[PATCH 3/4] counter: 104-quad-8: Implement and utilize register structures

From: William Breathitt Gray
Date: Thu Jul 14 2022 - 12:14:29 EST

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Reduce magic numbers and improve code readability by implementing and
utilizing named register data structures.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Tested-by: Fred Eckert <Frede@xxxxxxxxxxxx>
Cc: Syed Nayyar Waris <syednwaris@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220707171709.36010-1-william.gray@xxxxxxxxxx/
Signed-off-by: William Breathitt Gray <william.gray@xxxxxxxxxx>
---
drivers/counter/104-quad-8.c | 166 ++++++++++++++++++++---------------
1 file changed, 93 insertions(+), 73 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 43dde9abfdcf..62c2b7ac4339 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -33,6 +33,36 @@ MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");

#define QUAD8_NUM_COUNTERS 8

+/**
+ * struct channel_reg - channel register structure
+ * @data: Count data
+ * @control: Channel flags and control
+ */
+struct channel_reg {
+ u8 data;
+ u8 control;
+};
+
+/**
+ * struct quad8_reg - device register structure
+ * @channel: quadrature counter data and control
+ * @interrupt_status: channel interrupt status
+ * @channel_oper: enable/reset counters and interrupt functions
+ * @index_interrupt: enable channel interrupts
+ * @reserved: reserved for Factory Use
+ * @index_input_levels: index signal logical input level
+ * @cable_status: differential encoder cable status
+ */
+struct quad8_reg {
+ struct channel_reg channel[QUAD8_NUM_COUNTERS];
+ u8 interrupt_status;
+ u8 channel_oper;
+ u8 index_interrupt;
+ u8 reserved[3];
+ u8 index_input_levels;
+ u8 cable_status;
+};
+
/**
* struct quad8 - device private data structure
* @lock: lock to prevent clobbering device states during R/W ops
@@ -48,7 +78,7 @@ MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
* @synchronous_mode: array of index function synchronous mode configurations
* @index_polarity: array of index function polarity configurations
* @cable_fault_enable: differential encoder cable status enable configurations
- * @base: base port address of the device
+ * @reg: I/O address offset for the device registers
*/
struct quad8 {
spinlock_t lock;
@@ -63,14 +93,9 @@ struct quad8 {
unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
unsigned int index_polarity[QUAD8_NUM_COUNTERS];
unsigned int cable_fault_enable;
- void __iomem *base;
+ struct quad8_reg __iomem *reg;
};

-#define QUAD8_REG_INTERRUPT_STATUS 0x10
-#define QUAD8_REG_CHAN_OP 0x11
-#define QUAD8_REG_INDEX_INTERRUPT 0x12
-#define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
-#define QUAD8_DIFF_ENCODER_CABLE_STATUS 0x17
/* Borrow Toggle flip-flop */
#define QUAD8_FLAG_BT BIT(0)
/* Carry Toggle flip-flop */
@@ -118,8 +143,7 @@ static int quad8_signal_read(struct counter_device *counter,
if (signal->id < 16)
return -EINVAL;

- state = ioread8(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS) &
- BIT(signal->id - 16);
+ state = ioread8(&priv->reg->index_input_levels) & BIT(signal->id - 16);

*level = (state) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;

@@ -130,14 +154,14 @@ static int quad8_count_read(struct counter_device *counter,
struct counter_count *count, u64 *val)
{
struct quad8 *const priv = counter_priv(counter);
- void __iomem *const base_offset = priv->base + 2 * count->id;
+ struct channel_reg __iomem *const chan = priv->reg->channel + count->id;
unsigned int flags;
unsigned int borrow;
unsigned int carry;
unsigned long irqflags;
int i;

- flags = ioread8(base_offset + 1);
+ flags = ioread8(&chan->control);
borrow = flags & QUAD8_FLAG_BT;
carry = !!(flags & QUAD8_FLAG_CT);

@@ -148,10 +172,10 @@ static int quad8_count_read(struct counter_device *counter,

/* Reset Byte Pointer; transfer Counter to Output Latch */
iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
- base_offset + 1);
+ &chan->control);

for (i = 0; i < 3; i++)
- *val |= (unsigned long)ioread8(base_offset) << (8 * i);
+ *val |= (unsigned long)ioread8(&chan->data) << (8 * i);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -162,7 +186,7 @@ static int quad8_count_write(struct counter_device *counter,
struct counter_count *count, u64 val)
{
struct quad8 *const priv = counter_priv(counter);
- void __iomem *const base_offset = priv->base + 2 * count->id;
+ struct channel_reg __iomem *const chan = priv->reg->channel + count->id;
unsigned long irqflags;
int i;

