From: Alexandru Tachici <alexandru.tach...@analog.com>

Adm1266 exposes 9 GPIOs and 16 PDIOs which are currently read-only. They
are controlled by the internal sequencing engine.

This patch makes adm1266 driver expose GPIOs and PDIOs to user-space
using GPIO provider kernel api.

Signed-off-by: Alexandru Tachici <alexandru.tach...@analog.com>
---
 drivers/hwmon/pmbus/adm1266.c | 233 +++++++++++++++++++++++++++++++++-
 1 file changed, 232 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c
index 381d89a8569f..76bf2c78e737 100644
--- a/drivers/hwmon/pmbus/adm1266.c
+++ b/drivers/hwmon/pmbus/adm1266.c
@@ -6,8 +6,12 @@
  * Copyright 2020 Analog Devices Inc.
  */
 
+#include <linux/bitfield.h>
 #include <linux/crc8.h>
+#include <linux/debugfs.h>
+#include <linux/gpio/driver.h>
 #include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -15,10 +19,35 @@
 
 #include "pmbus.h"
 
+#define ADM1266_PDIO_CONFIG    0xD4
+#define ADM1266_GPIO_CONFIG    0xE1
+#define ADM1266_PDIO_STATUS    0xE9
+#define ADM1266_GPIO_STATUS    0xEA
+
+/* ADM1266 GPIO defines */
+#define ADM1266_GPIO_NR                        9
+#define ADM1266_GPIO_FUNCTIONS(x)      FIELD_GET(BIT(0), x)
+#define ADM1266_GPIO_INPUT_EN(x)       FIELD_GET(BIT(2), x)
+#define ADM1266_GPIO_OUTPUT_EN(x)      FIELD_GET(BIT(3), x)
+#define ADM1266_GPIO_OPEN_DRAIN(x)     FIELD_GET(BIT(4), x)
+
+/* ADM1266 PDIO defines */
+#define ADM1266_PDIO_NR                        16
+#define ADM1266_PDIO_PIN_CFG(x)                FIELD_GET(GENMASK(15, 13), x)
+#define ADM1266_PDIO_GLITCH_FILT(x)    FIELD_GET(GENMASK(12, 9), x)
+#define ADM1266_PDIO_OUT_CFG(x)                FIELD_GET(GENMASK(2, 0), x)
+
 #define ADM1266_PMBUS_BLOCK_MAX                255
 
 DECLARE_CRC8_TABLE(pmbus_crc_table);
 
+struct adm1266_data {
+       struct pmbus_driver_info info;
+       struct gpio_chip gc;
+       const char *gpio_names[ADM1266_GPIO_NR + ADM1266_PDIO_NR];
+       struct i2c_client *client;
+};
+
 /* Different from Block Read as it sends data and waits for the slave to
  * return a value dependent on that data. The protocol is simply a Write Block
  * followed by a Read Block without the Read-Block command field and the
@@ -91,18 +120,220 @@ int pmbus_block_xfer(struct i2c_client *client, u8 cmd, 
u8 w_len,
        return ret;
 }
 
