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Message-Id: <0e1bcf3a-e8d7-9f50-bdf7-2a1e7466665b@linux.vnet.ibm.com>
Date: Thu, 30 Mar 2017 13:15:49 -0500
From: Christopher Bostic <cbostic@...ux.vnet.ibm.com>
To: Joel Stanley <joel@....id.au>
Cc: Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Russell King <linux@...linux.org.uk>, rostedt@...dmis.org,
mingo@...hat.com, Greg KH <gregkh@...uxfoundation.org>,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Andrew Jeffery <andrew@...id.au>,
Alistair Popple <alistair@...ple.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
"Edward A . James" <eajames@...ibm.com>,
Jeremy Kerr <jk@...abs.org>
Subject: Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master
On 3/30/17 12:48 AM, Joel Stanley wrote:
> On Thu, Mar 30, 2017 at 4:13 AM, Christopher Bostic
> <cbostic@...ux.vnet.ibm.com> wrote:
>> From: Chris Bostic <cbostic@...ux.vnet.ibm.com>
>>
>> Implement a FSI master using GPIO. Will generate FSI protocol for
>> read and write commands to particular addresses. Sends master command
>> and waits for and decodes a slave response.
>>
>> Includes changes from Edward A. James <eajames@...ibm.com> and Jeremy
>> Kerr <jk@...abs.org>.
>>
>> Signed-off-by: Edward A. James <eajames@...ibm.com>
>> Signed-off-by: Jeremy Kerr <jk@...abs.org>
>> Signed-off-by: Chris Bostic <cbostic@...ux.vnet.ibm.com>
>> Signed-off-by: Joel Stanley <joel@....id.au>
>> ---
>> arch/arm/boot/dts/aspeed-bmc-opp-palmetto.dts | 10 +
>> arch/arm/boot/dts/aspeed-bmc-opp-romulus.dts | 12 +
>> drivers/fsi/Kconfig | 11 +
>> drivers/fsi/Makefile | 1 +
>> drivers/fsi/fsi-master-gpio.c | 614 ++++++++++++++++++++++++++
>> 5 files changed, 648 insertions(+)
>> create mode 100644 drivers/fsi/fsi-master-gpio.c
>>
>> diff --git a/arch/arm/boot/dts/aspeed-bmc-opp-palmetto.dts b/arch/arm/boot/dts/aspeed-bmc-opp-palmetto.dts
>> index 1d2fc1e..cf7d7d7 100644
>> --- a/arch/arm/boot/dts/aspeed-bmc-opp-palmetto.dts
>> +++ b/arch/arm/boot/dts/aspeed-bmc-opp-palmetto.dts
>> @@ -29,6 +29,16 @@
>> reg = <0x5f000000 0x01000000>; /* 16M */
>> };
>> };
>> +
>> + gpio-fsi {
>> + compatible = "fsi-master-gpio", "fsi-master";
>> +
>> + clock-gpios = <&gpio ASPEED_GPIO(A, 4) GPIO_ACTIVE_HIGH>;
>> + data-gpios = <&gpio ASPEED_GPIO(A, 5) GPIO_ACTIVE_HIGH>;
>> + mux-gpios = <&gpio ASPEED_GPIO(A, 6) GPIO_ACTIVE_HIGH>;
>> + enable-gpios = <&gpio ASPEED_GPIO(D, 0) GPIO_ACTIVE_HIGH>;
>> + trans-gpios = <&gpio ASPEED_GPIO(H, 6) GPIO_ACTIVE_HIGH>;
>> + };
>> };
>>
>> &uart5 {
>> diff --git a/arch/arm/boot/dts/aspeed-bmc-opp-romulus.dts b/arch/arm/boot/dts/aspeed-bmc-opp-romulus.dts
>> index 7a3b2b5..2fd7db7 100644
>> --- a/arch/arm/boot/dts/aspeed-bmc-opp-romulus.dts
>> +++ b/arch/arm/boot/dts/aspeed-bmc-opp-romulus.dts
>> @@ -29,6 +29,18 @@
>> reg = <0xbf000000 0x01000000>; /* 16M */
>> };
>> };
>> +
>> + gpio-fsi {
>> + compatible = "fsi-master-gpio", "fsi-master";
>> +
>> + status = "okay";
>> +
>> + clock-gpios = <&gpio ASPEED_GPIO(AA, 0) GPIO_ACTIVE_HIGH>;
>> + data-gpios = <&gpio ASPEED_GPIO(AA, 2) GPIO_ACTIVE_HIGH>;
>> + mux-gpios = <&gpio ASPEED_GPIO(A, 6) GPIO_ACTIVE_HIGH>;
>> + enable-gpios = <&gpio ASPEED_GPIO(D, 0) GPIO_ACTIVE_HIGH>;
>> + trans-gpios = <&gpio ASPEED_GPIO(R, 2) GPIO_ACTIVE_HIGH>;
>> + };
>> };
> I'm not sure what happened here. The changes to the device trees
> should not be in this patch.
