[PATCH v2 6/7] i2c: npcm: use i2c frequency table

Tyrone Ting
2024-08-30T03:49:11Z

Modify i2c frequency from table parameters
for NPCM i2c modules.

Supported frequencies are:

1. 100KHz
2. 400KHz
3. 1MHz

Signed-off-by: Tyrone Ting <kfting@nuvoton.com>
---
drivers/i2c/busses/i2c-npcm7xx.c | 230 +++++++++++++++++++------------
1 file changed, 144 insertions(+), 86 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 67d156ed29b9..cac4ea0b69b8 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -263,6 +263,121 @@ static const int npcm_i2caddr[I2C_NUM_OWN_ADDR] = {
#define I2C_FREQ_MIN_HZ 10000
#define I2C_FREQ_MAX_HZ I2C_MAX_FAST_MODE_PLUS_FREQ

+struct SMB_TIMING_T {
+ u32 core_clk;
+ u8 hldt;
+ u8 dbcnt;
+ u16 sclfrq;
+ u8 scllt;
+ u8 sclht;
+ bool fast_mode;
+};
+
+static struct SMB_TIMING_T SMB_TIMING_100KHZ[] = {
+ {.core_clk = 100000000, .hldt = 0x2A, .dbcnt = 0x4, .sclfrq = 0xFB, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 62500000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x9D, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 50000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x7E, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 48000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x79, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 40000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x65, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 30000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x4C, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 29000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x49, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 26000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x42, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 25000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x3F, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 24000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x3D, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 20000000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x33, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 16180000, .hldt = 0x2A, .dbcnt = 0x1, .sclfrq = 0x29, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 15000000, .hldt = 0x23, .dbcnt = 0x1, .sclfrq = 0x26, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 13000000, .hldt = 0x1D, .dbcnt = 0x1, .sclfrq = 0x21, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 12000000, .hldt = 0x1B, .dbcnt = 0x1, .sclfrq = 0x1F, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 10000000, .hldt = 0x18, .dbcnt = 0x1, .sclfrq = 0x1A, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 9000000, .hldt = 0x16, .dbcnt = 0x1, .sclfrq = 0x17, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 8090000, .hldt = 0x14, .dbcnt = 0x1, .sclfrq = 0x15, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 7500000, .hldt = 0x7, .dbcnt = 0x1, .sclfrq = 0x13, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 6500000, .hldt = 0xE, .dbcnt = 0x1, .sclfrq = 0x11, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false },
+ {.core_clk = 4000000, .hldt = 0x9, .dbcnt = 0x1, .sclfrq = 0xB, .scllt = 0x0,
+ .sclht = 0x0, .fast_mode = false }
+};
+
+static struct SMB_TIMING_T SMB_TIMING_400KHZ[] = {
+ {.core_clk = 100000000, .hldt = 0x2A, .dbcnt = 0x3, .sclfrq = 0x0, .scllt = 0x47,
+ .sclht = 0x35, .fast_mode = true },
+ {.core_clk = 62500000, .hldt = 0x2A, .dbcnt = 0x2, .sclfrq = 0x0, .scllt = 0x2C,
+ .sclht = 0x22, .fast_mode = true },
+ {.core_clk = 50000000, .hldt = 0x21, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x24,
