serial: max310x: use common detect function for all variants

Simplify driver by defining a common function to handle the detection
of all variants.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-14-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index c93b326faf89bb554da4156d01bf7508a2f48da9..83beaab3a0c57ed3be2e51262a684c6429e5c249 100644 (file)
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -67,6 +67,7 @@
 #define MAX310X_BRGDIVMSB_REG          (0x1d) /* Baud rate divisor MSB */
 #define MAX310X_CLKSRC_REG             (0x1e) /* Clock source */
 #define MAX310X_REG_1F                 (0x1f)
+#define MAX310X_EXTREG_START           (0x20) /* Only relevant in SPI mode. */
 
 #define MAX310X_REVID_REG              MAX310X_REG_1F /* Revision ID */
 
@@ -74,9 +75,9 @@
 #define MAX310X_GLOBALCMD_REG          MAX310X_REG_1F /* Global Command (WO) */
 
 /* Extended registers */
-#define MAX310X_SPI_REVID_EXTREG       MAX310X_REG_05 /* Revision ID */
-#define MAX310X_I2C_REVID_EXTREG       (0x25) /* Revision ID */
-
+#define MAX310X_REVID_EXTREG           (0x25) /* Revision ID
+                                               * (extended addressing space)
+                                               */
 /* IRQ register bits */
 #define MAX310X_IRQ_LSR_BIT            (1 << 0) /* LSR interrupt */
 #define MAX310X_IRQ_SPCHR_BIT          (1 << 1) /* Special char interrupt */
@@ -250,8 +251,7 @@
 
 struct max310x_if_cfg {
        int (*extended_reg_enable)(struct device *dev, bool enable);
-
-       unsigned int rev_id_reg;
+       u8 rev_id_offset;
 };
 
 struct max310x_devtype {
@@ -260,10 +260,11 @@ struct max310x_devtype {
                unsigned short max;
        } slave_addr;
        int     nr;
-       int     (*detect)(struct device *);
        void    (*power)(struct uart_port *, int);
        char    name[9];
        u8      mode1;
+       u8      rev_id_val;
+       u8      rev_id_reg; /* Relevant only if rev_id_val is defined. */
 };
 
 struct max310x_one {
@@ -324,62 +325,52 @@ static void max310x_port_update(struct uart_port *port, u8 reg, u8 mask, u8 val)
        regmap_update_bits(one->regmap, reg, mask, val);
 }
 
-static int max3107_detect(struct device *dev)
+static int max310x_detect(struct device *dev)
 {
        struct max310x_port *s = dev_get_drvdata(dev);
        unsigned int val = 0;
        int ret;
 
-       ret = regmap_read(s->regmap, MAX310X_REVID_REG, &val);
-       if (ret)
-               return ret;
-
-       if (((val & MAX310x_REV_MASK) != MAX3107_REV_ID)) {
-               dev_err(dev,
-                       "%s ID 0x%02x does not match\n", s->devtype->name, val);
-               return -ENODEV;
-       }
+       /* Check if variant supports REV ID register: */
+       if (s->devtype->rev_id_val) {
+               u8 rev_id_reg = s->devtype->rev_id_reg;
 
-       return 0;
-}
+               /* Check if REV ID is in extended addressing space: */
+               if (s->devtype->rev_id_reg >= MAX310X_EXTREG_START) {
+                       ret = s->if_cfg->extended_reg_enable(dev, true);
+                       if (ret)
+                               return ret;
 
-static int max3108_detect(struct device *dev)
-{
-       struct max310x_port *s = dev_get_drvdata(dev);
-       unsigned int val = 0;
-       int ret;
-
-       /* MAX3108 have not REV ID register, we just check default value
-        * from clocksource register to make sure everything works.
-        */
-       ret = regmap_read(s->regmap, MAX310X_CLKSRC_REG, &val);
-       if (ret)
-               return ret;
-
-       if (val != (MAX310X_CLKSRC_EXTCLK_BIT | MAX310X_CLKSRC_PLLBYP_BIT)) {
-               dev_err(dev, "%s not present\n", s->devtype->name);
-               return -ENODEV;
-       }
+                       /* Adjust REV ID extended addressing space address: */
+                       if (s->if_cfg->rev_id_offset)
+                               rev_id_reg -= s->if_cfg->rev_id_offset;
+               }
 
-       return 0;
-}
+               regmap_read(s->regmap, rev_id_reg, &val);
 
-static int max3109_detect(struct device *dev)
-{
-       struct max310x_port *s = dev_get_drvdata(dev);
-       unsigned int val = 0;
-       int ret;
+               if (s->devtype->rev_id_reg >= MAX310X_EXTREG_START) {
+                       ret = s->if_cfg->extended_reg_enable(dev, false);
+                       if (ret)
+                               return ret;
+               }
 
-       ret = s->if_cfg->extended_reg_enable(dev, true);
-       if (ret)
-               return ret;
+               if (((val & MAX310x_REV_MASK) != s->devtype->rev_id_val))
+                       return dev_err_probe(dev, -ENODEV,
+                                            "%s ID 0x%02x does not match\n",
+                                            s->devtype->name, val);
+       } else {
+               /*
+                * For variant without REV ID register, just check default value
+                * from clocksource register to make sure everything works.
+                */
+               ret = regmap_read(s->regmap, MAX310X_CLKSRC_REG, &val);
+               if (ret)
+                       return ret;
 
