| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Wolfram Sang | 1688 | 76.59% | 4 | 23.53% |
| Chris Brandt | 332 | 15.06% | 4 | 23.53% |
| Geert Uytterhoeven | 93 | 4.22% | 1 | 5.88% |
| Lad Prabhakar | 52 | 2.36% | 3 | 17.65% |
| Biju Das | 26 | 1.18% | 1 | 5.88% |
| Peter Rosin | 6 | 0.27% | 1 | 5.88% |
| Andy Shevchenko | 4 | 0.18% | 1 | 5.88% |
| Uwe Kleine-König | 2 | 0.09% | 1 | 5.88% |
| Jingoo Han | 1 | 0.05% | 1 | 5.88% |
| Total | 2204 | 17 |
// SPDX-License-Identifier: GPL-2.0 /* * Renesas RIIC driver * * Copyright (C) 2013 Wolfram Sang <wsa@sang-engineering.com> * Copyright (C) 2013 Renesas Solutions Corp. */ /* * This i2c core has a lot of interrupts, namely 8. We use their chaining as * some kind of state machine. * * 1) The main xfer routine kicks off a transmission by putting the start bit * (or repeated start) on the bus and enabling the transmit interrupt (TIE) * since we need to send the slave address + RW bit in every case. * * 2) TIE sends slave address + RW bit and selects how to continue. * * 3a) Write case: We keep utilizing TIE as long as we have data to send. If we * are done, we switch over to the transmission done interrupt (TEIE) and mark * the message as completed (includes sending STOP) there. * * 3b) Read case: We switch over to receive interrupt (RIE). One dummy read is * needed to start clocking, then we keep receiving until we are done. Note * that we use the RDRFS mode all the time, i.e. we ACK/NACK every byte by * writing to the ACKBT bit. I tried using the RDRFS mode only at the end of a * message to create the final NACK as sketched in the datasheet. This caused * some subtle races (when byte n was processed and byte n+1 was already * waiting), though, and I started with the safe approach. * * 4) If we got a NACK somewhere, we flag the error and stop the transmission * via NAKIE. * * Also check the comments in the interrupt routines for some gory details. */ #include <linux/clk.h> #include <linux/completion.h> #include <linux/err.h> #include <linux/i2c.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/reset.h> #define RIIC_ICCR1 0x00 #define RIIC_ICCR2 0x04 #define RIIC_ICMR1 0x08 #define RIIC_ICMR3 0x10 #define RIIC_ICSER 0x18 #define RIIC_ICIER 0x1c #define RIIC_ICSR2 0x24 #define RIIC_ICBRL 0x34 #define RIIC_ICBRH 0x38 #define RIIC_ICDRT 0x3c #define RIIC_ICDRR 0x40 #define ICCR1_ICE 0x80 #define ICCR1_IICRST 0x40 #define ICCR1_SOWP 0x10 #define ICCR2_BBSY 0x80 #define ICCR2_SP 0x08 #define ICCR2_RS 0x04 #define ICCR2_ST 0x02 #define ICMR1_CKS_MASK 0x70 #define ICMR1_BCWP 0x08 #define ICMR1_CKS(_x) ((((_x) << 4) & ICMR1_CKS_MASK) | ICMR1_BCWP) #define ICMR3_RDRFS 0x20 #define ICMR3_ACKWP 0x10 #define ICMR3_ACKBT 0x08 #define ICIER_TIE 0x80 #define ICIER_TEIE 0x40 #define ICIER_RIE 0x20 #define ICIER_NAKIE 0x10 #define ICIER_SPIE 0x08 #define ICSR2_NACKF 0x10 #define ICBR_RESERVED 0xe0 /* Should be 1 on writes */ #define RIIC_INIT_MSG -1 struct riic_dev { void __iomem *base; u8 *buf; struct i2c_msg *msg; int bytes_left; int err; int is_last; struct completion msg_done; struct i2c_adapter adapter; struct clk *clk; }; struct riic_irq_desc { int res_num; irq_handler_t