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Date:   Sat, 24 Sep 2022 16:17:20 +0200
From:   Dominik Brodowski <linux@dominikbrodowski.net>
To:     Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Claudiu Beznea <claudiu.beznea@microchip.com>
Subject: Re: [PATCH] pcmcia: at91_cf: switch to using gpiod API
Message-ID: <Yy8RcC2QHdws26ha@owl.dominikbrodowski.net>
References: <Yy6d7TjqzUwGQnQa@penguin>
 <68c63077-848b-45f5-8aca-ed995391f2b6@www.fastmail.com>
 <Yy7tLRcMaKeet9An@mail.local>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <Yy7tLRcMaKeet9An@mail.local>
Precedence: bulk

Am Sat, Sep 24, 2022 at 01:42:37PM +0200 schrieb Alexandre Belloni:
> On 24/09/2022 10:33:29+0200, Arnd Bergmann wrote:
> > On Sat, Sep 24, 2022, at 8:04 AM, Dmitry Torokhov wrote:
> > > This patch switches the driver to use newer gpiod API instead of legacy
> > > gpio API. This moves us closer to the goal of stopping exporting
> > > OF-specific APIs of gpiolib.
> > >
> > > While at it, stop using module-global for regmap.
> > >
> > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > 
> > This looks good to me overall. Three comments:
> > 
> > > @@ -63,7 +62,7 @@ struct at91_cf_socket {
> > > 
> > >  static inline int at91_cf_present(struct at91_cf_socket *cf)
> > >  {
> > > -	return !gpio_get_value(cf->board->det_pin);
> > > +	return gpiod_get_value(cf->board->det_pin);
> > >  }
> > 
> > a) The change in polarity looks wrong here, I can't really tell
> > from the patch. If this is intentional, maybe explain it in
> > the changelog. With that addressed (either way)
> > 
> > Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> > 
> > 
> > b) In case you are doing more patches like this one at the moment,
> > note that I'm in the process of removing all unused board files
> > for arch/arm/, which will in turn make a lot of drivers unused.
> > I should be able to provide a branch soon, which can be used to
> > identify drivers that don't have DT support any more and don't
> > have any board files. Rather than converting them to gpio
> > descriptors, we can probably just remove those drivers.
> > 
> > c) I'm not sure about the state of the at91_cf driver. Apparently
> > we used to have three drivers for the same hardware (pcmcia,
> > pata and ide), and only the pcmcia driver remained in the tree
> > after drivers/ide/ was removed and pata_at91 did not get converted
> > to DT. I think in the long run we will remove the pcmcia layer,
> > so if you are actually trying to use this hardware, we may want to
> > revive the pata variant and drop this one instead.
> > There is no dts file in tree that actually declares either of them,
> > so chances are that nobody is actually using the CF slot on at91
> > any more.
> > 
> 
> I'm pretty sure it is broken since eaa9a21dd14b ("pcmcia: at91_cf: Use
> syscon to configure the MC/smc") as this change has never been tested.

Well, that's a pretty strong reason to remove this driver. May I get ACKs on
this patch, please?

Thanks,
	Dominik


From: Dominik Brodowski <linux@dominikbrodowski.net>
Subject: [PATCH] pcmcia: remove AT91RM9200 Compact Flash driver

As noted by Arnd Bergmann, "we used to have three drivers for the same
hardware (pcmcia, pata and ide), and only the pcmcia driver remained
in the tree after drivers/ide/ was removed and pata_at91 did not get
converted to DT". "There is no dts file in tree that actually declares
either of them, so chances are that nobody is actually using the CF
slot on at91 any more."[1]

On this rationale, remove the AT91RM9200 Compact Flash driver, which
also assists in reaching "the goal of stopping exporting OF-specific
APIs of gpiolib".[2]

[1] https://lore.kernel.org/lkml/68c63077-848b-45f5-8aca-ed995391f2b6@www.fastmail.com/
[2] https://lore.kernel.org/lkml/Yy6d7TjqzUwGQnQa@penguin/

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

diff --git a/drivers/pcmcia/Kconfig b/drivers/pcmcia/Kconfig
index 90ebc688ec05..1525023e49b6 100644
--- a/drivers/pcmcia/Kconfig
+++ b/drivers/pcmcia/Kconfig
@@ -248,15 +248,6 @@ config OMAP_CF
 	  Say Y here to support the CompactFlash controller on OMAP.
 	  Note that this doesn't support "True IDE" mode.
 
