizeof(reg_out);
+	spi_message_add_tail(&reg_trans, &m);
 
 	delay = spu_reg_is_port_reg(reg) ? card->spu_port_delay :
 						card->spu_reg_delay;
 	if (card->use_dummy_writes) {
 		/* Clock in dummy cycles while the SPU fills the FIFO */
-		for (i = 0; i < delay / 16; ++i) {
-			err = spi_write(card->spi, (u8 *)&zero, sizeof(u16));
-			if (err)
-				return err;
-		}
+		dummy_trans.len = delay / 8;
+		spi_message_add_tail(&dummy_trans, &m);
 	} else {
 		/* Busy-wait while the SPU fills the FIFO */
-		ndelay(100 + (delay * 10));
+		reg_trans.delay_usecs =
+			DIV_ROUND_UP((100 + (delay * 10)), 1000);
 	}
 
 	/* read in data */
-	err = spi_read(card->spi, buf, len);
+	data_trans.rx_buf = buf;
+	data_trans.len = len;
+	spi_message_add_tail(&data_trans, &m);
 
-out:
+	err = spi_sync(card->spi, &m);
 	spu_transaction_finish(card);
 	return err;
 }
···
 	spi_set_drvdata(spi, card);
 	card->pdata = pdata;
 	card->spi = spi;
-	card->gpio_cs = pdata->gpio_cs;
 	card->prev_xfer_time = jiffies;
 
 	sema_init(&card->spi_ready, 0);
···
 	INIT_LIST_HEAD(&card->data_packet_list);
 	spin_lock_init(&card->buffer_lock);
 
-	/* set up GPIO CS line. TODO: use  regular CS line */
-	err = gpio_request(card->gpio_cs, "if_spi_gpio_chip_select");
-	if (err)
-		goto free_card;
-	err = gpio_direction_output(card->gpio_cs, 1);
-	if (err)
-		goto free_gpio;
-
 	/* Initialize the SPI Interface Unit */
 	err = spu_init(card, pdata->use_dummy_writes);
 	if (err)
-		goto free_gpio;
+		goto free_card;
 	err = spu_get_chip_revision(card, &card->card_id, &card->card_rev);
 	if (err)
-		goto free_gpio;
+		goto free_card;
 
 	/* Firmware load */
 	err = spu_read_u32(card, IF_SPI_SCRATCH_4_REG, &scratch);
 	if (err)
-		goto free_gpio;
+		goto free_card;
 	if (scratch == SUCCESSFUL_FW_DOWNLOAD_MAGIC)
 		lbs_deb_spi("Firmware is already loaded for "
 			    "Marvell WLAN 802.11 adapter\n");
···
 		err = if_spi_calculate_fw_names(card->card_id,
 				card->helper_fw_name, card->main_fw_name);
 		if (err)
-			goto free_gpio;
+			goto free_card;
 
 		lbs_deb_spi("Initializing FW for Marvell WLAN 802.11 adapter "
 				"(chip_id = 0x%04x, chip_rev = 0x%02x) "
···
 				spi->max_speed_hz);
 		err = if_spi_prog_helper_firmware(card);
 		if (err)
-			goto free_gpio;
+			goto free_card;
 		err = if_spi_prog_main_firmware(card);
 		if (err)
-			goto free_gpio;
+			goto free_card;
 		lbs_deb_spi("loaded FW for Marvell WLAN 802.11 adapter\n");
 	}
 
 	err = spu_set_interrupt_mode(card, 0, 1);
 	if (err)
-		goto free_gpio;
+		goto free_card;
 
 	/* Register our card with libertas.
 	 * This will call alloc_etherdev */
 	priv = lbs_add_card(card, &spi->dev);
 	if (!priv) {
 		err = -ENOMEM;
-		goto free_gpio;
+		goto free_card;
 	}
 	card->priv = priv;
 	priv->card = card;
···
 	if_spi_terminate_spi_thread(card);
 remove_card:
 	lbs_remove_card(priv); /* will call free_netdev */
-free_gpio:
-	gpio_free(card->gpio_cs);
 free_card:
 	free_if_spi_card(card);
 out:
···
 	free_irq(spi->irq, card);
 	if_spi_terminate_spi_thread(card);
 	lbs_remove_card(priv); /* will call free_netdev */
-	gpio_free(card->gpio_cs);
 	if (card->pdata->teardown)
 		card->pdata->teardown(spi);
 	free_if_spi_card(card);

include/linux/spi/libertas_spi.h

···
 	 * speed, you may want to use 0 here. */
 	u16 use_dummy_writes;
 
-	/* GPIO number to use as chip select */
-	u16 gpio_cs;
-
 	/* Board specific setup/teardown */
 	int (*setup)(struct spi_device *spi);
 	int (*teardown)(struct spi_device *spi);