@@ -173,27 +197,27 @@ static int quad8_count_write(struct counter_device *counter,
spin_lock_irqsave(&priv->lock, irqflags);

/* Reset Byte Pointer */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);

/* Counter can only be set via Preset Register */
for (i = 0; i < 3; i++)
- iowrite8(val >> (8 * i), base_offset);
+ iowrite8(val >> (8 * i), &chan->data);

/* Transfer Preset Register to Counter */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, &chan->control);

/* Reset Byte Pointer */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);

/* Set Preset Register back to original value */
val = priv->preset[count->id];
for (i = 0; i < 3; i++)
- iowrite8(val >> (8 * i), base_offset);
+ iowrite8(val >> (8 * i), &chan->data);

/* Reset Borrow, Carry, Compare, and Sign flags */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, &chan->control);
/* Reset Error flag */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, &chan->control);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -246,7 +270,7 @@ static int quad8_function_write(struct counter_device *counter,
unsigned int *const quadrature_mode = priv->quadrature_mode + id;
unsigned int *const scale = priv->quadrature_scale + id;
unsigned int *const synchronous_mode = priv->synchronous_mode + id;
- void __iomem *const base_offset = priv->base + 2 * id + 1;
+ u8 __iomem *const control = &priv->reg->channel[id].control;
unsigned long irqflags;
unsigned int mode_cfg;
unsigned int idr_cfg;
@@ -266,7 +290,7 @@ static int quad8_function_write(struct counter_device *counter,
if (*synchronous_mode) {
*synchronous_mode = 0;
/* Disable synchronous function mode */
- iowrite8(QUAD8_CTR_IDR | idr_cfg, base_offset);
+ iowrite8(QUAD8_CTR_IDR | idr_cfg, control);
}
} else {
*quadrature_mode = 1;
@@ -292,7 +316,7 @@ static int quad8_function_write(struct counter_device *counter,
}

/* Load mode configuration to Counter Mode Register */
- iowrite8(QUAD8_CTR_CMR | mode_cfg, base_offset);
+ iowrite8(QUAD8_CTR_CMR | mode_cfg, control);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -305,7 +329,7 @@ static int quad8_direction_read(struct counter_device *counter,
{
const struct quad8 *const priv = counter_priv(counter);
unsigned int ud_flag;
- void __iomem *const flag_addr = priv->base + 2 * count->id + 1;
+ u8 __iomem *const flag_addr = &priv->reg->channel[count->id].control;

/* U/D flag: nonzero = up, zero = down */
ud_flag = ioread8(flag_addr) & QUAD8_FLAG_UD;
@@ -402,7 +426,6 @@ static int quad8_events_configure(struct counter_device *counter)
struct counter_event_node *event_node;
unsigned int next_irq_trigger;
unsigned long ior_cfg;
- void __iomem *base_offset;

spin_lock_irqsave(&priv->lock, irqflags);

@@ -437,14 +460,14 @@ static int quad8_events_configure(struct counter_device *counter)
ior_cfg = priv->ab_enable[event_node->channel] |
priv->preset_enable[event_node->channel] << 1 |
priv->irq_trigger[event_node->channel] << 3;
- base_offset = priv->base + 2 * event_node->channel + 1;
- iowrite8(QUAD8_CTR_IOR | ior_cfg, base_offset);
+ iowrite8(QUAD8_CTR_IOR | ior_cfg,
+ &priv->reg->channel[event_node->channel].control);

/* Enable IRQ line */
irq_enabled |= BIT(event_node->channel);
}

- iowrite8(irq_enabled, priv->base + QUAD8_REG_INDEX_INTERRUPT);
+ iowrite8(irq_enabled, &priv->reg->index_interrupt);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -508,7 +531,7 @@ static int quad8_index_polarity_set(struct counter_device *counter,
{
struct quad8 *const priv = counter_priv(counter);
const size_t channel_id = signal->id - 16;
- void __iomem *const base_offset = priv->base + 2 * channel_id + 1;
+ u8 __iomem *const control = &priv->reg->channel[channel_id].control;
unsigned long irqflags;
unsigned int idr_cfg = index_polarity << 1;

@@ -519,7 +542,7 @@ static int quad8_index_polarity_set(struct counter_device *counter,
priv->index_polarity[channel_id] = index_polarity;

/* Load Index Control configuration to Index Control Register */
- iowrite8(QUAD8_CTR_IDR | idr_cfg, base_offset);
+ iowrite8(QUAD8_CTR_IDR | idr_cfg, control);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -549,7 +572,7 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
{
struct quad8 *const priv = counter_priv(counter);
const size_t channel_id = signal->id - 16;
- void __iomem *const base_offset = priv->base + 2 * channel_id + 1;
+ u8 __iomem *const control = &priv->reg->channel[channel_id].control;
unsigned long irqflags;
unsigned int idr_cfg = synchronous_mode;