-config AT91_CF
-	tristate "AT91 CompactFlash Controller"
-	depends on PCI
-	depends on OF
-	depends on PCMCIA && ARCH_AT91
-	help
-	  Say Y here to support the CompactFlash controller on AT91 chips.
-	  Or choose M to compile the driver as a module named "at91_cf".
-
 config ELECTRA_CF
 	tristate "Electra CompactFlash Controller"
 	depends on PCMCIA && PPC_PASEMI
diff --git a/drivers/pcmcia/Makefile b/drivers/pcmcia/Makefile
index 1c3ae8888e5f..b3a2accf47af 100644
--- a/drivers/pcmcia/Makefile
+++ b/drivers/pcmcia/Makefile
@@ -30,7 +30,6 @@ obj-$(CONFIG_PCMCIA_SA1100)			+= sa1100_cs.o
 obj-$(CONFIG_PCMCIA_SA1111)			+= sa1111_cs.o
 obj-$(CONFIG_PCMCIA_BCM63XX)			+= bcm63xx_pcmcia.o
 obj-$(CONFIG_OMAP_CF)				+= omap_cf.o
-obj-$(CONFIG_AT91_CF)				+= at91_cf.o
 obj-$(CONFIG_ELECTRA_CF)			+= electra_cf.o
 obj-$(CONFIG_PCMCIA_ALCHEMY_DEVBOARD)		+= db1xxx_ss.o
 obj-$(CONFIG_PCMCIA_MAX1600)			+= max1600.o
diff --git a/drivers/pcmcia/at91_cf.c b/drivers/pcmcia/at91_cf.c
deleted file mode 100644
index c1297f0ebf03..000000000000
--- a/drivers/pcmcia/at91_cf.c
+++ /dev/null
@@ -1,407 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * at91_cf.c -- AT91 CompactFlash controller driver
- *
- * Copyright (C) 2005 David Brownell
- */
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/platform_device.h>
-#include <linux/errno.h>
-#include <linux/init.h>
-#include <linux/interrupt.h>
-#include <linux/slab.h>
-#include <linux/gpio.h>
-#include <linux/io.h>
-#include <linux/sizes.h>
-#include <linux/mfd/syscon.h>
-#include <linux/mfd/syscon/atmel-mc.h>
-#include <linux/of.h>
-#include <linux/of_device.h>
-#include <linux/of_gpio.h>
-#include <linux/pci.h>
-#include <linux/regmap.h>
-
-#include <pcmcia/ss.h>
-
-/*
- * A0..A10 work in each range; A23 indicates I/O space;  A25 is CFRNW;
- * some other bit in {A24,A22..A11} is nREG to flag memory access
- * (vs attributes).  So more than 2KB/region would just be waste.
- * Note: These are offsets from the physical base address.
- */
-#define	CF_ATTR_PHYS	(0)
-#define	CF_IO_PHYS	(1 << 23)
-#define	CF_MEM_PHYS	(0x017ff800)
-
-struct at91_cf_data {
-	int	irq_pin;		/* I/O IRQ */
-	int	det_pin;		/* Card detect */
-	int	vcc_pin;		/* power switching */
-	int	rst_pin;		/* card reset */
-	u8	chipselect;		/* EBI Chip Select number */
-	u8	flags;
-#define AT91_CF_TRUE_IDE	0x01
-#define AT91_IDE_SWAP_A0_A2	0x02
-};
-
-static struct regmap *mc;
-
-/*--------------------------------------------------------------------------*/
-
-struct at91_cf_socket {
-	struct pcmcia_socket	socket;
-
-	unsigned		present:1;
-
-	struct platform_device	*pdev;
-	struct at91_cf_data	*board;
-
-	unsigned long		phys_baseaddr;
-};
-
-static inline int at91_cf_present(struct at91_cf_socket *cf)
-{
-	return !gpio_get_value(cf->board->det_pin);
-}
-
-/*--------------------------------------------------------------------------*/
-
-static int at91_cf_ss_init(struct pcmcia_socket *s)
-{
-	return 0;
-}
-