Where would you recommend they be placed? I assume we want them
somewhere in the patch set.
Thanks,
Chris
> Cheers,
>
> Joel
>
>> &uart5 {
>> diff --git a/drivers/fsi/Kconfig b/drivers/fsi/Kconfig
>> index 04c1a0e..9cf8345 100644
>> --- a/drivers/fsi/Kconfig
>> +++ b/drivers/fsi/Kconfig
>> @@ -9,4 +9,15 @@ config FSI
>> ---help---
>> FSI - the FRU Support Interface - is a simple bus for low-level
>> access to POWER-based hardware.
>> +
>> +if FSI
>> +
>> +config FSI_MASTER_GPIO
>> + tristate "GPIO-based FSI master"
>> + depends on FSI && GPIOLIB
>> + ---help---
>> + This option enables a FSI master driver using GPIO lines.
>> +
>> +endif
>> +
>> endmenu
>> diff --git a/drivers/fsi/Makefile b/drivers/fsi/Makefile
>> index db0e5e7..ed28ac0 100644
>> --- a/drivers/fsi/Makefile
>> +++ b/drivers/fsi/Makefile
>> @@ -1,2 +1,3 @@
>>
>> obj-$(CONFIG_FSI) += fsi-core.o
>> +obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
>> diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c
>> new file mode 100644
>> index 0000000..0bf5caa
>> --- /dev/null
>> +++ b/drivers/fsi/fsi-master-gpio.c
>> @@ -0,0 +1,614 @@
>> +/*
>> + * A FSI master controller, using a simple GPIO bit-banging interface
>> + */
>> +
>> +#include <linux/platform_device.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/module.h>
>> +#include <linux/delay.h>
>> +#include <linux/fsi.h>
>> +#include <linux/device.h>
>> +#include <linux/io.h>
>> +#include <linux/slab.h>
>> +#include <linux/spinlock.h>
>> +
>> +#include "fsi-master.h"
>> +
>> +#define FSI_GPIO_STD_DLY 1 /* Standard pin delay in nS */
>> +#define FSI_ECHO_DELAY_CLOCKS 16 /* Number clocks for echo delay */
>> +#define FSI_PRE_BREAK_CLOCKS 50 /* Number clocks to prep for break */
>> +#define FSI_BREAK_CLOCKS 256 /* Number of clocks to issue break */
>> +#define FSI_POST_BREAK_CLOCKS 16000 /* Number clocks to set up cfam */
>> +#define FSI_INIT_CLOCKS 5000 /* Clock out any old data */
>> +#define FSI_GPIO_STD_DELAY 10 /* Standard GPIO delay in nS */
>> + /* todo: adjust down as low as */
>> + /* possible or eliminate */
>> +#define FSI_GPIO_CMD_DPOLL 0x2
>> +#define FSI_GPIO_CMD_TERM 0x3f
>> +#define FSI_GPIO_CMD_ABS_AR 0x4
>> +
>> +#define FSI_GPIO_DPOLL_CLOCKS 100 /* < 21 will cause slave to hang */
>> +
>> +/* Bus errors */
>> +#define FSI_GPIO_ERR_BUSY 1 /* Slave stuck in busy state */
>> +#define FSI_GPIO_RESP_ERRA 2 /* Any (misc) Error */
>> +#define FSI_GPIO_RESP_ERRC 3 /* Slave reports master CRC error */
>> +#define FSI_GPIO_MTOE 4 /* Master time out error */
>> +#define FSI_GPIO_CRC_INVAL 5 /* Master reports slave CRC error */
>> +
>> +/* Normal slave responses */
>> +#define FSI_GPIO_RESP_BUSY 1
>> +#define FSI_GPIO_RESP_ACK 0
>> +#define FSI_GPIO_RESP_ACKD 4
>> +
>> +#define FSI_GPIO_MAX_BUSY 100
>> +#define FSI_GPIO_MTOE_COUNT 1000