@@ -566,7 +589,7 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
priv->synchronous_mode[channel_id] = synchronous_mode;

/* Load Index Control configuration to Index Control Register */
- iowrite8(QUAD8_CTR_IDR | idr_cfg, base_offset);
+ iowrite8(QUAD8_CTR_IDR | idr_cfg, control);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -614,7 +637,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
struct quad8 *const priv = counter_priv(counter);
unsigned int count_mode;
unsigned int mode_cfg;
- void __iomem *const base_offset = priv->base + 2 * count->id + 1;
+ u8 __iomem *const control = &priv->reg->channel[count->id].control;
unsigned long irqflags;

/* Map Generic Counter count mode to 104-QUAD-8 count mode */
@@ -648,7 +671,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
mode_cfg |= (priv->quadrature_scale[count->id] + 1) << 3;

/* Load mode configuration to Counter Mode Register */
- iowrite8(QUAD8_CTR_CMR | mode_cfg, base_offset);
+ iowrite8(QUAD8_CTR_CMR | mode_cfg, control);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -669,7 +692,7 @@ static int quad8_count_enable_write(struct counter_device *counter,
struct counter_count *count, u8 enable)
{
struct quad8 *const priv = counter_priv(counter);
- void __iomem *const base_offset = priv->base + 2 * count->id;
+ u8 __iomem *const control = &priv->reg->channel[count->id].control;
unsigned long irqflags;
unsigned int ior_cfg;

@@ -681,7 +704,7 @@ static int quad8_count_enable_write(struct counter_device *counter,
priv->irq_trigger[count->id] << 3;

/* Load I/O control configuration */
- iowrite8(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
+ iowrite8(QUAD8_CTR_IOR | ior_cfg, control);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -697,9 +720,9 @@ static int quad8_error_noise_get(struct counter_device *counter,
struct counter_count *count, u32 *noise_error)
{
const struct quad8 *const priv = counter_priv(counter);
- void __iomem *const base_offset = priv->base + 2 * count->id + 1;
+ u8 __iomem *const flag_addr = &priv->reg->channel[count->id].control;

- *noise_error = !!(ioread8(base_offset) & QUAD8_FLAG_E);
+ *noise_error = !!(ioread8(flag_addr) & QUAD8_FLAG_E);

return 0;
}
@@ -717,17 +740,17 @@ static int quad8_count_preset_read(struct counter_device *counter,
static void quad8_preset_register_set(struct quad8 *const priv, const int id,
const unsigned int preset)
{
- void __iomem *const base_offset = priv->base + 2 * id;
+ struct channel_reg __iomem *const chan = priv->reg->channel + id;
int i;

priv->preset[id] = preset;

/* Reset Byte Pointer */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);

/* Set Preset Register */
for (i = 0; i < 3; i++)
- iowrite8(preset >> (8 * i), base_offset);
+ iowrite8(preset >> (8 * i), &chan->data);
}

static int quad8_count_preset_write(struct counter_device *counter,
@@ -816,7 +839,7 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
u8 preset_enable)
{
struct quad8 *const priv = counter_priv(counter);
- void __iomem *const base_offset = priv->base + 2 * count->id + 1;
+ u8 __iomem *const control = &priv->reg->channel[count->id].control;
unsigned long irqflags;
unsigned int ior_cfg;

@@ -831,7 +854,7 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
priv->irq_trigger[count->id] << 3;

/* Load I/O control configuration to Input / Output Control Register */
- iowrite8(QUAD8_CTR_IOR | ior_cfg, base_offset);
+ iowrite8(QUAD8_CTR_IOR | ior_cfg, control);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -858,7 +881,7 @@ static int quad8_signal_cable_fault_read(struct counter_device *counter,
}

/* Logic 0 = cable fault */
- status = ioread8(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
+ status = ioread8(&priv->reg->cable_status);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -899,8 +922,7 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
/* Enable is active low in Differential Encoder Cable Status register */
cable_fault_enable = ~priv->cable_fault_enable;

- iowrite8(cable_fault_enable,
- priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
+ iowrite8(cable_fault_enable, &priv->reg->cable_status);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -924,7 +946,7 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
{
struct quad8 *const priv = counter_priv(counter);
const size_t channel_id = signal->id / 2;
- void __iomem *const base_offset = priv->base + 2 * channel_id;
+ struct channel_reg __iomem *const chan = priv->reg->channel + channel_id;
unsigned long irqflags;

spin_lock_irqsave(&priv->lock, irqflags);
@@ -932,12 +954,12 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
priv->fck_prescaler[channel_id] = prescaler;