+ .sclht = 0x1B, .fast_mode = true },
+ {.core_clk = 48000000, .hldt = 0x1E, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x24,
+ .sclht = 0x19, .fast_mode = true },
+ {.core_clk = 40000000, .hldt = 0x1B, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x1E,
+ .sclht = 0x14, .fast_mode = true },
+ {.core_clk = 33000000, .hldt = 0x15, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x19,
+ .sclht = 0x11, .fast_mode = true },
+ {.core_clk = 30000000, .hldt = 0x15, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x19,
+ .sclht = 0xD, .fast_mode = true },
+ {.core_clk = 29000000, .hldt = 0x11, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x15,
+ .sclht = 0x10, .fast_mode = true },
+ {.core_clk = 26000000, .hldt = 0x10, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x13,
+ .sclht = 0xE, .fast_mode = true },
+ {.core_clk = 25000000, .hldt = 0xF, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x13,
+ .sclht = 0xD, .fast_mode = true },
+ {.core_clk = 24000000, .hldt = 0xD, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x12,
+ .sclht = 0xD, .fast_mode = true },
+ {.core_clk = 20000000, .hldt = 0xB, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0xF,
+ .sclht = 0xA, .fast_mode = true },
+ {.core_clk = 16180000, .hldt = 0xA, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0xC,
+ .sclht = 0x9, .fast_mode = true },
+ {.core_clk = 15000000, .hldt = 0x9, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0xB,
+ .sclht = 0x8, .fast_mode = true },
+ {.core_clk = 13000000, .hldt = 0x7, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0xA,
+ .sclht = 0x7, .fast_mode = true },
+ {.core_clk = 12000000, .hldt = 0x7, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0xA,
+ .sclht = 0x6, .fast_mode = true },
+ {.core_clk = 10000000, .hldt = 0x6, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x8,
+ .sclht = 0x5, .fast_mode = true },
+};
+
+static struct SMB_TIMING_T SMB_TIMING_1000KHZ[] = {
+ {.core_clk = 100000000, .hldt = 0x15, .dbcnt = 0x4, .sclfrq = 0x0, .scllt = 0x1C,
+ .sclht = 0x15, .fast_mode = true },
+ {.core_clk = 62500000, .hldt = 0xF, .dbcnt = 0x3, .sclfrq = 0x0, .scllt = 0x11,
+ .sclht = 0xE, .fast_mode = true },
+ {.core_clk = 50000000, .hldt = 0xA, .dbcnt = 0x2, .sclfrq = 0x0, .scllt = 0xE,
+ .sclht = 0xB, .fast_mode = true },
+ {.core_clk = 48000000, .hldt = 0x9, .dbcnt = 0x2, .sclfrq = 0x0, .scllt = 0xD,
+ .sclht = 0xB, .fast_mode = true },
+ {.core_clk = 41000000, .hldt = 0x9, .dbcnt = 0x2, .sclfrq = 0x0, .scllt = 0xC,
+ .sclht = 0x9, .fast_mode = true },
+ {.core_clk = 40000000, .hldt = 0x8, .dbcnt = 0x2, .sclfrq = 0x0, .scllt = 0xB,
+ .sclht = 0x9, .fast_mode = true },
+ {.core_clk = 33000000, .hldt = 0x7, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0xA,
+ .sclht = 0x7, .fast_mode = true },
+ {.core_clk = 25000000, .hldt = 0x4, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x7,
+ .sclht = 0x6, .fast_mode = true },
+ {.core_clk = 24000000, .hldt = 0x7, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x8,
+ .sclht = 0x5, .fast_mode = true },
+ {.core_clk = 20000000, .hldt = 0x4, .dbcnt = 0x1, .sclfrq = 0x0, .scllt = 0x6,
+ .sclht = 0x4, .fast_mode = true },
+};
+
struct npcm_i2c_data {
u8 fifo_size;
u32 segctl_init_val;
@@ -1805,102 +1920,45 @@ static void npcm_i2c_recovery_init(struct i2c_adapter *_adap)
*/
static int npcm_i2c_init_clk(struct npcm_i2c *bus, u32 bus_freq_hz)
{
- u32 k1 = 0;
- u32 k2 = 0;
- u8 dbnct = 0;
- u32 sclfrq = 0;
- u8 hldt = 7;
+ struct SMB_TIMING_T *smb_timing;
+ u8 scl_table_cnt = 0, table_size = 0;
u8 fast_mode = 0;
- u32 src_clk_khz;
- u32 bus_freq_khz;