>> +#define FSI_GPIO_DRAIN_BITS 20
>> +#define FSI_GPIO_CRC_SIZE 4
>> +#define FSI_GPIO_MSG_ID_SIZE 2
>> +#define FSI_GPIO_MSG_RESPID_SIZE 2
>> +#define FSI_GPIO_PRIME_SLAVE_CLOCKS 100
>> +
>> +static DEFINE_SPINLOCK(fsi_gpio_cmd_lock); /* lock around fsi commands */
>> +
>> +struct fsi_master_gpio {
>> + struct fsi_master master;
>> + struct device *dev;
>> + struct gpio_desc *gpio_clk;
>> + struct gpio_desc *gpio_data;
>> + struct gpio_desc *gpio_trans; /* Voltage translator */
>> + struct gpio_desc *gpio_enable; /* FSI enable */
>> + struct gpio_desc *gpio_mux; /* Mux control */
>> +};
>> +
>> +#define to_fsi_master_gpio(m) container_of(m, struct fsi_master_gpio, master)
>> +
>> +struct fsi_gpio_msg {
>> + uint64_t msg;
>> + uint8_t bits;
>> +};
>> +
>> +static void clock_toggle(struct fsi_master_gpio *master, int count)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < count; i++) {
>> + ndelay(FSI_GPIO_STD_DLY);
>> + gpiod_set_value(master->gpio_clk, 0);
>> + ndelay(FSI_GPIO_STD_DLY);
>> + gpiod_set_value(master->gpio_clk, 1);
>> + }
>> +}
>> +
>> +static int sda_in(struct fsi_master_gpio *master)
>> +{
>> + int in;
>> +
>> + ndelay(FSI_GPIO_STD_DLY);
>> + in = gpiod_get_value(master->gpio_data);
>> + return in ? 1 : 0;
>> +}
>> +
>> +static void sda_out(struct fsi_master_gpio *master, int value)
>> +{
>> + gpiod_set_value(master->gpio_data, value);
>> +}
>> +
>> +static void set_sda_input(struct fsi_master_gpio *master)
>> +{
>> + gpiod_direction_input(master->gpio_data);
>> + if (master->gpio_trans)
>> + gpiod_set_value(master->gpio_trans, 0);
>> +}
>> +
>> +static void set_sda_output(struct fsi_master_gpio *master, int value)
>> +{
>> + if (master->gpio_trans)
>> + gpiod_set_value(master->gpio_trans, 1);
>> + gpiod_direction_output(master->gpio_data, value);
>> +}
>> +
>> +static void clock_zeros(struct fsi_master_gpio *master, int count)
>> +{
>> + set_sda_output(master, 1);
>> + clock_toggle(master, count);
>> +}
>> +
>> +static void serial_in(struct fsi_master_gpio *master, struct fsi_gpio_msg *msg,
>> + uint8_t num_bits)
>> +{
>> + uint8_t bit, in_bit;
>> +
>> + set_sda_input(master);
>> +
>> + for (bit = 0; bit < num_bits; bit++) {
>> + clock_toggle(master, 1);
>> + in_bit = sda_in(master);
>> + msg->msg <<= 1;
>> + msg->msg |= ~in_bit & 0x1; /* Data is negative active */
>> + }
>> + msg->bits += num_bits;
>> +}
>> +
>> +static void serial_out(struct fsi_master_gpio *master,
>> + const struct fsi_gpio_msg *cmd)
>> +{
>> + uint8_t bit;
>> + uint64_t msg = ~cmd->msg; /* Data is negative active */
>> + uint64_t sda_mask = 0x1ULL << (cmd->bits - 1);
>> + uint64_t last_bit = ~0;
>> + int next_bit;
>> +
>> + if (!cmd->bits) {
>> + dev_warn(master->dev, "trying to output 0 bits\n");
>> + return;
>> + }
>> + set_sda_output(master, 0);
>> +
