Patchwork [3/3,RFC] mtd: m25p80: Make fast read configurable via DT

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Submitter Marek Vasut
Date July 6, 2012, 6:10 a.m.
Message ID <1341555027-17462-3-git-send-email-marex@denx.de>
Download mbox | patch
Permalink /patch/169332/
State RFC
Headers show

Comments

Marek Vasut - July 6, 2012, 6:10 a.m.
Add DT property "m25p,fast-read" that signalises the particular
chip supports "fast read" opcode.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: David Woodhouse <david.woodhouse@intel.com>
---
 drivers/mtd/devices/m25p80.c |   32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

NOTE: I'm not sure where to document this property, as m25p80 is
      a simple DT device. Any hints please?
Stefan Roese - July 6, 2012, 6:43 a.m.
Hi Marek,

On Friday 06 July 2012 08:10:27 Marek Vasut wrote:
> @@ -914,6 +912,14 @@ static int __devinit m25p_probe(struct spi_device
> *spi) flash->page_size = info->page_size;
>  	flash->mtd.writebufsize = flash->page_size;
> 
> +	flash->fast_read = false;
> +	if (np && of_find_property(np, "m25p,fast-read", NULL))
> +		flash->fast_read = true;
> +
> +#ifdef CONFIG_M25PXX_USE_FAST_READ
> +	flash->fast_read = true;
> +#endif
> +

Better use of_property_read_bool() instead of of_find_property() here.

Thanks,
Stefan
Marek Vasut - July 9, 2012, 8:13 a.m.
Dear Marek Vasut,

> Add DT property "m25p,fast-read" that signalises the particular
> chip supports "fast read" opcode.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
> Cc: David Woodhouse <david.woodhouse@intel.com>
> ---
>  drivers/mtd/devices/m25p80.c |   32 +++++++++++++++++++-------------
>  1 file changed, 19 insertions(+), 13 deletions(-)
> 
> NOTE: I'm not sure where to document this property, as m25p80 is
>       a simple DT device. Any hints please?
> 
   ^--- bump?

Best regards,
Marek Vasut
Mike Frysinger - July 11, 2012, 2:38 p.m.
On Mon, Jul 9, 2012 at 10:13 AM, Marek Vasut <marex@denx.de> wrote:
> > Add DT property "m25p,fast-read" that signalises the particular
> > chip supports "fast read" opcode.
> >
> > Signed-off-by: Marek Vasut <marex@denx.de>
> > Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
> > Cc: David Woodhouse <david.woodhouse@intel.com>
> > ---
> >  drivers/mtd/devices/m25p80.c |   32 +++++++++++++++++++-------------
> >  1 file changed, 19 insertions(+), 13 deletions(-)
> >
> > NOTE: I'm not sure where to document this property, as m25p80 is
> >       a simple DT device. Any hints please?
> >
>    ^--- bump?

did you see Stefan's suggestion ?
-mike
Marek Vasut - July 13, 2012, 10:44 a.m.
Dear Mike Frysinger,

> On Mon, Jul 9, 2012 at 10:13 AM, Marek Vasut <marex@denx.de> wrote:
> > > Add DT property "m25p,fast-read" that signalises the particular
> > > chip supports "fast read" opcode.
> > > 
> > > Signed-off-by: Marek Vasut <marex@denx.de>
> > > Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
> > > Cc: David Woodhouse <david.woodhouse@intel.com>
> > > ---
> > > 
> > >  drivers/mtd/devices/m25p80.c |   32 +++++++++++++++++++-------------
> > >  1 file changed, 19 insertions(+), 13 deletions(-)
> > > 
> > > NOTE: I'm not sure where to document this property, as m25p80 is
> > > 
> > >       a simple DT device. Any hints please?
> >    
> >    ^--- bump?
> 
> did you see Stefan's suggestion ?
> -mike

The one which wasn't about documentation but usage of different OF function? 
Yes.