- src_clk_khz = bus->apb_clk / 1000;
- bus_freq_khz = bus_freq_hz / 1000;
bus->bus_freq = bus_freq_hz;

- /* 100KHz and below: */
- if (bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ) {
- sclfrq = src_clk_khz / (bus_freq_khz * 4);
-
- if (sclfrq < SCLFRQ_MIN || sclfrq > SCLFRQ_MAX)
- return -EDOM;
-
- if (src_clk_khz >= 40000)
- hldt = 17;
- else if (src_clk_khz >= 12500)
- hldt = 15;
- else
- hldt = 7;
- }
-
- /* 400KHz: */
- else if (bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ) {
- sclfrq = 0;
+ switch (bus_freq_hz) {
+ case I2C_MAX_STANDARD_MODE_FREQ:
+ smb_timing = SMB_TIMING_100KHZ;
+ table_size = ARRAY_SIZE(SMB_TIMING_100KHZ);
+ break;
+ case I2C_MAX_FAST_MODE_FREQ:
+ smb_timing = SMB_TIMING_400KHZ;
+ table_size = ARRAY_SIZE(SMB_TIMING_400KHZ);
fast_mode = I2CCTL3_400K_MODE;
-
- if (src_clk_khz < 7500)
- /* 400KHZ cannot be supported for core clock < 7.5MHz */
- return -EDOM;
-
- else if (src_clk_khz >= 50000) {
- k1 = 80;
- k2 = 48;
- hldt = 12;
- dbnct = 7;
- }
-
- /* Master or Slave with frequency > 25MHz */
- else if (src_clk_khz > 25000) {
- hldt = clk_coef(src_clk_khz, 300) + 7;
- k1 = clk_coef(src_clk_khz, 1600);
- k2 = clk_coef(src_clk_khz, 900);
- }
- }
-
- /* 1MHz: */
- else if (bus_freq_hz <= I2C_MAX_FAST_MODE_PLUS_FREQ) {
- sclfrq = 0;
+ break;
+ case I2C_MAX_FAST_MODE_PLUS_FREQ:
+ smb_timing = SMB_TIMING_1000KHZ;
+ table_size = ARRAY_SIZE(SMB_TIMING_1000KHZ);
fast_mode = I2CCTL3_400K_MODE;
-
- /* 1MHZ cannot be supported for core clock < 24 MHz */
- if (src_clk_khz < 24000)
- return -EDOM;
-
- k1 = clk_coef(src_clk_khz, 620);
- k2 = clk_coef(src_clk_khz, 380);
-
- /* Core clk > 40 MHz */
- if (src_clk_khz > 40000) {
- /*
- * Set HLDT:
- * SDA hold time: (HLDT-7) * T(CLK) >= 120
- * HLDT = 120/T(CLK) + 7 = 120 * FREQ(CLK) + 7
- */
- hldt = clk_coef(src_clk_khz, 120) + 7;
- } else {
- hldt = 7;
- dbnct = 2;
- }
+ break;
+ default:
+ return -EINVAL;
}

- /* Frequency larger than 1 MHz is not supported */
- else
- return -EINVAL;
+ for (scl_table_cnt = 0 ; scl_table_cnt < table_size ; scl_table_cnt++)
+ if (bus->apb_clk >= smb_timing[scl_table_cnt].core_clk)
+ break;

- if (bus_freq_hz >= I2C_MAX_FAST_MODE_FREQ) {
- k1 = round_up(k1, 2);
- k2 = round_up(k2 + 1, 2);
- if (k1 < SCLFRQ_MIN || k1 > SCLFRQ_MAX ||
- k2 < SCLFRQ_MIN || k2 > SCLFRQ_MAX)
- return -EDOM;
- }
+ if (scl_table_cnt == table_size)
+ return -EINVAL;

/* write sclfrq value. bits [6:0] are in I2CCTL2 reg */
- iowrite8(FIELD_PREP(I2CCTL2_SCLFRQ6_0, sclfrq & 0x7F),
+ iowrite8(FIELD_PREP(I2CCTL2_SCLFRQ6_0, smb_timing[scl_table_cnt].sclfrq & 0x7F),
bus->reg + NPCM_I2CCTL2);

/* bits [8:7] are in I2CCTL3 reg */
- iowrite8(fast_mode | FIELD_PREP(I2CCTL3_SCLFRQ8_7, (sclfrq >> 7) & 0x3),
+ iowrite8(fast_mode | FIELD_PREP(I2CCTL3_SCLFRQ8_7, (smb_timing[scl_table_cnt].sclfrq >> 7)
+ & 0x3),
bus->reg + NPCM_I2CCTL3);

/* Select Bank 0 to access NPCM_I2CCTL4/NPCM_I2CCTL5 */
@@ -1912,13 +1970,13 @@ static int npcm_i2c_init_clk(struct npcm_i2c *bus, u32 bus_freq_hz)
* k1 = 2 * SCLLT7-0 -> Low Time = k1 / 2
* k2 = 2 * SCLLT7-0 -> High Time = k2 / 2
*/
- iowrite8(k1 / 2, bus->reg + NPCM_I2CSCLLT);
- iowrite8(k2 / 2, bus->reg + NPCM_I2CSCLHT);
+ iowrite8(smb_timing[scl_table_cnt].scllt, bus->reg + NPCM_I2CSCLLT);
+ iowrite8(smb_timing[scl_table_cnt].sclht, bus->reg + NPCM_I2CSCLHT);

- iowrite8(dbnct, bus->reg + NPCM_I2CCTL5);
+ iowrite8(smb_timing[scl_table_cnt].dbcnt, bus->reg + NPCM_I2CCTL5);
}

- iowrite8(hldt, bus->reg + NPCM_I2CCTL4);
+ iowrite8(smb_timing[scl_table_cnt].hldt, bus->reg + NPCM_I2CCTL4);

/* Return to Bank 1, and stay there by default: */
npcm_i2c_select_bank(bus, I2C_BANK_1);
--
2.34.1