>> + /* Send the start bit */
>> + sda_out(master, 0);
>> + clock_toggle(master, 1);
>> +
>> + /* Send the message */
>> + for (bit = 0; bit < cmd->bits; bit++) {
>> + next_bit = (msg & sda_mask) >> (cmd->bits - 1);
>> + if (last_bit ^ next_bit) {
>> + sda_out(master, next_bit);
>> + last_bit = next_bit;
>> + }
>> + clock_toggle(master, 1);
>> + msg <<= 1;
>> + }
>> +}
>> +
>> +static void msg_push_bits(struct fsi_gpio_msg *msg, uint64_t data, int bits)
>> +{
>> + msg->msg <<= bits;
>> + msg->msg |= data & ((1ull << bits) - 1);
>> + msg->bits += bits;
>> +}
>> +
>> +static void msg_push_crc(struct fsi_gpio_msg *msg)
>> +{
>> + uint8_t crc;
>> + int top;
>> +
>> + top = msg->bits & 0x3;
>> +
>> + /* start bit, and any non-aligned top bits */
>> + crc = fsi_crc4(0,
>> + 1 << top | msg->msg >> (msg->bits - top),
>> + top + 1);
>> +
>> + /* aligned bits */
>> + crc = fsi_crc4(crc, msg->msg, msg->bits - top);
>> +
>> + msg_push_bits(msg, crc, 4);
>> +}
>> +
>> +static void build_abs_ar_command(struct fsi_gpio_msg *cmd,
>> + uint8_t id, uint32_t addr, size_t size, const void *data)
>> +{
>> + bool write = !!data;
>> + uint8_t ds;
>> + int i;
>> +
>> + cmd->bits = 0;
>> + cmd->msg = 0;
>> +
>> + msg_push_bits(cmd, id, 2);
>> + msg_push_bits(cmd, FSI_GPIO_CMD_ABS_AR, 3);
>> + msg_push_bits(cmd, write ? 0 : 1, 1);
>> +
>> + /*
>> + * The read/write size is encoded in the lower bits of the address
>> + * (as it must be naturally-aligned), and the following ds bit.
>> + *
>> + * size addr:1 addr:0 ds
>> + * 1 x x 0
>> + * 2 x 0 1
>> + * 4 0 1 1
>> + *
>> + */
>> + ds = size > 1 ? 1 : 0;
>> + addr &= ~(size - 1);
>> + if (size == 4)
>> + addr |= 1;
>> +
>> + msg_push_bits(cmd, addr & ((1 << 21) - 1), 21);
>> + msg_push_bits(cmd, ds, 1);
>> + for (i = 0; write && i < size; i++)
>> + msg_push_bits(cmd, ((uint8_t *)data)[i], 8);
>> +
>> + msg_push_crc(cmd);
>> +}
>> +
>> +static void build_dpoll_command(struct fsi_gpio_msg *cmd, uint8_t slave_id)
>> +{
>> + cmd->bits = 0;
>> + cmd->msg = 0;
>> +
>> + msg_push_bits(cmd, slave_id, 2);
>> + msg_push_bits(cmd, FSI_GPIO_CMD_DPOLL, 3);
>> + msg_push_crc(cmd);
>> +}
>> +
>> +static void echo_delay(struct fsi_master_gpio *master)
>> +{
>> + set_sda_output(master, 1);
>> + clock_toggle(master, FSI_ECHO_DELAY_CLOCKS);
>> +}
>> +
>> +static void build_term_command(struct fsi_gpio_msg *cmd, uint8_t slave_id)
>> +{
>> + cmd->bits = 0;
>> + cmd->msg = 0;
>> +
>> + msg_push_bits(cmd, slave_id, 2);
>> + msg_push_bits(cmd, FSI_GPIO_CMD_TERM, 6);
>> + msg_push_crc(cmd);
>> +}
>> +
>> +/*
>> + * Store information on master errors so handler can detect and clean
>> + * up the bus
>> + */
>> +static void fsi_master_gpio_error(struct fsi_master_gpio *master, int error)
>> +{
>> +
>> +}
>> +
>> +static int read_one_response(struct fsi_master_gpio *master,