+#ifdef CONFIG_GPIOLIB
+static const unsigned int adm1266_gpio_mapping[ADM1266_GPIO_NR][2] = {
+       {1, 0},
+       {2, 1},
+       {3, 2},
+       {4, 8},
+       {5, 9},
+       {6, 10},
+       {7, 11},
+       {8, 6},
+       {9, 7},
+};
+
+static const char *adm1266_names[ADM1266_GPIO_NR + ADM1266_PDIO_NR] = {
+       "GPIO1", "GPIO2", "GPIO3", "GPIO4", "GPIO5", "GPIO6", "GPIO7", "GPIO8",
+       "GPIO9", "PDIO1", "PDIO2", "PDIO3", "PDIO4", "PDIO5", "PDIO6",
+       "PDIO7", "PDIO8", "PDIO9", "PDIO10", "PDIO11", "PDIO12", "PDIO13",
+       "PDIO14", "PDIO15", "PDIO16",
+};
+
+static int adm1266_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+       struct adm1266_data *data = gpiochip_get_data(chip);
+       u8 read_buf[I2C_SMBUS_BLOCK_MAX + 1];
+       unsigned long pins_status;
+       unsigned int pmbus_cmd;
+       int ret;
+
+       if (offset < ADM1266_GPIO_NR)
+               pmbus_cmd = ADM1266_GPIO_STATUS;
+       else
+               pmbus_cmd = ADM1266_PDIO_STATUS;
+
+       ret = i2c_smbus_read_block_data(data->client, pmbus_cmd,
+                                       read_buf);
+       if (ret < 0)
+               return ret;
+
+       pins_status = read_buf[0] + (read_buf[1] << 8);
+       if (offset < ADM1266_GPIO_NR)
+               return test_bit(adm1266_gpio_mapping[offset][1], &pins_status);
+
+       return test_bit(offset - ADM1266_GPIO_NR, &pins_status);
+}
+
+static int adm1266_gpio_get_multiple(struct gpio_chip *chip,
+                                    unsigned long *mask,
+                                    unsigned long *bits)
+{
+       struct adm1266_data *data = gpiochip_get_data(chip);
+       u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1];
+       unsigned long status;
+       unsigned int gpio_nr;
+       int ret;
+
+       ret = i2c_smbus_read_block_data(data->client, ADM1266_GPIO_STATUS,
+                                       read_buf);
+       if (ret < 0)
+               return ret;
+
+       status = read_buf[0] + (read_buf[1] << 8);
+
+       *bits = 0;
+       for_each_set_bit(gpio_nr, mask, ADM1266_GPIO_NR) {
+               if (test_bit(adm1266_gpio_mapping[gpio_nr][1], &status))
+                       set_bit(gpio_nr, bits);
+       }
+
+       ret = i2c_smbus_read_block_data(data->client, ADM1266_PDIO_STATUS,
+                                       read_buf);
+       if (ret < 0)
+               return ret;
+
+       status = read_buf[0] + (read_buf[1] << 8);
+
+       *bits = 0;
+       for_each_set_bit_from(gpio_nr, mask,
+                             ADM1266_GPIO_NR + ADM1266_PDIO_STATUS) {
+               if (test_bit(gpio_nr - ADM1266_GPIO_NR, &status))
+                       set_bit(gpio_nr, bits);
+       }
+
+       return 0;
+}
+
+static void adm1266_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
+{
+       struct adm1266_data *data = gpiochip_get_data(chip);
+       u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1];
+       unsigned long gpio_config;
+       unsigned long pdio_config;
+       unsigned long pin_cfg;
+       u8 write_cmd;
+       int ret;
+       int i;
+
+       for (i = 0; i < ADM1266_GPIO_NR; i++) {
+               write_cmd = adm1266_gpio_mapping[i][1];
+               ret = pmbus_block_xfer(data->client, ADM1266_GPIO_CONFIG, 1,
+                                      &write_cmd, read_buf);
+               if (ret != 2)
+                       return;
+
+               gpio_config = read_buf[0];
+               seq_puts(s, adm1266_names[i]);
+
+               seq_puts(s, " ( ");
+               if (!ADM1266_GPIO_FUNCTIONS(gpio_config)) {
+                       seq_puts(s, "high-Z )\n");
+                       continue;
+               }
+               if (ADM1266_GPIO_INPUT_EN(gpio_config))
+                       seq_puts(s, "input ");
+               if (ADM1266_GPIO_OUTPUT_EN(gpio_config))
+                       seq_puts(s, "output ");
+               if (ADM1266_GPIO_OPEN_DRAIN(gpio_config))
+                       seq_puts(s, "open-drain )\n");
+               else
+                       seq_puts(s, "push-pull )\n");
+       }
+
+       write_cmd = 0xFF;
+       ret = pmbus_block_xfer(data->client, ADM1266_PDIO_CONFIG, 1, &write_cmd,
+                              read_buf);
+       if (ret != 32)
+               return;
+
+       for (i = 0; i < ADM1266_PDIO_NR; i++) {
+               seq_puts(s, adm1266_names[ADM1266_GPIO_NR + i]);
+
+               pdio_config = read_buf[2 * i];
+               pdio_config += (read_buf[2 * i + 1] << 8);
+               pin_cfg = ADM1266_PDIO_PIN_CFG(pdio_config);
+
+               seq_puts(s, " ( ");
+               if (!pin_cfg || pin_cfg > 5) {
+                       seq_puts(s, "high-Z )\n");
+                       continue;
+               }
+
+               if (pin_cfg & BIT(0))
+                       seq_puts(s, "output ");
+
+               if (pin_cfg & BIT(1))
+                       seq_puts(s, "input ");
+
+               seq_puts(s, ")\n");
+       }
+}
+
+static int adm1266_config_gpio(struct adm1266_data *data)
+{
+       const char *name = dev_name(&data->client->dev);
+       char *gpio_name;
+       int ret;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(data->gpio_names); i++) {
+               gpio_name = devm_kasprintf(&data->client->dev, GFP_KERNEL,
+                                          "adm1266-%x-%s", data->client->addr,
+                                          adm1266_names[i]);
+               if (!gpio_name)
+                       return -ENOMEM;
+
+               data->gpio_names[i] = gpio_name;
+       }
+
+       data->gc.label = name;
+       data->gc.parent = &data->client->dev;
+       data->gc.owner = THIS_MODULE;
+       data->gc.base = -1;
+       data->gc.names = data->gpio_names;
+       data->gc.ngpio = ARRAY_SIZE(data->gpio_names);
+       data->gc.get = adm1266_gpio_get;
+       data->gc.get_multiple = adm1266_gpio_get_multiple;
+       data->gc.dbg_show = adm1266_gpio_dbg_show;
+
+       ret = devm_gpiochip_add_data(&data->client->dev, &data->gc, data);
+       if (ret)
+               dev_err(&data->client->dev, "GPIO registering failed (%d)\n",
+                       ret);
+
+       return ret;
+}
+#else
+static int adm1266_config_gpio(struct adm1266_data *data)
+{
+       return 0;
+}
+#endif
+
 static int adm1266_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
 {
        struct pmbus_driver_info *info;
+       struct adm1266_data *data;
        u32 funcs;
+       int ret;
        int i;
 
-       info = devm_kzalloc(&client->dev, sizeof(struct pmbus_driver_info),
+       data = devm_kzalloc(&client->dev, sizeof(struct adm1266_data),
                            GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       data->client = client;
+
+       ret = adm1266_config_gpio(data);
+       if (ret < 0)
+               return ret;
 
        crc8_populate_msb(pmbus_crc_table, 0x7);
 
+       info = &data->info;
        info->pages = 17;
        info->format[PSC_VOLTAGE_OUT] = linear;
        funcs = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT;
-- 
2.20.1

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