Add DT property "m25p,fast-read" that signalises the particular chip supports "fast read" opcode.
Signed-off-by: Marek Vasut <[email protected]> Cc: Artem Bityutskiy <[email protected]> Cc: David Woodhouse <[email protected]> --- Documentation/devicetree/bindings/mtd/m25p80.txt | 29 ++++++++++++++++++++ drivers/mtd/devices/m25p80.c | 32 +++++++++++++--------- 2 files changed, 48 insertions(+), 13 deletions(-) create mode 100644 Documentation/devicetree/bindings/mtd/m25p80.txt V2: Add documentation for the DT property. V3: Use of_property_get_bool() instead of of_find_property(). V4: Adjust the documentation's "compatible:" section, make it not Linux-specific, but keep the reference to Linux's list of supported devices. Also, use the default name, spansion,m25p80 in the example. diff --git a/Documentation/devicetree/bindings/mtd/m25p80.txt b/Documentation/devicetree/bindings/mtd/m25p80.txt new file mode 100644 index 0000000..701bb58 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/m25p80.txt @@ -0,0 +1,29 @@ +* MTD SPI driver for ST M25Pxx (and similar) serial flash chips + +Required properties: +- #address-cells, #size-cells : Must be present if the device has sub-nodes + representing partitions. +- compatible : Should be the manufacturer and the name of the chip. Bear in mind + the DT binding is not Linux-only, but in case of Linux, see the + "m25p_ids" table in drivers/mtd/devices/m25p80.c for the list of + supported chips. +- reg : Chip-Select number +- spi-max-frequency : Maximum frequency of the SPI bus the chip can operate at + +Optional properties: +- m25p,fast-read : Use the "fast read" opcode to read data from the chip instead + of the usual "read" opcode. This opcode isn not supported by + all chips and support for it can not be detected at runtime. + Refer to your chips' datasheet to check if this is supported + by your chip. + +Example: + + flash: m25p80@0 { + #address-cells = <1>; + #size-cells = <1>; + compatible = "spansion,m25p80"; + reg = <0>; + spi-max-frequency = <40000000>; + m25p,fast-read; + }; diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c index d16f75c..a08d4ec 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); @@ -804,9 +800,10 @@ 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 @@ -858,7 +855,8 @@ 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; @@ -915,6 +913,14 @@ 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_property_read_bool(np, "m25p,fast-read")) + 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 { -- 1.7.10.4 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