>> + uint8_t data_size, struct fsi_gpio_msg *msgp, uint8_t *tagp)
>> +{
>> + struct fsi_gpio_msg msg;
>> + uint8_t id, tag;
>> + uint32_t crc;
>> + int i;
>> +
>> + /* wait for the start bit */
>> + for (i = 0; i < FSI_GPIO_MTOE_COUNT; i++) {
>> + msg.bits = 0;
>> + msg.msg = 0;
>> + serial_in(master, &msg, 1);
>> + if (msg.msg)
>> + break;
>> + }
>> + if (i >= FSI_GPIO_MTOE_COUNT) {
>> + dev_dbg(master->dev,
>> + "Master time out waiting for response\n");
>> + fsi_master_gpio_error(master, FSI_GPIO_MTOE);
>> + return -EIO;
>> + }
>> +
>> + msg.bits = 0;
>> + msg.msg = 0;
>> +
>> + /* Read slave ID & response tag */
>> + serial_in(master, &msg, 4);
>> +
>> + id = (msg.msg >> FSI_GPIO_MSG_RESPID_SIZE) & 0x3;
>> + tag = msg.msg & 0x3;
>> +
>> + /* if we have an ACK, and we're expecting data, clock the
>> + * data in too
>> + */
>> + if (tag == FSI_GPIO_RESP_ACK && data_size)
>> + serial_in(master, &msg, data_size * 8);
>> +
>> + /* read CRC */
>> + serial_in(master, &msg, FSI_GPIO_CRC_SIZE);
>> +
>> + /* we have a whole message now; check CRC */
>> + crc = fsi_crc4(0, 1, 1);
>> + crc = fsi_crc4(crc, msg.msg, msg.bits);
>> + if (crc) {
>> + dev_dbg(master->dev, "ERR response CRC\n");
>> + fsi_master_gpio_error(master, FSI_GPIO_CRC_INVAL);
>> + return -EIO;
>> + }
>> +
>> + if (msgp)
>> + *msgp = msg;
>> + if (tagp)
>> + *tagp = tag;
>> +
>> + return 0;
>> +}
>> +
>> +static int issue_term(struct fsi_master_gpio *master, uint8_t slave)
>> +{
>> + struct fsi_gpio_msg cmd;
>> + uint8_t tag;
>> + int rc;
>> +
>> + build_term_command(&cmd, slave);
>> + serial_out(master, &cmd);
>> + echo_delay(master);
>> +
>> + rc = read_one_response(master, 0, NULL, &tag);
>> + if (rc) {
>> + dev_err(master->dev,
>> + "TERM failed; lost communication with slave\n");
>> + return -EIO;
>> + } else if (tag != FSI_GPIO_RESP_ACK) {
>> + dev_err(master->dev, "TERM failed; response %d\n", tag);
>> + return -EIO;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int poll_for_response(struct fsi_master_gpio *master,
>> + uint8_t slave, uint8_t size, void *data)
>> +{
>> + struct fsi_gpio_msg response, cmd;
>> + int busy_count = 0, rc, i;
>> + uint8_t tag;
>> +
>> +retry:
>> + rc = read_one_response(master, size, &response, &tag);
>> + if (rc)
>> + return rc;
>> +
>> + switch (tag) {
>> + case FSI_GPIO_RESP_ACK:
>> + if (size && data) {
>> + uint64_t val = response.msg;
>> + /* clear crc & mask */
>> + val >>= 4;
>> + val &= (1ull << (size * 8)) - 1;
>> +
>> + for (i = 0; i < size; i++) {
>> + ((uint8_t *)data)[size-i-1] =
>> + val & 0xff;
>> + val >>= 8;
>> + }
>> + }
>> + break;
>> + case FSI_GPIO_RESP_BUSY:
>> + /*
>> + * Its necessary to clock slave before issuing
>> + * d-poll, not indicated in the hardware protocol
>> + * spec. < 20 clocks causes slave to hang, 21 ok.