-static irqreturn_t at91_cf_irq(int irq, void *_cf)
-{
-	struct at91_cf_socket *cf = _cf;
-
-	if (irq == gpio_to_irq(cf->board->det_pin)) {
-		unsigned present = at91_cf_present(cf);
-
-		/* kick pccard as needed */
-		if (present != cf->present) {
-			cf->present = present;
-			dev_dbg(&cf->pdev->dev, "card %s\n",
-					present ? "present" : "gone");
-			pcmcia_parse_events(&cf->socket, SS_DETECT);
-		}
-	}
-
-	return IRQ_HANDLED;
-}
-
-static int at91_cf_get_status(struct pcmcia_socket *s, u_int *sp)
-{
-	struct at91_cf_socket	*cf;
-
-	if (!sp)
-		return -EINVAL;
-
-	cf = container_of(s, struct at91_cf_socket, socket);
-
-	/* NOTE: CF is always 3VCARD */
-	if (at91_cf_present(cf)) {
-		int rdy	= gpio_is_valid(cf->board->irq_pin);	/* RDY/nIRQ */
-		int vcc	= gpio_is_valid(cf->board->vcc_pin);
-
-		*sp = SS_DETECT | SS_3VCARD;
-		if (!rdy || gpio_get_value(cf->board->irq_pin))
-			*sp |= SS_READY;
-		if (!vcc || gpio_get_value(cf->board->vcc_pin))
-			*sp |= SS_POWERON;
-	} else
-		*sp = 0;
-
-	return 0;
-}
-
-static int
-at91_cf_set_socket(struct pcmcia_socket *sock, struct socket_state_t *s)
-{
-	struct at91_cf_socket	*cf;
-
-	cf = container_of(sock, struct at91_cf_socket, socket);
-
-	/* switch Vcc if needed and possible */
-	if (gpio_is_valid(cf->board->vcc_pin)) {
-		switch (s->Vcc) {
-		case 0:
-			gpio_set_value(cf->board->vcc_pin, 0);
-			break;
-		case 33:
-			gpio_set_value(cf->board->vcc_pin, 1);
-			break;
-		default:
-			return -EINVAL;
-		}
-	}
-
-	/* toggle reset if needed */
-	gpio_set_value(cf->board->rst_pin, s->flags & SS_RESET);
-
-	dev_dbg(&cf->pdev->dev, "Vcc %d, io_irq %d, flags %04x csc %04x\n",
-				s->Vcc, s->io_irq, s->flags, s->csc_mask);
-
-	return 0;
-}
-
-static int at91_cf_ss_suspend(struct pcmcia_socket *s)
-{
-	return at91_cf_set_socket(s, &dead_socket);
-}
-
-/* we already mapped the I/O region */
-static int at91_cf_set_io_map(struct pcmcia_socket *s, struct pccard_io_map *io)
-{
-	struct at91_cf_socket	*cf;
-	u32			csr;
-
-	cf = container_of(s, struct at91_cf_socket, socket);
-	io->flags &= (MAP_ACTIVE | MAP_16BIT | MAP_AUTOSZ);
-
-	/*
-	 * Use 16 bit accesses unless/until we need 8-bit i/o space.
-	 *
-	 * NOTE: this CF controller ignores IOIS16, so we can't really do
-	 * MAP_AUTOSZ.  The 16bit mode allows single byte access on either
-	 * D0-D7 (even addr) or D8-D15 (odd), so it's close enough for many
-	 * purposes (and handles ide-cs).
-	 *
-	 * The 8bit mode is needed for odd byte access on D0-D7.  It seems
-	 * some cards only like that way to get at the odd byte, despite
-	 * CF 3.0 spec table 35 also giving the D8-D15 option.
-	 */
-	if (!(io->flags & (MAP_16BIT | MAP_AUTOSZ))) {
-		csr = AT91_MC_SMC_DBW_8;
-		dev_dbg(&cf->pdev->dev, "8bit i/o bus\n");
-	} else {
-		csr = AT91_MC_SMC_DBW_16;
-		dev_dbg(&cf->pdev->dev, "16bit i/o bus\n");
-	}
-	regmap_update_bits(mc, AT91_MC_SMC_CSR(cf->board->chipselect),
-			   AT91_MC_SMC_DBW, csr);
-
-	io->start = cf->socket.io_offset;