Best regards,
Marek Vasut

Patch

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 28e841d..08019b8 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -73,14 +73,6 @@ 
 #define	MAX_READY_WAIT_JIFFIES	(40 * HZ)	/* M25P16 specs 40s max chip erase */
 #define	MAX_CMD_SIZE		5
 
-#ifdef CONFIG_M25PXX_USE_FAST_READ
-#define OPCODE_READ 	OPCODE_FAST_READ
-#define FAST_READ_DUMMY_BYTE 1
-#else
-#define OPCODE_READ 	OPCODE_NORM_READ
-#define FAST_READ_DUMMY_BYTE 0
-#endif
-
 #define JEDEC_MFR(_jedec_id)	((_jedec_id) >> 16)
 
 /****************************************************************************/
@@ -93,6 +85,7 @@  struct m25p {
 	u16			addr_width;
 	u8			erase_opcode;
 	u8			*command;
+	bool			fast_read;
 };
 
 static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
@@ -342,6 +335,7 @@  static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
 	struct m25p *flash = mtd_to_m25p(mtd);
 	struct spi_transfer t[2];
 	struct spi_message m;
+	uint8_t opcode;
 
 	pr_debug("%s: %s from 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
 			__func__, (u32)from, len);
@@ -354,7 +348,7 @@  static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
 	 * Should add 1 byte DUMMY_BYTE.
 	 */
 	t[0].tx_buf = flash->command;
-	t[0].len = m25p_cmdsz(flash) + FAST_READ_DUMMY_BYTE;
+	t[0].len = m25p_cmdsz(flash) + (flash->fast_read ? 1 : 0);
 	spi_message_add_tail(&t[0], &m);
 
 	t[1].rx_buf = buf;
@@ -376,12 +370,14 @@  static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
 	 */
 
 	/* Set up the write data buffer. */
-	flash->command[0] = OPCODE_READ;
+	opcode = flash->fast_read ? OPCODE_FAST_READ : OPCODE_NORM_READ;
+	flash->command[0] = opcode;
 	m25p_addr2cmd(flash, from, flash->command);
 
 	spi_sync(flash->spi, &m);
 
-	*retlen = m.actual_length - m25p_cmdsz(flash) - FAST_READ_DUMMY_BYTE;
+	*retlen = m.actual_length - m25p_cmdsz(flash) -
+			(flash->fast_read ? 1 : 0);
 
 	mutex_unlock(&flash->lock);
 
@@ -803,9 +799,10 @@  static int __devinit m25p_probe(struct spi_device *spi)
 	struct flash_info		*info;
 	unsigned			i;
 	struct mtd_part_parser_data	ppdata;
+	struct device_node		*np = spi->dev.of_node;
 
 #ifdef CONFIG_MTD_OF_PARTS
-	if (!of_device_is_available(spi->dev.of_node))
+	if (!of_device_is_available(np))
 		return -ENODEV;
 #endif
 
@@ -857,7 +854,8 @@  static int __devinit m25p_probe(struct spi_device *spi)
 	flash = kzalloc(sizeof *flash, GFP_KERNEL);
 	if (!flash)
 		return -ENOMEM;
-	flash->command = kmalloc(MAX_CMD_SIZE + FAST_READ_DUMMY_BYTE, GFP_KERNEL);
+	flash->command = kmalloc(MAX_CMD_SIZE + (flash->fast_read ? 1 : 0),
+					GFP_KERNEL);
 	if (!flash->command) {
 		kfree(flash);
 		return -ENOMEM;
@@ -914,6 +912,14 @@  static int __devinit m25p_probe(struct spi_device *spi)
 	flash->page_size = info->page_size;
 	flash->mtd.writebufsize = flash->page_size;
 
+	flash->fast_read = false;
+	if (np && of_find_property(np, "m25p,fast-read", NULL))
+		flash->fast_read = true;
+
+#ifdef CONFIG_M25PXX_USE_FAST_READ
+	flash->fast_read = true;
+#endif
+
 	if (info->addr_width)
 		flash->addr_width = info->addr_width;
 	else {