>> + */
>> + clock_zeros(master, FSI_GPIO_DPOLL_CLOCKS);
>> + if (busy_count++ < FSI_GPIO_MAX_BUSY) {
>> + build_dpoll_command(&cmd, slave);
>> + serial_out(master, &cmd);
>> + echo_delay(master);
>> + goto retry;
>> + }
>> + dev_warn(master->dev,
>> + "ERR slave is stuck in busy state, issuing TERM\n");
>> + issue_term(master, slave);
>> + rc = -EIO;
>> + break;
>> +
>> + case FSI_GPIO_RESP_ERRA:
>> + case FSI_GPIO_RESP_ERRC:
>> + dev_dbg(master->dev, "ERR%c received: 0x%x\n",
>> + tag == FSI_GPIO_RESP_ERRA ? 'A' : 'C',
>> + (int)response.msg);
>> + fsi_master_gpio_error(master, response.msg);
>> + rc = -EIO;
>> + break;
>> + }
>> +
>> + /* Clock the slave enough to be ready for next operation */
>> + clock_zeros(master, FSI_GPIO_PRIME_SLAVE_CLOCKS);
>> + return rc;
>> +}
>> +
>> +static int fsi_master_gpio_xfer(struct fsi_master_gpio *master, uint8_t slave,
>> + struct fsi_gpio_msg *cmd, size_t resp_len, void *resp)
>> +{
>> + unsigned long flags;
>> + int rc;
>> +
>> + spin_lock_irqsave(&fsi_gpio_cmd_lock, flags);
>> + serial_out(master, cmd);
>> + echo_delay(master);
>> + rc = poll_for_response(master, slave, resp_len, resp);
>> + spin_unlock_irqrestore(&fsi_gpio_cmd_lock, flags);
>> +
>> + return rc;
>> +}
>> +
>> +static int fsi_master_gpio_read(struct fsi_master *_master, int link,
>> + uint8_t id, uint32_t addr, void *val, size_t size)
>> +{
>> + struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
>> + struct fsi_gpio_msg cmd;
>> +
>> + if (link != 0)
>> + return -ENODEV;
>> +
>> + build_abs_ar_command(&cmd, id, addr, size, NULL);
>> + return fsi_master_gpio_xfer(master, id, &cmd, size, val);
>> +}
>> +
>> +static int fsi_master_gpio_write(struct fsi_master *_master, int link,
>> + uint8_t id, uint32_t addr, const void *val, size_t size)
>> +{
>> + struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
>> + struct fsi_gpio_msg cmd;
>> +
>> + if (link != 0)
>> + return -ENODEV;
>> +
>> + build_abs_ar_command(&cmd, id, addr, size, val);
>> + return fsi_master_gpio_xfer(master, id, &cmd, 0, NULL);
>> +}
>> +
>> +static int fsi_master_gpio_term(struct fsi_master *_master,
>> + int link, uint8_t id)
>> +{
>> + struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
>> + struct fsi_gpio_msg cmd;
>> +
>> + if (link != 0)
>> + return -ENODEV;
>> +
>> + build_term_command(&cmd, id);
>> + return fsi_master_gpio_xfer(master, id, &cmd, 0, NULL);
>> +}
>> +
>> +/*
>> + * Issue a break command on link
>> + */
>> +static int fsi_master_gpio_break(struct fsi_master *_master, int link)
>> +{
>> + struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
>> +
>> + if (link != 0)
>> + return -ENODEV;
>> +
>> + set_sda_output(master, 1);
>> + sda_out(master, 1);
>> + clock_toggle(master, FSI_PRE_BREAK_CLOCKS);
>> + sda_out(master, 0);
>> + clock_toggle(master, FSI_BREAK_CLOCKS);
>> + echo_delay(master);
>> + sda_out(master, 1);
>> + clock_toggle(master, FSI_POST_BREAK_CLOCKS);
>> +
>> + /* Wait for logic reset to take effect */
>> + udelay(200);
>> +
>> + return 0;
>> +}
>> +
>> +static void fsi_master_gpio_init(struct fsi_master_gpio *master)
>> +{
>> + if (master->gpio_mux)
>> + gpiod_direction_output(master->gpio_mux, 1);
>> + if (master->gpio_trans)
>> + gpiod_direction_output(master->gpio_trans, 1);
>> + if (master->gpio_enable)
>> + gpiod_direction_output(master->gpio_enable, 1);
>> + gpiod_direction_output(master->gpio_clk, 1);
>> + gpiod_direction_output(master->gpio_data, 1);
>> +
>> + /* todo: evaluate if clocks can be reduced */
>> + clock_zeros(master, FSI_INIT_CLOCKS);