isr; char *name; }; static inline void riic_clear_set_bit(struct riic_dev *riic, u8 clear, u8 set, u8 reg) { writeb((readb(riic->base + reg) & ~clear) | set, riic->base + reg); } static int riic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) { struct riic_dev *riic = i2c_get_adapdata(adap); unsigned long time_left; int i; u8 start_bit; pm_runtime_get_sync(adap->dev.parent); if (readb(riic->base + RIIC_ICCR2) & ICCR2_BBSY) { riic->err = -EBUSY; goto out; } reinit_completion(&riic->msg_done); riic->err = 0; writeb(0, riic->base + RIIC_ICSR2); for (i = 0, start_bit = ICCR2_ST; i < num; i++) { riic->bytes_left = RIIC_INIT_MSG; riic->buf = msgs[i].buf; riic->msg = &msgs[i]; riic->is_last = (i == num - 1); writeb(ICIER_NAKIE | ICIER_TIE, riic->base + RIIC_ICIER); writeb(start_bit, riic->base + RIIC_ICCR2); time_left = wait_for_completion_timeout(&riic->msg_done, riic->adapter.timeout); if (time_left == 0) riic->err = -ETIMEDOUT; if (riic->err) break; start_bit = ICCR2_RS; } out: pm_runtime_put(adap->dev.parent); return riic->err ?: num; } static irqreturn_t riic_tdre_isr(int irq, void *data) { struct riic_dev *riic = data; u8 val; if (!riic->bytes_left) return IRQ_NONE; if (riic->bytes_left == RIIC_INIT_MSG) { if (riic->msg->flags & I2C_M_RD) /* On read, switch over to receive interrupt */ riic_clear_set_bit(riic, ICIER_TIE, ICIER_RIE, RIIC_ICIER); else /* On write, initialize length */ riic->bytes_left = riic->msg->len; val = i2c_8bit_addr_from_msg(riic->msg); } else { val = *riic->buf; riic->buf++; riic->bytes_left--; } /* * Switch to transmission ended interrupt when done. Do check here * after bytes_left was initialized to support SMBUS_QUICK (new msg has * 0 length then) */ if (riic->bytes_left == 0) riic_clear_set_bit(riic, ICIER_TIE, ICIER_TEIE, RIIC_ICIER); /* * This acks the TIE interrupt. We get another TIE immediately if our * value could be moved to the shadow shift register right away. So * this must be after updates to ICIER (where we want to disable TIE)! */ writeb(val, riic->base + RIIC_ICDRT); return IRQ_HANDLED; } static irqreturn_t riic_tend_isr(int irq, void *data) { struct riic_dev *riic = data; if (readb(riic->base + RIIC_ICSR2) & ICSR2_NACKF) { /* We got a NACKIE */ readb(riic->base + RIIC_ICDRR); /* dummy read */ riic_clear_set_bit(riic, ICSR2_NACKF, 0, RIIC_ICSR2); riic->err = -ENXIO; } else if (riic->bytes_left) { return IRQ_NONE; } if (riic->is_last || riic->err) { riic_clear_set_bit(riic, ICIER_TEIE, ICIER_SPIE, RIIC_ICIER); writeb(ICCR2_SP, riic->base + RIIC_ICCR2); } else { /* Transfer is complete, but do not send STOP */ riic_clear_set_bit(riic, ICIER_TEIE, 0, RIIC_ICIER); complete(&riic->msg_done); } return IRQ_HANDLED; } static irqreturn_t riic_rdrf_isr(int irq, void *data) { struct riic_dev *riic = data; if (!riic->bytes_left) return IRQ_NONE; if (riic->bytes_left == RIIC_INIT_MSG) { riic->bytes_left = riic->msg->len; readb(riic->base + RIIC_ICDRR); /* dummy read */ return IRQ_HANDLED; } if (riic->bytes_left == 1) { /* STOP must come before we set ACKBT! */ if (riic->is_last) { riic_clear_set_bit(riic, 0, ICIER_SPIE, RIIC_ICIER); writeb(ICCR2_SP, riic->base + RIIC_ICCR2); } riic_clear_set_bit(riic, 0, ICMR3_ACKBT, RIIC_ICMR3); } else { riic_clear_set_bit(riic, ICMR3_ACKBT, 0, RIIC_ICMR3); } /* Reading acks the RIE interrupt */ *riic->buf = readb(riic->base + RIIC_ICDRR); riic->buf++; riic->bytes_left--; return IRQ_HANDLED; } static irqreturn_t riic_stop_isr(int irq, void *data) { struct riic_dev *riic = data; /* read back registers to confirm writes have fully propagated */ writeb(0, riic->base + RIIC_ICSR2); readb(riic->base + RIIC_ICSR2); writeb(0, riic->base + RIIC_ICIER); readb(riic->base + RIIC_ICIER); complete(&riic->msg_done); return IRQ_HANDLED; } static u32 riic_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm riic_algo = { .master_xfer = riic_xfer, .functionality = riic_func, }; static int riic_init_hw(struct riic_dev *riic, struct i2c_timings *t) { int ret = 0; unsigned long rate; int total_ticks, cks, brl, brh; pm_runtime_get_sync(riic->adapter.dev.parent); if (t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ) { dev_err(&riic->adapter.dev, "unsupported bus speed (%dHz). %d max\n", t->bus_freq_hz, I2C_MAX_FAST_MODE_FREQ); ret = -EINVAL; goto out; } rate = clk_get_rate(riic->clk); /* * Assume the default register settings: * FER.SCLE = 1 (SCL sync circuit enabled, adds 2 or 3 cycles) * FER.NFE = 1 (noise circuit enabled) * MR3.NF = 0 (1 cycle of noise filtered out) * * Freq (CKS=000) = (I2CCLK + tr + tf)/ (BRH + 3 + 1) + (BRL + 3 + 1) * Freq (CKS!=000) = (I2CCLK + tr + tf)/ (BRH + 2 + 1) + (BRL + 2 + 1) */ /* * Determine reference clock rate. We must be able to get the desired * frequency with only 62 clock ticks max (31 high, 31 low). * Aim for a duty of 60% LOW, 40% HIGH. */ total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz ?: 1); for (cks = 0; cks < 7; cks++) { /* * 60% low time must be less than BRL + 2 + 1 * BRL max register value is 0x1F. */ brl = ((total_ticks * 6) / 10); if (brl <= (0x1F + 3)) break; total_ticks /= 2; rate /= 2; } if (brl > (0x1F + 3)) { dev_err(&riic->adapter.dev, "invalid speed (%lu). Too slow.\n", (unsigned long)t->bus_freq_hz); ret = -EINVAL; goto out; } brh = total_ticks - brl; /* Remove automatic clock ticks for sync circuit and NF */ if (cks == 0) { brl -= 4; brh -= 4; } else { brl -= 3; brh -= 3; } /* * Remove clock ticks for rise and fall times. Convert ns to clock * ticks. */ brl -= t->scl_fall_ns / (1000000000 / rate); brh -= t->scl_rise_ns / (1000000000 / rate); /* Adjust for min register values for when SCLE=1 and NFE=1 */ if (brl < 1) brl = 1; if (brh < 1) brh = 1; pr_debug("i2c-riic: freq=%lu, duty=%d, fall=%lu, rise=%lu, cks=%d, brl=%d, brh=%d\n", rate / total_ticks, ((brl + 3) * 100) / (brl + brh + 6), t->scl_fall_ns / (1000000000 / rate), t->scl_rise_ns / (1000000000 / rate), cks, brl, brh); /* Changing the order of accessing IICRST and ICE may break things! */ writeb(ICCR1_IICRST | ICCR1_SOWP, riic->base + RIIC_ICCR1); riic_clear_set_bit(riic, 0, ICCR1_ICE, RIIC_ICCR1); writeb(ICMR1_CKS(cks), riic->base + RIIC_ICMR1); writeb(brh | ICBR_RESERVED, riic->base + RIIC_ICBRH); writeb(brl | ICBR_RESERVED, riic->base + RIIC_ICBRL); writeb(0, riic->base + RIIC_ICSER); writeb(ICMR3_ACKWP | ICMR3_RDRFS, riic->base + RIIC_ICMR3); riic_clear_set_bit(riic, ICCR1_IICRST, 0, RIIC_ICCR1); out: pm_runtime_put(riic->adapter.dev.parent); return ret; } static struct riic_irq_desc riic_irqs[] = { { .res_num = 0, .isr = riic_tend_isr, .name = "riic-tend" }, { .res_num = 1, .isr = riic_rdrf_isr, .name = "riic-rdrf" }, { .res_num = 2, .isr = riic_tdre_isr, .name = "riic-tdre" }, { .res_num = 3, .isr = riic_stop_isr, .name = "riic-stop" }, { .res_num = 5, .isr = riic_tend_isr, .name = "riic-nack" }, }; static void riic_reset_control_assert(void *data) { reset_control_assert(data); } static int riic_i2c_probe(struct platform_device *pdev) { struct riic_dev *riic; struct i2c_adapter *adap; struct i2c_timings i2c_t; struct reset_control *rstc; int i, ret; riic = devm_kzalloc(&pdev->dev, sizeof(*riic), GFP_KERNEL); if (!riic) return -ENOMEM; riic->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(riic->base)) return PTR_ERR(riic->base); riic->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(riic->clk)) { dev_err(&pdev->dev, "missing controller clock"); return PTR_ERR(riic->clk); } rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL); if (IS_ERR(rstc)) return dev_err_probe(&pdev->dev, PTR_ERR(rstc), "Error: missing reset ctrl\n"); ret = reset_control_deassert(rstc); if (ret) return ret; ret = devm_add_action_or_reset(&pdev->dev, riic_reset_control_assert, rstc); if (ret) return ret; for (i = 0; i < ARRAY_SIZE(riic_irqs); i++) { ret = platform_get_irq(pdev, riic_irqs[i].res_num); if (ret < 0) return ret; ret = devm_request_irq(&pdev->dev, ret, riic_irqs[i].isr, 0, riic_irqs[i].name, riic); if (ret) { dev_err(&pdev->dev, "failed to request irq %s\n", riic_irqs[i].name); return ret; } } adap = &riic->adapter; i2c_set_adapdata(adap, riic); strscpy(adap->name, "Renesas RIIC adapter", sizeof(adap->name)); adap->owner = THIS_MODULE; adap->algo = &riic_algo; adap->dev.parent = &pdev->dev; adap->dev.of_node = pdev->dev.of_node; init_completion(&riic->msg_done); i2c_parse_fw_timings(&pdev->dev, &i2c_t, true); pm_runtime_enable(&pdev->dev); ret = riic_init_hw(riic, &i2c_t); if (ret) goto out; ret = i2c_add_adapter(adap); if (ret) goto out; platform_set_drvdata(pdev, riic); dev_info(&pdev->dev, "registered with %dHz bus speed\n", i2c_t.bus_freq_hz); return 0; out: pm_runtime_disable(&pdev->dev); return ret; } static void riic_i2c_remove(struct platform_device *pdev) { struct riic_dev *riic = platform_get_drvdata(pdev); pm_runtime_get_sync(&pdev->dev); writeb(0, riic->base + RIIC_ICIER); pm_runtime_put(&pdev->dev); i2c_del_adapter(&riic->adapter); pm_runtime_disable(&pdev->dev); } static const struct of_device_id riic_i2c_dt_ids[] = { { .compatible = "renesas,riic-rz", }, { /* Sentinel */ }, }; static struct platform_driver riic_i2c_driver = { .probe = riic_i2c_probe, .remove_new = riic_i2c_remove, .driver = { .name = "i2c-riic", .of_match_table = riic_i2c_dt_ids, }, }; module_platform_driver(riic_i2c_driver); MODULE_DESCRIPTION("Renesas RIIC adapter"); MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>"); MODULE_LICENSE("GPL v2"); MODULE_DEVICE_TABLE(of, riic_i2c_dt_ids);
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