/* Reset Byte Pointer */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);

/* Set filter clock factor */
- iowrite8(prescaler, base_offset);
+ iowrite8(prescaler, &chan->data);
iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
- base_offset + 1);
+ &chan->control);

spin_unlock_irqrestore(&priv->lock, irqflags);

@@ -1085,12 +1107,11 @@ static irqreturn_t quad8_irq_handler(int irq, void *private)
{
struct counter_device *counter = private;
struct quad8 *const priv = counter_priv(counter);
- void __iomem *const base = priv->base;
unsigned long irq_status;
unsigned long channel;
u8 event;

- irq_status = ioread8(base + QUAD8_REG_INTERRUPT_STATUS);
+ irq_status = ioread8(&priv->reg->interrupt_status);
if (!irq_status)
return IRQ_NONE;

@@ -1119,36 +1140,36 @@ static irqreturn_t quad8_irq_handler(int irq, void *private)
}

/* Clear pending interrupts on device */
- iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base + QUAD8_REG_CHAN_OP);
+ iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, &priv->reg->channel_oper);

return IRQ_HANDLED;
}

-static void quad8_init_counter(void __iomem *const base_offset)
+static void quad8_init_counter(struct channel_reg __iomem *const chan)
{
unsigned long i;

/* Reset Byte Pointer */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
/* Reset filter clock factor */
- iowrite8(0, base_offset);
+ iowrite8(0, &chan->data);
iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
- base_offset + 1);
+ &chan->control);
/* Reset Byte Pointer */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, &chan->control);
/* Reset Preset Register */
for (i = 0; i < 3; i++)
- iowrite8(0x00, base_offset);
+ iowrite8(0x00, &chan->data);
/* Reset Borrow, Carry, Compare, and Sign flags */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, &chan->control);
/* Reset Error flag */
- iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
+ iowrite8(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, &chan->control);
/* Binary encoding; Normal count; non-quadrature mode */
- iowrite8(QUAD8_CTR_CMR, base_offset + 1);
+ iowrite8(QUAD8_CTR_CMR, &chan->control);
/* Disable A and B inputs; preset on index; FLG1 as Carry */
- iowrite8(QUAD8_CTR_IOR, base_offset + 1);
+ iowrite8(QUAD8_CTR_IOR, &chan->control);
/* Disable index function; negative index polarity */
- iowrite8(QUAD8_CTR_IDR, base_offset + 1);
+ iowrite8(QUAD8_CTR_IDR, &chan->control);
}

static int quad8_probe(struct device *dev, unsigned int id)
@@ -1169,8 +1190,8 @@ static int quad8_probe(struct device *dev, unsigned int id)
return -ENOMEM;
priv = counter_priv(counter);

- priv->base = devm_ioport_map(dev, base[id], QUAD8_EXTENT);
- if (!priv->base)
+ priv->reg = devm_ioport_map(dev, base[id], QUAD8_EXTENT);
+ if (!priv->reg)
return -ENOMEM;

/* Initialize Counter device and driver data */
@@ -1185,17 +1206,16 @@ static int quad8_probe(struct device *dev, unsigned int id)
spin_lock_init(&priv->lock);

/* Reset Index/Interrupt Register */
- iowrite8(0x00, priv->base + QUAD8_REG_INDEX_INTERRUPT);
+ iowrite8(0x00, &priv->reg->index_interrupt);
/* Reset all counters and disable interrupt function */
- iowrite8(QUAD8_CHAN_OP_RESET_COUNTERS, priv->base + QUAD8_REG_CHAN_OP);
+ iowrite8(QUAD8_CHAN_OP_RESET_COUNTERS, &priv->reg->channel_oper);
/* Set initial configuration for all counters */
for (i = 0; i < QUAD8_NUM_COUNTERS; i++)
- quad8_init_counter(priv->base + 2 * i);
+ quad8_init_counter(priv->reg->channel + i);
/* Disable Differential Encoder Cable Status for all channels */
- iowrite8(0xFF, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
+ iowrite8(0xFF, &priv->reg->cable_status);
/* Enable all counters and enable interrupt function */
- iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC,
- priv->base + QUAD8_REG_CHAN_OP);
+ iowrite8(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, &priv->reg->channel_oper);

err = devm_request_irq(&counter->dev, irq[id], quad8_irq_handler,
IRQF_SHARED, counter->name, counter);
--
2.36.1

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