>> +}
>> +
>> +static int fsi_master_gpio_link_enable(struct fsi_master *_master, int link)
>> +{
>> + struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
>> +
>> + if (link != 0)
>> + return -ENODEV;
>> + if (master->gpio_enable)
>> + gpiod_set_value(master->gpio_enable, 1);
>> +
>> + return 0;
>> +}
>> +
>> +static void fsi_master_gpio_release(struct device *dev)
>> +{
>> + struct fsi_master_gpio *master = to_fsi_master_gpio(
>> + dev_to_fsi_master(dev));
>> +
>> + kfree(master);
>> +}
>> +
>> +static int fsi_master_gpio_probe(struct platform_device *pdev)
>> +{
>> + struct fsi_master_gpio *master;
>> + struct gpio_desc *gpio;
>> +
>> + master = devm_kzalloc(&pdev->dev, sizeof(*master), GFP_KERNEL);
>> + if (!master)
>> + return -ENOMEM;
>> +
>> + master->dev = &pdev->dev;
>> + master->master.dev.parent = master->dev;
>> + master->master.dev.release = fsi_master_gpio_release;
>> +
>> + gpio = devm_gpiod_get(&pdev->dev, "clock", 0);
>> + if (IS_ERR(gpio)) {
>> + dev_err(&pdev->dev, "failed to get clock gpio\n");
>> + return PTR_ERR(gpio);
>> + }
>> + master->gpio_clk = gpio;
>> +
>> + gpio = devm_gpiod_get(&pdev->dev, "data", 0);
>> + if (IS_ERR(gpio)) {
>> + dev_err(&pdev->dev, "failed to get data gpio\n");
>> + return PTR_ERR(gpio);
>> + }
>> + master->gpio_data = gpio;
>> +
>> + /* Optional GPIOs */
>> + gpio = devm_gpiod_get_optional(&pdev->dev, "trans", 0);
>> + if (IS_ERR(gpio)) {
>> + dev_err(&pdev->dev, "failed to get trans gpio\n");
>> + return PTR_ERR(gpio);
>> + }
>> + master->gpio_trans = gpio;
>> +
>> + gpio = devm_gpiod_get_optional(&pdev->dev, "enable", 0);
>> + if (IS_ERR(gpio)) {
>> + dev_err(&pdev->dev, "failed to get enable gpio\n");
>> + return PTR_ERR(gpio);
>> + }
>> + master->gpio_enable = gpio;
>> +
>> + gpio = devm_gpiod_get_optional(&pdev->dev, "mux", 0);
>> + if (IS_ERR(gpio)) {
>> + dev_err(&pdev->dev, "failed to get mux gpio\n");
>> + return PTR_ERR(gpio);
>> + }
>> + master->gpio_mux = gpio;
>> +
>> + master->master.n_links = 1;
>> + master->master.read = fsi_master_gpio_read;
>> + master->master.write = fsi_master_gpio_write;
>> + master->master.term = fsi_master_gpio_term;
>> + master->master.send_break = fsi_master_gpio_break;
>> + master->master.link_enable = fsi_master_gpio_link_enable;
>> + platform_set_drvdata(pdev, master);
>> +
>> + fsi_master_gpio_init(master);
>> +
>> + fsi_master_register(&master->master);
>> +
>> + return 0;
>> +}
>> +
>> +
>> +static int fsi_master_gpio_remove(struct platform_device *pdev)
>> +{
>> + struct fsi_master_gpio *master = platform_get_drvdata(pdev);
>> +
>> + devm_gpiod_put(&pdev->dev, master->gpio_clk);
>> + devm_gpiod_put(&pdev->dev, master->gpio_data);
>> + if (master->gpio_trans)
>> + devm_gpiod_put(&pdev->dev, master->gpio_trans);
>> + if (master->gpio_enable)
>> + devm_gpiod_put(&pdev->dev, master->gpio_enable);
>> + if (master->gpio_mux)
>> + devm_gpiod_put(&pdev->dev, master->gpio_mux);
>> + fsi_master_unregister(&master->master);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id fsi_master_gpio_match[] = {
>> + { .compatible = "fsi-master-gpio" },
>> + { },
>> +};
>> +
>> +static struct platform_driver fsi_master_gpio_driver = {
>> + .driver = {
>> + .name = "fsi-master-gpio",
>> + .of_match_table = fsi_master_gpio_match,
>> + },
>> + .probe = fsi_master_gpio_probe,
>> + .remove = fsi_master_gpio_remove,
>> +};
>> +
>> +module_platform_driver(fsi_master_gpio_driver);
>> +MODULE_LICENSE("GPL");
>> --
>> 1.8.2.2
>>
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