Device tree conversion of spi device vs. controller_data

Hi,

upon DT conversion of LPC32xx, I came across the at25 spi eeprom which needs .controller_data in struct spi_board_info for slave registration via spi_register_board_info() (non-DT-case).

In the DT case, we need to eliminate this explicit registering call. Therefore, I need to somehow replace the .controller_data passing in the DT case to pass this data to the spi core. But I can't find such a mechanism (v3.4-rc2). Is there already a concept or API that I overlooked (please just point me to it) or what can I do to solve this? (Looks like a general issue for spi slave registration via DT).

Quoted 10 lines

upon DT conversion of LPC32xx, I came across the at25 spi eeprom which needs .controller_data in struct spi_board_info for slave registration via spi_register_board_info() (non-DT-case).

In the DT case, we need to eliminate this explicit registering call. Therefore, I need to somehow replace the .controller_data passing in the DT case to pass this data to the spi core. But I can't find such a mechanism (v3.4-rc2). Is there already a concept or API that I overlooked (please just point me to it) or what can I do to solve this? (Looks like a general issue for spi slave registration via DT).

Can you point me at specific code?

.controller_data is owned by the spi_master driver. The eeprom driver shouldn't be accessing it directly at all; but I'll need to look at specific code to really understand what is going on.

Quoted 11 lines · Grant Likely

Quoted 10 lines

upon DT conversion of LPC32xx, I came across the at25 spi eeprom which needs .controller_data in struct spi_board_info for slave registration via spi_register_board_info() (non-DT-case).

In the DT case, we need to eliminate this explicit registering call. Therefore, I need to somehow replace the .controller_data passing in the DT case to pass this data to the spi core. But I can't find such a mechanism (v3.4-rc2). Is there already a concept or API that I overlooked (please just point me to it) or what can I do to solve this? (Looks like a general issue for spi slave registration via DT).

Quoted 5 lines

Can you point me at specific code?

.controller_data is owned by the spi_master driver. The eeprom driver shouldn't be accessing it directly at all; but I'll need to look at specific code to really understand what is going on.

Please have a look at arch/arm/mach-lpc32xx/phy3250.c :

static struct pl022_config_chip spi0_chip_info = {

        .com_mode               = INTERRUPT_TRANSFER,
        .iface                  = SSP_INTERFACE_MOTOROLA_SPI,
        .hierarchy              = SSP_MASTER,
        .slave_tx_disable       = 0,
        .rx_lev_trig            = SSP_RX_4_OR_MORE_ELEM,
        .tx_lev_trig            = SSP_TX_4_OR_MORE_EMPTY_LOC,
        .ctrl_len               = SSP_BITS_8,
        .wait_state             = SSP_MWIRE_WAIT_ZERO,
        .duplex                 = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
        .cs_control             = phy3250_spi_cs_set,

};

...

        static struct spi_eeprom eeprom = {
                .name = "at25256a",
                .byte_len = 0x8000,
                .page_size = 64,
                .flags = EE_ADDR2,

        };

        static struct spi_board_info info[] = {
                {
                        .modalias = "at25",

                        .max_speed_hz = 5000000,
                        .bus_num = 0,
                        .chip_select = 0,
                        .mode = SPI_MODE_0,
                        .platform_data = &eeprom,
                        .controller_data = &spi0_chip_info,
                },
        };

	spi_register_board_info(info, ARRAY_SIZE(info));

Trying to replace .controller_data at this point with device tree settings passing, I struggled with missing resp. node properties.

Any hint how this can be done?

Thanks in advance,

Roland

Quoted 9 lines

Quoted 5 lines

Can you point me at specific code?

.controller_data is owned by the spi_master driver. The eeprom driver shouldn't be accessing it directly at all; but I'll need to look at specific code to really understand what is going on.

Please have a look at arch/arm/mach-lpc32xx/phy3250.c :

static struct pl022_config_chip spi0_chip_info = {

Quoted 10 lines

        .com_mode               = INTERRUPT_TRANSFER,
        .iface                  = SSP_INTERFACE_MOTOROLA_SPI,
        .hierarchy              = SSP_MASTER,
        .slave_tx_disable       = 0,
        .rx_lev_trig            = SSP_RX_4_OR_MORE_ELEM,
        .tx_lev_trig            = SSP_TX_4_OR_MORE_EMPTY_LOC,
        .ctrl_len               = SSP_BITS_8,
        .wait_state             = SSP_MWIRE_WAIT_ZERO,
        .duplex                 = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
        .cs_control             = phy3250_spi_cs_set,

phy3250_spi_cs_set is only a wrapper around gpio_set_value(). GPIO CS manipulation should be handled by the core pl022 spi driver, so that gets rid of the hardest part of this conversion (callbacks in platform data).

The pl022_config_chip structure is 100% owned by the spi controller (pl022). If the bus driver depends on this structure, then it is the responsibility of the bus driver to allocate one and set the controller data pointer for each of the child devices. You may need to add pl022-specific properties to each of the child nodes to populate this data correctly if it cannot be determined with other means.