-       regmap_read(s->regmap, s->if_cfg->rev_id_reg, &val);
-       s->if_cfg->extended_reg_enable(dev, false);
-       if (((val & MAX310x_REV_MASK) != MAX3109_REV_ID)) {
-               dev_err(dev,
-                       "%s ID 0x%02x does not match\n", s->devtype->name, val);
-               return -ENODEV;
+               if (val != (MAX310X_CLKSRC_EXTCLK_BIT | MAX310X_CLKSRC_PLLBYP_BIT))
+                       return dev_err_probe(dev, -ENODEV,
+                                            "%s not present\n",
+                                            s->devtype->name);
        }
 
        return 0;
@@ -394,27 +385,6 @@ static void max310x_power(struct uart_port *port, int on)
                msleep(50);
 }
 
-static int max14830_detect(struct device *dev)
-{
-       struct max310x_port *s = dev_get_drvdata(dev);
-       unsigned int val = 0;
-       int ret;
-
-       ret = s->if_cfg->extended_reg_enable(dev, true);
-       if (ret)
-               return ret;
-
-       regmap_read(s->regmap, s->if_cfg->rev_id_reg, &val);
-       s->if_cfg->extended_reg_enable(dev, false);
-       if (((val & MAX310x_REV_MASK) != MAX14830_REV_ID)) {
-               dev_err(dev,
-                       "%s ID 0x%02x does not match\n", s->devtype->name, val);
-               return -ENODEV;
-       }
-
-       return 0;
-}
-
 static void max14830_power(struct uart_port *port, int on)
 {
        max310x_port_update(port, MAX310X_BRGCFG_REG,
@@ -428,7 +398,8 @@ static const struct max310x_devtype max3107_devtype = {
        .name   = "MAX3107",
        .nr     = 1,
        .mode1  = MAX310X_MODE1_AUTOSLEEP_BIT | MAX310X_MODE1_IRQSEL_BIT,
-       .detect = max3107_detect,
+       .rev_id_val = MAX3107_REV_ID,
+       .rev_id_reg = MAX310X_REVID_REG,
        .power  = max310x_power,
        .slave_addr     = {
                .min = 0x2c,
@@ -440,7 +411,8 @@ static const struct max310x_devtype max3108_devtype = {
        .name   = "MAX3108",
        .nr     = 1,
        .mode1  = MAX310X_MODE1_AUTOSLEEP_BIT,
-       .detect = max3108_detect,
+       .rev_id_val = 0, /* Unsupported. */
+       .rev_id_reg = 0, /* Irrelevant when rev_id_val is not defined. */
        .power  = max310x_power,
        .slave_addr     = {
                .min = 0x60,
@@ -452,7 +424,8 @@ static const struct max310x_devtype max3109_devtype = {
        .name   = "MAX3109",
        .nr     = 2,
        .mode1  = MAX310X_MODE1_AUTOSLEEP_BIT,
-       .detect = max3109_detect,
+       .rev_id_val = MAX3109_REV_ID,
+       .rev_id_reg = MAX310X_REVID_EXTREG,
        .power  = max310x_power,
        .slave_addr     = {
                .min = 0x60,
@@ -464,7 +437,8 @@ static const struct max310x_devtype max14830_devtype = {
        .name   = "MAX14830",
        .nr     = 4,
        .mode1  = MAX310X_MODE1_IRQSEL_BIT,
-       .detect = max14830_detect,
+       .rev_id_val = MAX14830_REV_ID,
+       .rev_id_reg = MAX310X_REVID_EXTREG,
        .power  = max14830_power,
        .slave_addr     = {
                .min = 0x60,
@@ -1322,7 +1296,7 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty
        dev_set_drvdata(dev, s);
 
        /* Check device to ensure we are talking to what we expect */
-       ret = devtype->detect(dev);
+       ret = max310x_detect(dev);
        if (ret)
                goto out_clk;
 
@@ -1501,7 +1475,7 @@ static int max310x_spi_extended_reg_enable(struct device *dev, bool enable)
 
 static const struct max310x_if_cfg __maybe_unused max310x_spi_if_cfg = {
        .extended_reg_enable = max310x_spi_extended_reg_enable,
-       .rev_id_reg = MAX310X_SPI_REVID_EXTREG,
+       .rev_id_offset = MAX310X_EXTREG_START,
 };
 
 static int max310x_spi_probe(struct spi_device *spi)
@@ -1574,7 +1548,7 @@ static struct regmap_config regcfg_i2c = {
        .writeable_reg = max310x_reg_writeable,
        .volatile_reg = max310x_reg_volatile,
        .precious_reg = max310x_reg_precious,
-       .max_register = MAX310X_I2C_REVID_EXTREG,
+       .max_register = MAX310X_REVID_EXTREG,
        .writeable_noinc_reg = max310x_reg_noinc,
        .readable_noinc_reg = max310x_reg_noinc,
        .max_raw_read = MAX310X_FIFO_SIZE,
@@ -1583,7 +1557,7 @@ static struct regmap_config regcfg_i2c = {
 
 static const struct max310x_if_cfg max310x_i2c_if_cfg = {
        .extended_reg_enable = max310x_i2c_extended_reg_enable,
-       .rev_id_reg = MAX310X_I2C_REVID_EXTREG,
+       .rev_id_offset = 0, /* No offset in I2C mode. */
 };
 
 static unsigned short max310x_i2c_slave_addr(unsigned short addr,