-	io->stop = io->start + SZ_2K - 1;
-
-	return 0;
-}
-
-/* pcmcia layer maps/unmaps mem regions */
-static int
-at91_cf_set_mem_map(struct pcmcia_socket *s, struct pccard_mem_map *map)
-{
-	struct at91_cf_socket	*cf;
-
-	if (map->card_start)
-		return -EINVAL;
-
-	cf = container_of(s, struct at91_cf_socket, socket);
-
-	map->flags &= (MAP_ACTIVE | MAP_ATTRIB | MAP_16BIT);
-	if (map->flags & MAP_ATTRIB)
-		map->static_start = cf->phys_baseaddr + CF_ATTR_PHYS;
-	else
-		map->static_start = cf->phys_baseaddr + CF_MEM_PHYS;
-
-	return 0;
-}
-
-static struct pccard_operations at91_cf_ops = {
-	.init			= at91_cf_ss_init,
-	.suspend		= at91_cf_ss_suspend,
-	.get_status		= at91_cf_get_status,
-	.set_socket		= at91_cf_set_socket,
-	.set_io_map		= at91_cf_set_io_map,
-	.set_mem_map		= at91_cf_set_mem_map,
-};
-
-/*--------------------------------------------------------------------------*/
-
-static const struct of_device_id at91_cf_dt_ids[] = {
-	{ .compatible = "atmel,at91rm9200-cf" },
-	{ /* sentinel */ }
-};
-MODULE_DEVICE_TABLE(of, at91_cf_dt_ids);
-
-static int at91_cf_probe(struct platform_device *pdev)
-{
-	struct at91_cf_socket	*cf;
-	struct at91_cf_data	*board;
-	struct resource		*io;
-	struct resource		realio;
-	int			status;
-
-	board = devm_kzalloc(&pdev->dev, sizeof(*board), GFP_KERNEL);
-	if (!board)
-		return -ENOMEM;
-
-	board->irq_pin = of_get_gpio(pdev->dev.of_node, 0);
-	board->det_pin = of_get_gpio(pdev->dev.of_node, 1);
-	board->vcc_pin = of_get_gpio(pdev->dev.of_node, 2);
-	board->rst_pin = of_get_gpio(pdev->dev.of_node, 3);
-
-	mc = syscon_regmap_lookup_by_compatible("atmel,at91rm9200-sdramc");
-	if (IS_ERR(mc))
-		return PTR_ERR(mc);
-
-	if (!gpio_is_valid(board->det_pin) || !gpio_is_valid(board->rst_pin))
-		return -ENODEV;
-
-	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!io)
-		return -ENODEV;
-
-	cf = devm_kzalloc(&pdev->dev, sizeof(*cf), GFP_KERNEL);
-	if (!cf)
-		return -ENOMEM;
-
-	cf->board = board;
-	cf->pdev = pdev;
-	cf->phys_baseaddr = io->start;
-	platform_set_drvdata(pdev, cf);
-
-	/* must be a GPIO; ergo must trigger on both edges */
-	status = devm_gpio_request(&pdev->dev, board->det_pin, "cf_det");
-	if (status < 0)
-		return status;
-
-	status = devm_request_irq(&pdev->dev, gpio_to_irq(board->det_pin),
-					at91_cf_irq, 0, "at91_cf detect", cf);
-	if (status < 0)
-		return status;
-
-	device_init_wakeup(&pdev->dev, 1);
-
-	status = devm_gpio_request(&pdev->dev, board->rst_pin, "cf_rst");
-	if (status < 0)
-		goto fail0a;
-
-	if (gpio_is_valid(board->vcc_pin)) {
-		status = devm_gpio_request(&pdev->dev, board->vcc_pin, "cf_vcc");
-		if (status < 0)
-			goto fail0a;
-	}
-
-	/*
-	 * The card driver will request this irq later as needed.
-	 * but it causes lots of "irqNN: nobody cared" messages
-	 * unless we report that we handle everything (sigh).
-	 * (Note:  DK board doesn't wire the IRQ pin...)
-	 */
-	if (gpio_is_valid(board->irq_pin)) {
-		status = devm_gpio_request(&pdev->dev, board->irq_pin, "cf_irq");
-		if (status < 0)
-			goto fail0a;
-
-		status = devm_request_irq(&pdev->dev, gpio_to_irq(board->irq_pin),
-					at91_cf_irq, IRQF_SHARED, "at91_cf", cf);
-		if (status < 0)
-			goto fail0a;
-		cf->socket.pci_irq = gpio_to_irq(board->irq_pin);
-	} else
-		cf->socket.pci_irq = nr_irqs + 1;
-
-	/*
-	 * pcmcia layer only remaps "real" memory not iospace
-	 * io_offset is set to 0x10000 to avoid the check in static_find_io().
-	 * */
-	cf->socket.io_offset = 0x10000;
-	realio.start = cf->socket.io_offset;
-	realio.end = realio.start + SZ_64K - 1;
-	status = pci_remap_iospace(&realio, cf->phys_baseaddr + CF_IO_PHYS);
-	if (status)
-		goto fail0a;
-
-	/* reserve chip-select regions */
-	if (!devm_request_mem_region(&pdev->dev, io->start, resource_size(io), "at91_cf")) {
-		status = -ENXIO;
-		goto fail0a;
-	}
-
-	dev_info(&pdev->dev, "irqs det #%d, io #%d\n",
-		gpio_to_irq(board->det_pin), gpio_to_irq(board->irq_pin));
-
-	cf->socket.owner = THIS_MODULE;
-	cf->socket.dev.parent = &pdev->dev;
-	cf->socket.ops = &at91_cf_ops;
-	cf->socket.resource_ops = &pccard_static_ops;
-	cf->socket.features = SS_CAP_PCCARD | SS_CAP_STATIC_MAP
-				| SS_CAP_MEM_ALIGN;
-	cf->socket.map_size = SZ_2K;
-	cf->socket.io[0].res = io;
-
-	status = pcmcia_register_socket(&cf->socket);
-	if (status < 0)
-		goto fail0a;
-
-	return 0;
-
-fail0a:
-	device_init_wakeup(&pdev->dev, 0);
-	return status;
-}
-
-static int at91_cf_remove(struct platform_device *pdev)
-{
-	struct at91_cf_socket	*cf = platform_get_drvdata(pdev);
-
-	pcmcia_unregister_socket(&cf->socket);
-	device_init_wakeup(&pdev->dev, 0);
-
-	return 0;
-}
-
-#ifdef	CONFIG_PM
-
-static int at91_cf_suspend(struct platform_device *pdev, pm_message_t mesg)
-{
-	struct at91_cf_socket	*cf = platform_get_drvdata(pdev);
-	struct at91_cf_data	*board = cf->board;
-
-	if (device_may_wakeup(&pdev->dev)) {
-		enable_irq_wake(gpio_to_irq(board->det_pin));
-		if (gpio_is_valid(board->irq_pin))
-			enable_irq_wake(gpio_to_irq(board->irq_pin));
-	}
-	return 0;
-}
-
-static int at91_cf_resume(struct platform_device *pdev)
-{
-	struct at91_cf_socket	*cf = platform_get_drvdata(pdev);
-	struct at91_cf_data	*board = cf->board;
-
-	if (device_may_wakeup(&pdev->dev)) {
-		disable_irq_wake(gpio_to_irq(board->det_pin));
-		if (gpio_is_valid(board->irq_pin))
-			disable_irq_wake(gpio_to_irq(board->irq_pin));
-	}
-
-	return 0;
-}
-
-#else
-#define	at91_cf_suspend		NULL
-#define	at91_cf_resume		NULL
-#endif
-
-static struct platform_driver at91_cf_driver = {
-	.driver = {
-		.name		= "at91_cf",
-		.of_match_table = at91_cf_dt_ids,
-	},
-	.probe		= at91_cf_probe,
-	.remove		= at91_cf_remove,
-	.suspend	= at91_cf_suspend,
-	.resume		= at91_cf_resume,
-};
-
-module_platform_driver(at91_cf_driver);
-
-MODULE_DESCRIPTION("AT91 Compact Flash Driver");
-MODULE_AUTHOR("David Brownell");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:at91_cf");